Research ArticleA New Generation of Glycoconjugated Azo DyesBased on Aminosugars

Lorenzo Guazzelli12 Giorgio Catelani1 and Felicia DrsquoAndrea1

1Department of Pharmacy University of Pisa Via Bonanno 33 56126 Pisa Italy2School of Chemistry and Chemical Biology University College Dublin Belfield Dublin 4 Ireland

Correspondence should be addressed to Lorenzo Guazzelli lorenzoguazzelliucdieand Giorgio Catelani giorgiocatelanifarmunipiit

Received 7 May 2015 Revised 13 July 2015 Accepted 14 July 2015

Academic Editor Vladimir Kren

Copyright copy 2015 Lorenzo Guazzelli et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

The third generation of glycoconjugated azo dyes (GADs) was prepared linking monoazo dyes to 6-amino-6-deoxy-d-galactose or61015840amino-61015840-deoxylactose through mixed amido-ester connections The complementary conjugation reactions were studied usingthe succinyl derivative of either the acetal protected aminosugar or the azo dye Target ldquonaturalizedrdquo GADs were obtained after acidhydrolysis of the acetal protecting groups present on the sugar moiety

1 Introduction

Themost commonly employed class of industrial textile dyesare the so-called ldquodisperse dyesrdquo family characterised bytheir extremely low solubility in water These in a finelydispersed state are used in dyeing processes of syntheticfibres such as polyester polyacetate and polyamide Owingto the absence of ionic groups in these synthetic fibresonly apolar dyes can be utilized [1ndash3] Among the varioustroublesome aspects related to the use of disperse dyes andtheir dyeing processes the highest concerns are raised by (a)the use of substantial amounts of dispersing agents whichare needed to bring the insoluble dyes in a stable colloidaldispersion throughout the application process and (b) theuse of high temperatures typically around 130∘C whichdemand large amounts of energy and require appropriatedyeing machines able to operate under pressure [1ndash3] Azoand anthraquinone dyes represent the two most relevanttypes of disperse dyes Although disperse dyes can differconsiderably in molecular weight only those with a lowmass(typically between 200 and 500Da) [1] are effectively used inthe dyeing of textile apolar synthetic fibres

Recently an innovative class of azo dyes [4ndash6] has beenproposed These have been obtained through the glycocon-jugation of common mono- and disaccharides such as d-

glucose d-galactose and lactose with some model syntheticmonoazo dyes Glycoconjugated azo dyes (GADs) have beenprepared by the so-called ldquonaturalisationrdquo procedure whichis to link the azo dye component and the sugar componentthrough difunctional spacers by means of either two con-secutive esterification reactions or two consecutive alkylationreactions Glycoconjugated azo dyes (GADs Figure 1) type1 [4 5] and type 2 [6] characterised respectively by diesterand diether bonds have been evaluated for their tinctorialproperties giving unexpected results In fact GADs dyesynthetic fibres quickly in boiling water at ambient pressureand without the need of dispersant thanks to the increasedhydrophilic characteristics Uniquely GADs can also be usedeffectively to dye natural fibres such as wool and silkallowing the study of solutions to novel dyeing technologiesMoreover biodegradation and detoxification of a selected di-estereal GAD by Fusarium oxysporum gave promising results[7] for the treatment of the aqueous waste representinga step further towards environmentally friendly tinctorialprocesses

In a more recent investigation [8] high molecular weightanthraquinone or bis-azo disperse dyes only become water-soluble after conjugation with two lactose units The double-conjugation procedure required a preliminary insertion ofa malonate spacer followed by condensation with two 61015840-

Hindawi Publishing CorporationInternational Journal of Carbohydrate ChemistryVolume 2015 Article ID 235763 7 pageshttpdxdoiorg1011552015235763

2 International Journal of Carbohydrate Chemistry

Sugar DyeX YSpacer

(1) X = Y = OCO(2) X = Y = O(3) X = NHCOY = OCO

Figure 1 General structure of glycoconjugated azo dyes (GADs)

amino-61015840-deoxylactose units [8] Also glutamic acid wasused as the additional spacer in order to allow the double-conjugation [9] Presented here is an extension of our previ-ous results namely the synthesis of the third generation ofnaturalized GADs by conjugation of low molecular weightmonoazo dyes with either 6-amino-6-deoxy-d-galactose or61015840-amino-61015840-deoxylactose through mixed amido-ester con-nections (3)

2 Experimental

Optical rotations were measured with a Perkin-Elmer 241polarimeter at the sodiumD-line (589 nm) at 20plusmn2∘C using a1 dm cell 1HNMR and 13CNMR spectra were recorded witha Bruker AC 200 operating at 20013 (1H) and 503MHz (13C)or with a Bruker Avance II 250 spectrometer operating at25012 (1H) and 629MHz (13C) Spin resonances werereported as chemical shifts (120575) in part per million (ppm) andthe references to the residual peak of the solvent employed asfollows CDCl

3727 ppm (1HNMR) and 770 ppm (13CNMR

central band) CD3CN 194 ppm (1HNMR central band) and

128 ppm (13C NMR central band) and CD3OD 331 ppm

(1H NMR central band) and 490 ppm (13C NMR centralband) Coupling constants 119869 were reported in Hertz (Hz)The assignments were made when possible with the aidof DEPT HETCOR COSY and HSQC experiments and inthe case of anomeric mixtures referring to the differences inthe peak intensities and comparison with values for knownanalogous compounds UV-Vis spectra were recorded ona Cary-300 Agilent Technologies Cary Series UV-VisSpectrophotometer Elemental analyses were performed byCarlo Erba elemental analyzer MOD 1106 instrumentAll reactions were followed by TLC on Kieselgel 60 F

254

with detection by UV light andor with ethanolic 10phosphomolybdic or sulfuric acid and heating Kieselgel 60(E Merck 70ndash230 and 230ndash400 mesh resp) was used forcolumn and flash chromatography Solvents were dried andpurified by distillation according to standard procedure[10] and stored over 4 A molecular sieves activated for atleast 24 h at 200∘C Na

2SO4or MgSO

4was used as the

drying agent for solutions 6-Amino-6-deoxy-1234-di-O-isopropylidene-120572-d-galactopyranose (4) [11] 6-amino-6-deoxy-34-O-isopropylidene-120573-d-galactopyranosyl-(1rarr 4)-2356-di-O-isopropylidene-aldehydo-d-glucose dimethylacetal (5) [8] 2-[ethyl-(4-phenyldiazenyl)-phenyl-amino]-ethanol (8) [12] and 4-[2-ethyl-(4-[(4-nitrophenyl)dia-

zenyl]phenylamino)ethoxy]-4-oxobutanoic acid (10) [4]were prepared through literature methods

21 6-N-(3-Carboxy-propanoyl)-6-deoxy-1234-di-O-isopro-pylidene-120572-d-galactopyranose (6) A solution of 4 [11](260 g 100mmol) in MeOH (70mL) was treated withsuccinic anhydride (120 g 120mmol 12 eq) and stirred atroom temperature until the starting material was completelydisappeared (TLC 91 EtOAc-iPrOH) After 2 h Et

3N (3mL)

was added to the reaction mixture which was stirred for10min at room temperature and then was repeatedlycoevaporated with toluene (5 times 20mL) at diminishedpressure The resulting residue was dissolved into CH

2Cl2

(50mL) neutralized with AcOH (6mL) and washed withwater (25mL) and the aqueous phase was extracted withCH2Cl2(4 times 30mL) The combined organic layers were

dried (MgSO4) filtered and concentrated under diminished

pressure The crude residue (342 g) was subjected to flashchromatographic purification on silica gel (EtOAc) to givepure 6 as white foam (275 g 76 yield) [120572]D minus98 (119888 11CHCl

3) 119877119891050 (91 EtOAc-iPrOH) 1H NMR (20013MHz

CDCl3) 120575 129 131 138 143 [4s each 3H 2 times C(CH

3)3]

241ndash255 [m 4H (CH2)2] 316 (ddd 1H 1198696a6b 137Hz 1198696aNH

53Hz 11986956a 80Hz H-6a) 342 (ddd 1H 1198696bNH 64Hz

11986956b 47Hz H-6b) 386 (ddd 1H H-5) 419 (dd 1H 119869

3479Hz 119869

45 18Hz H-4) 431 (dd 1H 11986912 50Hz 119869

23 24HzH-2) 459 (dd 1H H-3) 543 (d 1H H-1) 680 (bt 1HNH) 13C NMR (503MHz CDCl

3) 120575 246 252 262 263

[2 times C(CH3)3] 302 310 [(CH

2)2] 408 (C-6) 669 (C-5)

714 716 722 (C-2 C-3 C-4) 971 (C-1) 1094 1098 [2 timesC(CH

3)3] 1738 1746 (2timesC=O) Anal Calcd for C

16H25NO8

(35937) C 5347 H 701 N 390 Found C 5344 H 699N 388

22 6-N-(3-Carboxy-propanoyl)-6-deoxy-34-O-isopropylid-ene-120573-d-galactopyranosyl-(1rarr 4)-2356-di-O-isopropylide-ne-aldehydo-d-glucose Dimethyl Acetal (7) A solution ofamine 5 [8] (100 g 197mmol) and succinic anhydride(216mg 216mmol 12 eq) in MeOH (40mL) was allowed toreact in the reaction conditions described for the preparationof 6 leading to the residue (117 g) constituted exclusively(13C NMR) by 7 (98 yield) An analytical sample of 7was obtained through flash chromatography over silica geleluting with 91 EtOAc-iPrOH Compound 7 was a whitefoam [120572]D +532 (119888 11 CHCl

3) 119877119891051 (91 EtOAc-iPrOH)

1H NMR (25012MHz CD3CN) 120575 129 134 [2s each 6H

2 times C(CH3)3] 139 143 [2s each 3H C(CH

3)3] 251 [m

4H (CH2)2] 344 349 (2s each 3H 2 times OCH

3) 313 (ddd

1H 11986951015840 61015840a 68Hz 11986961015840aNH 49Hz 11986961015840a61015840b 138Hz H-61015840a) 333(dd 1H 119869

1101584021015840 81 Hz 119869

2101584031015840 73Hz H-21015840) 367ndash380 (m 2H

H-51015840 H-61015840b) 384 (dd 1H 11986934 13Hz 119869

45 54Hz H-4)399 (dd 1H 119869

3101584041015840 32Hz H-31015840) 406 (m 3H H-3 H-6a

OH-21015840) 409 (dd 1H 1198694101584051015840 51 Hz H-41015840) 422 (m 2H H-5

H-6b) 433 (d 1H H-11015840) 436 (d 1H 11986912 64Hz H-1)

441 (dd 1H 11986923 71 Hz H-2) 685 (bt 1H NH) 13C NMR

(629MHz CD3CN) 120575 252 265 266 269 274 284 [3 times

C(CH3)3] 301 310 [(CH

2)2] 581 560 (2 times OCH

3) 411

International Journal of Carbohydrate Chemistry 3

(C-61015840) 661 (C-6) 746 (C-21015840) 725 (C-51015840) 750 (C-41015840) 774(C-2) 776 (C-5) 777 (C-4) 784 (C-3) 800 (C-31015840) 1040(C-11015840) 1082 (C-1) 1093 1104 1107 [3 times C(CH

3)3] 1736

1747 (2 times C=O) Anal Calcd for C27H45NO14

(60728) C5337 H 746 N 231 Found C 5335 H 743 N 229

23 Preparation of Protected GAD 11 A solution of 6(150 g 417mmol) and azo dye 9 (181 g 517mmol124 eq) in dry THF (50mL) was treated with NN1015840-dicyclohexylcarbodiimide (DDC) (103 g 50mmol 12 eq)and 4-dimethylaminopyridine (DMAP) (145mg 119mmol)and the solution was stirred at room temperature until thestarting material was completely disappeared (4 h TLCEtOAc) The reaction mixture was concentrated underdiminished pressure and the crude residue was dissolvedinto CH

2Cl2(70mL) and washed in the order with saturated

aqueous NaHCO3(3 times 30mL) and brine (30mL) The

organic phase was dried (Na2SO4) filtered and concentrated

under diminished pressure Purification of the crude residue(310 g) by flash chromatography over silica gel (23 hexane-EtOAc) gave pure 11 as a red foam (214 g 74 yield) 119877

119891

022 (23 hexane-EtOAc) 1H NMR (20013MHz CDCl3) 120575

127 (t 3H J 72Hz CH3) 132 133 145 148 [4s each 3H

2 times C(CH3)3] 265 248 [2m each 2H (CH

2)2] 320 (ddd

1H 1198696a6b 139Hz 11986956a 89Hz 1198696aNH 37Hz H-6a) 355 (q

2H J 72Hz CH3CH2N) 370 (t 2H J 62Hz OCH

2CH2N)

372 (ddd 1H 11986956b 35Hz 1198696bNH 72Hz H-6b) 387 (ddd

1H H-5) 419 (dd 1H 11986945 17Hz 119869

34 79Hz H-4) 431(dd 1H 119869

12 50Hz 11986923 25Hz H-2) 432 (t 2H J 62Hz

CH2OCO) 459 (dd 1H H-3) 551 (d 1H H-1) 598 (dd

1H NH) 779 (d 1H Ar-H-6) 687 796 (AA1015840XX1015840 system4H Ar-H-8 Ar-H-9 Ar-H-11 Ar-H-12) 816 (dd 1H 119869

5690Hz Ar-H-5) 840 (d 1H 119869

35 24Hz Ar-H-3) 13C NMR(503MHz CDCl

3) 120575 122 (CH

3) 243 249 259 260 [2 times

C(CH3)3] 293 306 [(CH

2)2] 400 (C-6) 458 (CH

3CH2N)

488 (OCH2CH2N) 613 (CH

2OCO) 663 (C-5) 705 (C-2)

706 (C-3) 716 (C-4) 961 (C-1) 1087 1094 [2 times C(CH3)3]

1115 1116 1179 1225 1259 1269 1269 (7 times Ar-CH)1339 (Ar-C-2) 1444 (Ar-C-7) 1471 (Ar-C-4) 1516 1530(Ar-C-1 Ar-C-10) 1713 1727 (2 times C=O) Anal Calcd forC32H40ClN5O10

(69014) C 5569 H 584 N 1015 FoundC 5566 H 583 N 1012

24 Preparation of Protected GAD 12 The condensationof 7 (150 g 247mmol) and azo dye 9 (106 g 305mmol124 eq) with NN1015840-dicyclohexylcarbodiimide (DDC)(630mg 305mmol) and 4-dimethylaminopyridine (DMAP)(90mg 073mmol) in dry THF (30mL) was performedaccording to the procedure described above for 11 The flashchromatography over silica gel of the crude product (14hexane-EtOAc) led to pure 12 (190 g 82 yield) as a redfoam 119877

119891027 (14 hexane-EtOAc) 120582max 49300 nm (MeOH)

1H NMR (25012MHz CD3CN) 120575 120 (t 3H J 71 Hz

CH3) 128 133 [2s each 6H 2 times C(CH

3)3] 137 142 [2s

each 3H C(CH3)3] 244 255 [2m each 2H (CH

2)2] 343

347 (2s each 3H 2 times OCH3) 309 (ddd 1H 11986951015840 61015840a 81 Hz

11986961015840aNH 55Hz 11986961015840a61015840b 138Hz H-61015840a) 330ndash341 (m 2H H-21015840

OH-21015840) 352 (q 2H J 71 Hz CH3CH2N) 360ndash378 (m

4H OCH2CH2N H-51015840 H-61015840b) 382 (dd 1H 119869

34 12Hz11986945 48Hz H-4) 390ndash412 (m 5H H-31015840 H-41015840 H-3 H-6aH-6b) 418 (m 1H H-5) 425 (t 2H J 61Hz CH

2OCO)

430 (d 1H 1198691101584021015840 82Hz H-11015840) 434 (d 1H 119869

12 65Hz H-1)440 (dd 1H 119869

23 71Hz H-2) 667 (bt 1H NH) 773 (d 1HAr-H-6) 686 785 (AA1015840XX1015840 system 4H Ar-H-8 Ar-H-9Ar-H-11 Ar-H-12) 815 (dd 1H 119869

56 90Hz Ar-H-5) 837 (d1H 11986935 24Hz Ar-H-3) 13C NMR (629MHz CD

3CN) 120575

124 (CH3) 251 265 266 269 274 284 [3 times C(CH

3)3]

291 309 [(CH2)2] 409 (C-61015840) 464 (CH

3CH2N) 495

(OCH2CH2N) 560 580 (2 times OCH

3) 661 (C-6) 623

(CH2OCO) 746 (C-21015840) 727 (C-51015840) 750 (C-41015840) 774 (C-2)

776 (C-5) 778 (C-4) 784 (C-3) 801 (C-31015840) 1040 (C-11015840)1082 (C-1) 1094 1106 1107 [3 times C(CH

3)3] 1127 1127 1188

1239 1268 1276 1277 (7 times Ar-CH) 1341 (Ar-C-2) 1448(Ar-C-7) 1482 (Ar-C-4) 1533 1538 (Ar-C-1 Ar-C-10)1723 1737 (2 times C=O) Anal Calcd for C

43H60ClN5O16

(93841) C 5504 H 644 N 746 Found C 5502 H 642N 743

25 Preparation of Protected GAD 13 A solution of 6 (10 g278mmol) azo dye 8 (950mg 352mmol 125 eq) NN1015840-dicyclohexylcarbodiimide (DDC) (688mg 334mmol) and4-dimethylaminopyridine (DMAP) (102mg 083mmol) indry THF (30mL) was allowed to react in the reactionconditions described for the preparation of 11The flash chro-matography over silica gel (11 hexane-EtOAc) afforded pure13 (147 g 86 yield) as a yellow foam 119877

119891031 (46 hexane-

EtOAc) 120582max 40700 nm (MeOH) 1H NMR (20013MHzCDCl

3) 120575 122 (t 3H J 70Hz CH

3) 130 133 144 148 [4s

each 3H 2 times C(CH3)3] 247 266 [2m each 2H (CH

2)2]

320 (ddd 1H 1198696a6b 140Hz 11986956a 90Hz 1198696aNH 38Hz H-

6a) 349 (q 2H J 70Hz CH3CH2N) 364 (t 2H J 62Hz

OCH2CH2N) 371 (ddd 1H 119869

56b 35Hz 1198696bNH 77Hz H-6b)387 (ddd 1H H-5) 418 (dd 1H 119869

34 79Hz 11986945 18Hz H-4)

430 (dd 1H 11986912 50Hz 119869

23 24Hz H-2) 428 (t 2H J 62HzCH2OCO) 457 (dd 1H H-3) 550 (d 1H H-1) 600 (dd 1H

NH) 678 (m 2H Ar-H-9 Ar-H-11) 737ndash751 (m 3H Ar-H-3 Ar-H-4 Ar-H-5) 781ndash790 (m 4H Ar-H-2 Ar-H-6 Ar-H-8 Ar-H-12) 13CNMR (503MHz CDCl

3) 120575 122 (CH

3) 243

249 258 259 [2 times C(CH3)3] 293 307 [(CH

2)2] 400 (C-

6) 455 (CH3CH2N) 487 (OCH

2CH2N) 615 (CH

2OCO)

663 (C-5) 705 (C-2) 707 (C-3) 716 (C-4) 962 (C-1) 10871094 [2 times C(CH

3)3] 1113 1221 1252 1264 1289 (Ar-CH)

1436 (Ar-C-7) 1499 1530 (Ar-C-1 Ar-C-10) 1714 1727 (2timesC=O) Anal Calcd for C

32H42N4O8(61070) C 6294 H

693 N 917 Found C 6291 H 690 N 915

26 Preparation of Protected GAD 14 A solution of azo dye10 (152mg 0367mmol) and amine 4 (114mg 0441mmol12 eq) in dry THF (4mL) was stirred at room tem-perature (10min) 4-(46-Dimethoxy-135-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM) [13] (122mg0441mmol 12 eq) was added and the mixture was stirredat room temperature until azo dye 10 was completely disap-peared (20 h TLC EtOAc) The reaction mixture was con-centrated under diminished pressure and the crude residue

4 International Journal of Carbohydrate Chemistry

was partitioned between water (10mL) and Et2O (10mL)

and the aqueous phase extracted with Et2O (3 times 10mL) The

collected organic phases were dried (Na2SO4) filtered and

concentrated under diminished pressure Purification of thecrude residue (310 g) by flash chromatography over silica gel(14 hexane-EtOAc) gave pure 14 as a red foam solid (230mg95 yield calculated from 10) 119877

119891045 (EtOAc) 1H NMR

(25012MHz CD3CN) 120575 119 (t 3H J 70Hz CH

3) 126 129

137 141 [4s each 3H 2 times C(CH3)3] 238 252 [2m each 2H

(CH2)2] 312 (ddd 1H 1198696a6b 137Hz 119869

56a 81 Hz 1198696aNH 55HzH-6a) 336 (ddd 1H 119869

56b 52Hz 1198696bNH 64Hz H-6b) 354(q 2H J 70HzCH

3CH2N) 368 (t 2H J 59HzCH

2CH2N)

384 (ddd 1H H-5) 417 (dd 1H 11986934 79Hz 119869

45 19Hz H-4) 429 (dd 1H 119869

12 49Hz 11986923 25Hz H-2) 426 (t 2H J

59Hz CH2OCO) 457 (dd 1H H-3) 541 (d 1H H-1) 652

(bt 1H NH) 689 786 (AA1015840XX1015840 system 4H Ar-H-8 Ar-H-9 Ar-H-11 Ar-H-12) 791 831 (AA1015840XX1015840 system 4H Ar-H-2 Ar-H-3 Ar-H-5 Ar-H-6) 13C NMR (629MHz CD

3CN)

120575 124 (CH3) 245 252 262 263 [2 times C(CH

3)3] 300 309

[(CH2)2] 406 (C-6) 463 (CH

3CH2N) 494 (CH

2CH2N)

623 (CH2OCO) 669 (C-5) 714 (C-2) 715 (C-3) 722 (C-

4) 961 (C-1) 1093 1098 [2 times C(CH3)3] 1126 1233 1257

1269 (8 timesAr-CH) 1443 (Ar-C-7) 1484 (Ar-C-4) 1527 1577(Ar-C-1 Ar-C-10) 1724 1736 (2 times C=O) Anal Calcd forC32H41N5O10(65570) C 5862 H 630 N 1068 Found C

5860 H 628 N 1065

27 Preparation of Protected GAD 15 The condensationof azo dye 10 (151mg 0367mmol) and amine 5 (224mg0441mmol 12 eq) with 4-(46-dimethoxy-135-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM) [13](122mg 0441mmol 12 eq) in dry THF (4mL) wasperformed according to the procedure described above forthe preparation of 14 The flash chromatography over silicagel (19 hexane-EtOAc) of the crude reaction product led topure 15 (252mg 76 yield calculated from 10) as a red foam119877119891032 (EtOAc) 1H NMR (25012MHz CD

3CN) 120575 118 (t

3H J 70Hz CH3) 127 133 [2s each 6H 2 times C(CH

3)3]

137 142 [2s each 3H C(CH3)3] 244 255 [2m each 2H

(CH2)2] 343 346 (2s each 3H 2 times OCH

3) 311 (ddd 1H

11986951015840 61015840a 88Hz 11986961015840aNH 52Hz 11986961015840a61015840b 134Hz H-61015840a) 332 (dd1H 1198691101584021015840 80Hz 119869

2101584031015840 73Hz H-21015840) 351 (q 2H J 70Hz

CH3CH2N) 367 (m 2H J 60Hz CH

2CH2N) 370ndash375

(m 3H H-51015840 H-61015840b OH-21015840) 382 (dd 1H 11986945 52Hz 119869

3413Hz H-4) 394 (dd 1H 119869

3101584041015840 34Hz H-31015840) 400 (dd 1H

1198696a6b 81 Hz 11986956a 63Hz H-6a) 403 (dd 1H 119869

23 72Hz H-3)404ndash410 (m 2H H-41015840 H-6b) 422 (dt 1H 119869

56a = 11986956b63Hz H-5) 427 (t 2H J 60Hz CH

2OCO) 431 (d 1H H-

11015840) 435 (d 1H 11986912 64Hz H-1) 441 (dd 1H H-2) 668 (bt

1H NH) 685 768 (AA1015840XX1015840 system 4H Ar-H-8 Ar-H-9Ar-H-11 Ar-H-12) 788 829 (AA1015840XX1015840 system 4H Ar-H-2Ar-H-3 Ar-H-5 Ar-H-6) 13C NMR (629MHz CD

3CN)

120575 124 (CH3) 251 264 265 269 274 284 [3 times C(CH

3)3]

309 299 [(CH2)2] 409 (C-61015840) 462 (CH

3CH2N) 495

(OCH2CH2N) 560 580 (2 timesOCH

3) 623 (CH

2OCO) 660

(C-6) 746 (C-21015840) 726 (C-51015840) 750 (C-41015840) 774 (C-2) 776(C-5) 777 (C-4) 784 (C-3) 800 (C-31015840) 1041 (C-11015840) 1082

(C-1) 1092 1104 1106 [3 times C(CH3)3] 1126 1233 1257

1269 (8 times Ar-CH) 1442 (Ar-C-7) 1483 (Ar-C-4) 15271576 (Ar-C-1 Ar-C-10) 1723 1737 (2 times C=O) Anal Calcdfor C43H61N5O16

(90337) C 5713 H 680 N 775 FoundC 5711 H 677 N 772

28 Preparation of Deprotected GAD 16 A solution of 11(107 g 155mmol) in 90 aqueous CF

3COOH (70mL) was

stirred at room temperature until the starting material wascompletely disappeared (3 h TLC EtOAc) The red-violetsolution was concentrated under diminished pressure andrepeatedly coevaporated with toluene (5 times 30mL)The cruderesiduewas dissolved inEtOAc (100mL) andneutralizedwithsaturated aqueous NaHCO

3(20mL)The aqueous phase was

extracted with EtOAc (3 times 50mL) and the collected layerswere dried filtered and concentrated under diminishedpressure The residue was triturated with Et

2O and the red

residue was constituted (NMR) only by the azo dye 16(640mg 98 yield) as a mixture of 120572- and 120573-pyranoseanomers (NMR) in a ratio of 3 2 calculated on the basis ofthe relative C-1 signal intensities Compound 16 was a redsolid foam 119877

119891021 (91 EtOAc-MeOH) Selected 1H NMR

(20013MHz CD3OD) signals for both anomers 120575 106 (t

3H J 67Hz CH3) 248ndash230 [m 4H (CH

2)2] 673 764

(AA1015840XX1015840 system 4H Ar-H-8 Ar-H-9 Ar-H-11 Ar-H-12)754 (bd 1H Ar-H-6) 800 (dd 1H 119869

56 90Hz Ar-H-5) 840(d 1H 119869

35 22Hz Ar-H-3) 13CNMR (503MHz CD3OD) 120575

120572-pyranose 408 (C-6) 688 (C-5) 692 (C-4) 697 (C-2 C-3)938 (C-1) 120573-pyranose 407 (C-6) 691 (C-4) 725 (C-3) 730737 (C-2 C-5) 978 (C-1) cluster of signals for both anomers120575 125 (CH

3) 294ndash309 [(CH

2)2] 459 (CH

3CH2N) 489

(OCH2CH2N) 620 (CH

2OCO) 1122ndash1272 (Ar-CH) 1330

(Ar-C-2) 1439 (Ar-C-7) 1470 (Ar-C-4) 1526 1528 (Ar-C-1Ar-C-10) 1724 1732 (2 times C=O) Calcd for C

26H32ClN5O10

(61001) C 5119 H 529 N 1148 Found C 5117 H 528 N1145

29 Preparation of Deprotected GAD 17 Hydrolysis of 12(640mg 0682mmol) with 90 aqueous CF

3COOH (8mL)

was performed as described above for the preparation of 16After 2 h of stirring the red-violet solution was concentratedunder diminished pressure neutralized and extracted asdescribed above to give a red foam constituted (NMR) onlyby the azo dye 17 (485mg 92 yield) as a mixture of 120572- and120573-pyranose anomers (NMR) in the ratio of 3 2 calculated onthe basis of the relative C-1 signal intensities Compound 17was a red solid foam 119877

119891018 (82 EtOAc-MeOH) 120582max

49325 nm (MeOH) Selected 1H NMR (20013MHzCD3OD) 120575 120 (t 3H J 71 Hz CH

3 120572- and 120573-pyranose)

248 257 [2m each 2H (CH2)2 120572- and 120573-pyranose] 318

(dd 1H 11986912 78Hz 119869

23 90Hz H-2 120573-pyranose) 418 (d1H 1198691101584021015840 80Hz H-11015840 120572-pyranose) 420 (d 1H 119869

1101584021015840 78Hz

H-11015840 120573-pyranose) 425 (bt 2H J 64Hz CH2OCO 120572-

and 120573-pyranose) 431 (bt 2H J 66Hz CH2OCO 120572- and

120573-pyranose) 448 (d 1H H-1 120573-pyranose) 449ndash461 (mH-21015840 120572- and 120573-pyranose) 506 (d 1H 119869

12 37Hz H-1 120572-pyranose) 685 783 (AA1015840XX1015840 system 4H Ar-H-8 Ar-H-9

International Journal of Carbohydrate Chemistry 5

O

X

O

O

YZ

SuccinylationO

X

O

O

YZ

HN

O

O

OH

Me2C

NH2

(4) X = HZ = Y = O2CMe2(5) X = OGlcY = H Z = OH

(6) X = HZ = Y = O2CMe2(7) X = OGlcY = H Z = OH

Me2C

3 56-di-O-isopropylidene-aldehydo-D-glucose dimethyl acetalGlc = 2

Scheme 1 Protected aminosugars (4 and 5) and their monosuccinylamides (6 and 7)

Ar-H-11 Ar-H-12 120572- and 120573-pyranose) 772 (bd 1H Ar-H-6120572- and 120573-pyranose) 813 (bd 1H J 91Hz Ar-H-5 120572- and120573-pyranose) 832 (bd 1H Ar-H-3 120572- and 120573-pyranose) 13CNMR (629MHz CD

3OD) 120575 120572-pyranose 413 (C-61015840) 620

(C-6) 705 (C-41015840) 714 (C-5) 721 (C-21015840) 724 (C-2) 730(C-3) 734 (C-31015840) 760 (C-51015840) 811 (C-4) 937 (C-11015840) 1050(C-1) 120573-pyranose 412 (C-61015840) 628 (C-6) 704 (C-41015840) 723(C-21015840) 731 (C-31015840) 745 746 (C-3 C-2) 747 (C-5) 762(C-51015840) 805 (C-4) 981 (C-11015840) 1053 (C-1) cluster of signalsfor both anomers 120575 125 (CH

3) 303 313 [(CH

2)2] 467

(CH3CH2N) 500 (OCH

2CH2N) 629 (CH

2OCO) 1129ndash

1299 (7 times Ar-CH) 1347 (Ar-C-2) 1456 (Ar-C-7) 1486(Ar-C-4) 1536 1543 (Ar-C-1 Ar-C-10) 1744 1749 (2 timesC=O) Anal Calcd for C

32H42ClN5O15(77215) C 4978 H

548 N 907 Found C 4975 H 546 N 905

210 Preparation of Deprotected GAD 18 Thehydrolysis of 13(193mg 0316mmol) with 90 aqueous CF

3COOH (3mL)

was performed as described above for the preparation of 16After 2 h of stirring the red-violet solution was concentratedunder diminished pressure neutralized (saturated aqueousNaHCO

3) until the red-violet colour turned to yellow-

orange and extracted as described above to give a yellowfoam constituted (NMR) only by the azo dye 18 (160mg 95yield) Compound 18 was a mixture of 120572- and 120573-pyranoseanomers (NMR) in the ratio of 1 1 calculated on the basis ofthe relative C-1 signal intensities119877

119891019 (91 EtOAc-MeOH)

120582max 41125 nm (MeOH) Selected 1H NMR (20013MHzCD3OD) signals for both anomers 120575 121 (t 3H J 61 Hz

CH3) 258 [m 4H (CH

2)2] 683 (m 2H Ar-H-9 Ar-H-11)

735ndash750 (m 3H Ar-H-3 Ar-H-4 Ar-H-5) 775ndash783 (m 4HAr-H-2 Ar-H-6 Ar-H-8 Ar-H-12) 13C NMR (629MHzCD3OD) 120575 120572-pyranose 401 (C-6) 675 (C-5) 694 695

697 (C-2 C-3 C-4) 936 (C-1) 120573-pyranose 405 (C-6) 703(C-4) 721 (C-3) 731 741 (C-2 C-5) 982 (C-1) cluster ofsignals for both anomers 120575 119 (CH

3) 285 286 [(CH

2)2]

462 (CH3CH2N) 529 (OCH

2CH2N) 598 (CH

2OCO) 1111

1225 1257 1295 1299 (Ar-CH) 1432 (Ar-C-7) 1501 1530(Ar-C-1 Ar-C-10) 1740 1742 (2 times C=O) Anal Calcd for

C26H34N4O8(53057) C 5886 H 646 N 1056 Found C

5883 H 642 N 1053

3 Results and Discussion

In the search of new derivatives to be tested as new GADswe followed the same strategy used for the synthesis of thedi-estereal [4 5] (1) and diethereal [6] (2) compoundsWe were interested in preparing structures with differentfunctional groups at the attachment point with the linkerin order to evaluate the synthetic accessibility and at alater stage the effect of these changes both on the stabilityduring the dyeing process and on the tinctorial properties Toconstruct the amido-estereal mixed GADs we used appro-priately protected 6-amino-galactose derivatives in either thecondensation reaction with monosuccinyl-azo dye or aftertheir conversion into monosuccinyl derivatives This wouldallow us to study the two complementary strategies and toidentify the best pathway

Treatment of 4 [10] and 5 [8] with succinic anhydridein methanol (Scheme 1) afforded in good yields the cor-responding monosuccinyl derivatives 6 (76 yield) and 7(98 yield) that were utilized in the GAD synthesis via routeA (Scheme 2) Azo dyes 8ndash10 (Figure 2) were employed ascounterpart in the condensation reaction

In particular the known yellow azo dye (8) [12] and thecommercial Disperse Red 13 (9) were used in the preparationof GADs following route A (Scheme 2) while derivative10 prepared by succinylation of commercial alcoholic azodye Disperse Red 1 [4] was employed in the condensationreaction with the aminosugar derivatives 4 [10] and 5 [8](route B)

The coupling reactions were performed in THF withNN1015840-dicyclohexylcarbodiimide (DCC method a) or 4-(46-dimethoxy-135-triazin-2-yl)-4-methylmorpholinium chlo-ride (DMTMM method b) prepared according to Kun-ishima et al [13] from 2-chloro-46-dimethoxy-135-triazine(CDMT) andN-methylmorpholine (NMM) at room temper-ature The results obtained in the preparation of protectedGADs 11ndash15 are summarised in Table 1 The two possible

6 International Journal of Carbohydrate Chemistry

NRNR

NN

OR

OO

O OGlc

OO

OO O

OO

OOH

OGlc

OO

OO O

Route B

Route AR998400

OR998400998400

+6 or 7

R998400

OR998400998400

(9) R = NO2R998400= ClR998400998400

= H8( ) R = R998400

= R998400998400= H (11) R = NO2R

998400= ClR998400998400

= A(12) R = NO2R

998400= ClR998400998400

= B(13) R = R998400

= HR998400998400= A

OCO(CH2)2CONH-R

(10) R = CO(CH2)2COOH (14) R = C(15) R = D

O2NO2N

A = Me2CNHCO(CH2)2CO

B = Me2C

C = Me2C

D = Me2C

OH

NHCO(CH2)2CO

N=N

N=N N=N+4 or 5

N=N

Me2C Me2C

Scheme 2 Protected amido-ester GADs prepared through either method A or method B

NR

(9) R = NO2R998400= ClR998400998400

= H(10) R = NO2R

998400= HR998400998400

= CO(CH2)2COOH

8( ) R = R998400= R998400998400

= H

R998400

OR998400998400

N=N

Figure 2 Monoazo dyes 8-9 and monosuccinyl-azo dye 10

approaches gave comparable results and the desired productswere isolated in good to excellent yields

It is noteworthy that the succinyl derivatives 7 and 10could be used as crudes without affecting the outcome of thecondensation reaction In the case of protected compounds11ndash13 the final deprotected GADs 16ndash18 (Figure 3) wereobtained by simply removing the acetal protecting groups bymeans of acid hydrolysis as we previously reported [4ndash6] fortype 1 and type 2 derivatives (90 aqueous CF

3COOH room

temperature)Deprotected GADs were obtained in good yields (92ndash

98) as red (16-17) or yellow-orange (18) amorphousresidues constituted by mixtures of anomers (NMR analysis)

Isomeric forms of the 16ndash18 were identified by comparisonof their NMR data with those reported for analogous com-pounds (types 1-2) [4ndash6] The UV-Vis absorption spectra fora deprotected red GAD (17) and for the deprotected yellowGAD (18) were recorded in MeOH As for the previous twogenerations of GADs [4 5] the glycoconjugation process didnot affect the absorption properties of the dyes and 17 and18 were characterised by almost the same 120582max values of theparent not conjugated dyes (120582max around 495 nm for the redcompounds 9 12 and 17 and around 410 nm for the yellow-orange compounds 8 13 and 18)

4 Conclusions

In conclusions we presented the access to the third gen-eration of GADs exploring two complementary routes Theobtained compounds are characterized by different attach-ment points between the chromophore or the sugar and thelinker The presence of the amido bond could permit a novelsynthetic pathway to GADs for example by using enzymes[14] for the condensation reaction Detailed analysis of thestability and tinctorial properties of the third generation ofGADs are currently under investigation the results of whichwill be published in due course

International Journal of Carbohydrate Chemistry 7

Table 1 Preparation of amido-ester protected GADs

Entry Reactants Condensation system Condensation product (yield)Sugar moiety Dye moiety

1 6 9 Method A 11 (74)2 7 9 Method A 12 (82)3 6 8 Method A 13 (86)4 4 10 Method B 14 (95)5 5 10 Method B 15 (76)Method A DCC DMAP and THF method B DMTMM and THF

O

O

OO

HO

OH

NR

R998400

OR998400998400

Gal =

Lac =

NHCO(CH2)2CO-

(16) R = NO2R998400= ClR998400998400

= Gal(17) R = NO2R

998400= ClR998400998400

= Lac(18) R = R998400

= HR998400998400= Gal

NHCO(CH2)2CO-

OH

OHOH

HO

OH

HOOH

OH

OH

N=N

Figure 3 Conjugated deprotected GADs 16ndash18

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

References

[1] H-K Rouette Encyclopedia of Textile Finishing SpringerBerlin Germany 2001

[2] J H Hofenk de Graaf The Colourful Past Origins Chemistryand Identification of Natural Dyestuffs Abegg-Stitung Riggs-berg Switzerland Archetype Pubblications London UK 2004

[3] MNeamtu I SiminiceanuA Yediler andAKettrup ldquoKineticsof decolorization and mineralization of reactive azo dyes inaqueous solution by the UVH

2O2oxidationrdquo Dyes and Pig-

ments vol 53 no 2 pp 93ndash99 2002[4] G Bartalucci R Bianchini G Catelani F DrsquoAndrea and L

Guazzelli ldquoNaturalised dyes a simple straightforward syntheticroute to a new class of dyesmdashglycoazodyes (GADs)rdquo EuropeanJournal of Organic Chemistry no 4 pp 588ndash595 2007

[5] R Bianchini G Catelani R Cecconi et al ldquolsquoNaturalizationrsquo oftextile disperse dyes through glycoconjugation the case of abis(2-hydroxyethyl) group containing azo dyerdquo CarbohydrateResearch vol 343 no 12 pp 2067ndash2074 2008

[6] R Bianchini G Catelani R Cecconi et al ldquoEthereal glyco-conjugated azodyes (GADs) a new group of water-solublenaturalised dyesrdquo European Journal of Organic Chemistry no3 pp 444ndash454 2008

[7] A Porri R Baroncelli L Guglielminetti et al ldquoFusariumoxysporum degradation and detoxification of a new textile-glycoconjugate azo dye (GAD)rdquo Fungal Biology vol 115 no 1pp 30ndash37 2011

[8] J Isaad M Rolla and R Bianchini ldquoSynthesis of water-solublelarge naturalised dyes through double glycoconjugationrdquo Euro-pean Journal of Organic Chemistry no 17 pp 2748ndash2764 2009

[9] R Bianchini M Rolla J Isaad et al ldquoEfficient double glyco-conjugation to naturalize high molecular weight disperse dyesrdquoCarbohydrate Research vol 356 pp 104ndash109 2012

[10] D D Perrin W L F D Armarego and R Perrin Purificationof Laboratory Chemicals Pergamon Press Oxford UK 2ndedition 1980

[11] J Yang X Fu Q Jia et al ldquoStudies on the substrate specificity ofEscherichia coli galactokinaserdquoOrganic Letters vol 5 no 13 pp2223ndash2226 2003

[12] HWahl Y Arnould andM Simon ldquoDyes for cellulose acetateII Poly(hydroxyethyl)aniline dyesrdquo Bulletin de la Societe Chim-ique de France pp 366ndash369 1952

[13] M Kunishima C Kawachi F Iwasaki K Terao and STani ldquoSynthesis and characterization of 4-(46-dimethoxy-135-triazin-2-yl)- 4-methylmorpholinium chloriderdquo Tetrahe-dron Letters vol 40 no 29 pp 5327ndash5330 1999

[14] J Sharma D Batovska Y Kuwamori and Y Asano ldquoEnzymaticchemoselective synthesis of secondary-amide surfactant fromN-methylethanol aminerdquo Journal of Bioscience and Bioengineer-ing vol 100 no 6 pp 662ndash666 2005

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Chromatography Research International

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Quantum Chemistry

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CatalystsJournal of

2 International Journal of Carbohydrate Chemistry

Sugar DyeX YSpacer

(1) X = Y = OCO(2) X = Y = O(3) X = NHCOY = OCO

Figure 1 General structure of glycoconjugated azo dyes (GADs)

amino-61015840-deoxylactose units [8] Also glutamic acid wasused as the additional spacer in order to allow the double-conjugation [9] Presented here is an extension of our previ-ous results namely the synthesis of the third generation ofnaturalized GADs by conjugation of low molecular weightmonoazo dyes with either 6-amino-6-deoxy-d-galactose or61015840-amino-61015840-deoxylactose through mixed amido-ester con-nections (3)

2 Experimental

Optical rotations were measured with a Perkin-Elmer 241polarimeter at the sodiumD-line (589 nm) at 20plusmn2∘C using a1 dm cell 1HNMR and 13CNMR spectra were recorded witha Bruker AC 200 operating at 20013 (1H) and 503MHz (13C)or with a Bruker Avance II 250 spectrometer operating at25012 (1H) and 629MHz (13C) Spin resonances werereported as chemical shifts (120575) in part per million (ppm) andthe references to the residual peak of the solvent employed asfollows CDCl

3727 ppm (1HNMR) and 770 ppm (13CNMR

central band) CD3CN 194 ppm (1HNMR central band) and

128 ppm (13C NMR central band) and CD3OD 331 ppm

(1H NMR central band) and 490 ppm (13C NMR centralband) Coupling constants 119869 were reported in Hertz (Hz)The assignments were made when possible with the aidof DEPT HETCOR COSY and HSQC experiments and inthe case of anomeric mixtures referring to the differences inthe peak intensities and comparison with values for knownanalogous compounds UV-Vis spectra were recorded ona Cary-300 Agilent Technologies Cary Series UV-VisSpectrophotometer Elemental analyses were performed byCarlo Erba elemental analyzer MOD 1106 instrumentAll reactions were followed by TLC on Kieselgel 60 F

254

with detection by UV light andor with ethanolic 10phosphomolybdic or sulfuric acid and heating Kieselgel 60(E Merck 70ndash230 and 230ndash400 mesh resp) was used forcolumn and flash chromatography Solvents were dried andpurified by distillation according to standard procedure[10] and stored over 4 A molecular sieves activated for atleast 24 h at 200∘C Na

2SO4or MgSO

4was used as the

drying agent for solutions 6-Amino-6-deoxy-1234-di-O-isopropylidene-120572-d-galactopyranose (4) [11] 6-amino-6-deoxy-34-O-isopropylidene-120573-d-galactopyranosyl-(1rarr 4)-2356-di-O-isopropylidene-aldehydo-d-glucose dimethylacetal (5) [8] 2-[ethyl-(4-phenyldiazenyl)-phenyl-amino]-ethanol (8) [12] and 4-[2-ethyl-(4-[(4-nitrophenyl)dia-

zenyl]phenylamino)ethoxy]-4-oxobutanoic acid (10) [4]were prepared through literature methods

21 6-N-(3-Carboxy-propanoyl)-6-deoxy-1234-di-O-isopro-pylidene-120572-d-galactopyranose (6) A solution of 4 [11](260 g 100mmol) in MeOH (70mL) was treated withsuccinic anhydride (120 g 120mmol 12 eq) and stirred atroom temperature until the starting material was completelydisappeared (TLC 91 EtOAc-iPrOH) After 2 h Et

3N (3mL)

was added to the reaction mixture which was stirred for10min at room temperature and then was repeatedlycoevaporated with toluene (5 times 20mL) at diminishedpressure The resulting residue was dissolved into CH

2Cl2

(50mL) neutralized with AcOH (6mL) and washed withwater (25mL) and the aqueous phase was extracted withCH2Cl2(4 times 30mL) The combined organic layers were

dried (MgSO4) filtered and concentrated under diminished

pressure The crude residue (342 g) was subjected to flashchromatographic purification on silica gel (EtOAc) to givepure 6 as white foam (275 g 76 yield) [120572]D minus98 (119888 11CHCl

3) 119877119891050 (91 EtOAc-iPrOH) 1H NMR (20013MHz

CDCl3) 120575 129 131 138 143 [4s each 3H 2 times C(CH

3)3]

241ndash255 [m 4H (CH2)2] 316 (ddd 1H 1198696a6b 137Hz 1198696aNH

53Hz 11986956a 80Hz H-6a) 342 (ddd 1H 1198696bNH 64Hz

11986956b 47Hz H-6b) 386 (ddd 1H H-5) 419 (dd 1H 119869

3479Hz 119869

45 18Hz H-4) 431 (dd 1H 11986912 50Hz 119869

23 24HzH-2) 459 (dd 1H H-3) 543 (d 1H H-1) 680 (bt 1HNH) 13C NMR (503MHz CDCl

3) 120575 246 252 262 263

[2 times C(CH3)3] 302 310 [(CH

2)2] 408 (C-6) 669 (C-5)

714 716 722 (C-2 C-3 C-4) 971 (C-1) 1094 1098 [2 timesC(CH

3)3] 1738 1746 (2timesC=O) Anal Calcd for C

16H25NO8

(35937) C 5347 H 701 N 390 Found C 5344 H 699N 388

22 6-N-(3-Carboxy-propanoyl)-6-deoxy-34-O-isopropylid-ene-120573-d-galactopyranosyl-(1rarr 4)-2356-di-O-isopropylide-ne-aldehydo-d-glucose Dimethyl Acetal (7) A solution ofamine 5 [8] (100 g 197mmol) and succinic anhydride(216mg 216mmol 12 eq) in MeOH (40mL) was allowed toreact in the reaction conditions described for the preparationof 6 leading to the residue (117 g) constituted exclusively(13C NMR) by 7 (98 yield) An analytical sample of 7was obtained through flash chromatography over silica geleluting with 91 EtOAc-iPrOH Compound 7 was a whitefoam [120572]D +532 (119888 11 CHCl

3) 119877119891051 (91 EtOAc-iPrOH)

1H NMR (25012MHz CD3CN) 120575 129 134 [2s each 6H

2 times C(CH3)3] 139 143 [2s each 3H C(CH

3)3] 251 [m

4H (CH2)2] 344 349 (2s each 3H 2 times OCH

3) 313 (ddd

1H 11986951015840 61015840a 68Hz 11986961015840aNH 49Hz 11986961015840a61015840b 138Hz H-61015840a) 333(dd 1H 119869

1101584021015840 81 Hz 119869

2101584031015840 73Hz H-21015840) 367ndash380 (m 2H

H-51015840 H-61015840b) 384 (dd 1H 11986934 13Hz 119869

45 54Hz H-4)399 (dd 1H 119869

3101584041015840 32Hz H-31015840) 406 (m 3H H-3 H-6a

OH-21015840) 409 (dd 1H 1198694101584051015840 51 Hz H-41015840) 422 (m 2H H-5

H-6b) 433 (d 1H H-11015840) 436 (d 1H 11986912 64Hz H-1)

441 (dd 1H 11986923 71 Hz H-2) 685 (bt 1H NH) 13C NMR

(629MHz CD3CN) 120575 252 265 266 269 274 284 [3 times

C(CH3)3] 301 310 [(CH

2)2] 581 560 (2 times OCH

3) 411

International Journal of Carbohydrate Chemistry 3

(C-61015840) 661 (C-6) 746 (C-21015840) 725 (C-51015840) 750 (C-41015840) 774(C-2) 776 (C-5) 777 (C-4) 784 (C-3) 800 (C-31015840) 1040(C-11015840) 1082 (C-1) 1093 1104 1107 [3 times C(CH

3)3] 1736

1747 (2 times C=O) Anal Calcd for C27H45NO14

(60728) C5337 H 746 N 231 Found C 5335 H 743 N 229

23 Preparation of Protected GAD 11 A solution of 6(150 g 417mmol) and azo dye 9 (181 g 517mmol124 eq) in dry THF (50mL) was treated with NN1015840-dicyclohexylcarbodiimide (DDC) (103 g 50mmol 12 eq)and 4-dimethylaminopyridine (DMAP) (145mg 119mmol)and the solution was stirred at room temperature until thestarting material was completely disappeared (4 h TLCEtOAc) The reaction mixture was concentrated underdiminished pressure and the crude residue was dissolvedinto CH

2Cl2(70mL) and washed in the order with saturated

aqueous NaHCO3(3 times 30mL) and brine (30mL) The

organic phase was dried (Na2SO4) filtered and concentrated

under diminished pressure Purification of the crude residue(310 g) by flash chromatography over silica gel (23 hexane-EtOAc) gave pure 11 as a red foam (214 g 74 yield) 119877

119891

022 (23 hexane-EtOAc) 1H NMR (20013MHz CDCl3) 120575

127 (t 3H J 72Hz CH3) 132 133 145 148 [4s each 3H

2 times C(CH3)3] 265 248 [2m each 2H (CH

2)2] 320 (ddd

1H 1198696a6b 139Hz 11986956a 89Hz 1198696aNH 37Hz H-6a) 355 (q

2H J 72Hz CH3CH2N) 370 (t 2H J 62Hz OCH

2CH2N)

372 (ddd 1H 11986956b 35Hz 1198696bNH 72Hz H-6b) 387 (ddd

1H H-5) 419 (dd 1H 11986945 17Hz 119869

34 79Hz H-4) 431(dd 1H 119869

12 50Hz 11986923 25Hz H-2) 432 (t 2H J 62Hz

CH2OCO) 459 (dd 1H H-3) 551 (d 1H H-1) 598 (dd

1H NH) 779 (d 1H Ar-H-6) 687 796 (AA1015840XX1015840 system4H Ar-H-8 Ar-H-9 Ar-H-11 Ar-H-12) 816 (dd 1H 119869

5690Hz Ar-H-5) 840 (d 1H 119869

35 24Hz Ar-H-3) 13C NMR(503MHz CDCl

3) 120575 122 (CH

3) 243 249 259 260 [2 times

C(CH3)3] 293 306 [(CH

2)2] 400 (C-6) 458 (CH

3CH2N)

488 (OCH2CH2N) 613 (CH

2OCO) 663 (C-5) 705 (C-2)

706 (C-3) 716 (C-4) 961 (C-1) 1087 1094 [2 times C(CH3)3]

1115 1116 1179 1225 1259 1269 1269 (7 times Ar-CH)1339 (Ar-C-2) 1444 (Ar-C-7) 1471 (Ar-C-4) 1516 1530(Ar-C-1 Ar-C-10) 1713 1727 (2 times C=O) Anal Calcd forC32H40ClN5O10

(69014) C 5569 H 584 N 1015 FoundC 5566 H 583 N 1012

24 Preparation of Protected GAD 12 The condensationof 7 (150 g 247mmol) and azo dye 9 (106 g 305mmol124 eq) with NN1015840-dicyclohexylcarbodiimide (DDC)(630mg 305mmol) and 4-dimethylaminopyridine (DMAP)(90mg 073mmol) in dry THF (30mL) was performedaccording to the procedure described above for 11 The flashchromatography over silica gel of the crude product (14hexane-EtOAc) led to pure 12 (190 g 82 yield) as a redfoam 119877

119891027 (14 hexane-EtOAc) 120582max 49300 nm (MeOH)

1H NMR (25012MHz CD3CN) 120575 120 (t 3H J 71 Hz

CH3) 128 133 [2s each 6H 2 times C(CH

3)3] 137 142 [2s

each 3H C(CH3)3] 244 255 [2m each 2H (CH

2)2] 343

347 (2s each 3H 2 times OCH3) 309 (ddd 1H 11986951015840 61015840a 81 Hz

11986961015840aNH 55Hz 11986961015840a61015840b 138Hz H-61015840a) 330ndash341 (m 2H H-21015840

OH-21015840) 352 (q 2H J 71 Hz CH3CH2N) 360ndash378 (m

4H OCH2CH2N H-51015840 H-61015840b) 382 (dd 1H 119869

34 12Hz11986945 48Hz H-4) 390ndash412 (m 5H H-31015840 H-41015840 H-3 H-6aH-6b) 418 (m 1H H-5) 425 (t 2H J 61Hz CH

2OCO)

430 (d 1H 1198691101584021015840 82Hz H-11015840) 434 (d 1H 119869

12 65Hz H-1)440 (dd 1H 119869

23 71Hz H-2) 667 (bt 1H NH) 773 (d 1HAr-H-6) 686 785 (AA1015840XX1015840 system 4H Ar-H-8 Ar-H-9Ar-H-11 Ar-H-12) 815 (dd 1H 119869

56 90Hz Ar-H-5) 837 (d1H 11986935 24Hz Ar-H-3) 13C NMR (629MHz CD

3CN) 120575

124 (CH3) 251 265 266 269 274 284 [3 times C(CH

3)3]

291 309 [(CH2)2] 409 (C-61015840) 464 (CH

3CH2N) 495

(OCH2CH2N) 560 580 (2 times OCH

3) 661 (C-6) 623

(CH2OCO) 746 (C-21015840) 727 (C-51015840) 750 (C-41015840) 774 (C-2)

776 (C-5) 778 (C-4) 784 (C-3) 801 (C-31015840) 1040 (C-11015840)1082 (C-1) 1094 1106 1107 [3 times C(CH

3)3] 1127 1127 1188

1239 1268 1276 1277 (7 times Ar-CH) 1341 (Ar-C-2) 1448(Ar-C-7) 1482 (Ar-C-4) 1533 1538 (Ar-C-1 Ar-C-10)1723 1737 (2 times C=O) Anal Calcd for C

43H60ClN5O16

(93841) C 5504 H 644 N 746 Found C 5502 H 642N 743

25 Preparation of Protected GAD 13 A solution of 6 (10 g278mmol) azo dye 8 (950mg 352mmol 125 eq) NN1015840-dicyclohexylcarbodiimide (DDC) (688mg 334mmol) and4-dimethylaminopyridine (DMAP) (102mg 083mmol) indry THF (30mL) was allowed to react in the reactionconditions described for the preparation of 11The flash chro-matography over silica gel (11 hexane-EtOAc) afforded pure13 (147 g 86 yield) as a yellow foam 119877

119891031 (46 hexane-

EtOAc) 120582max 40700 nm (MeOH) 1H NMR (20013MHzCDCl

3) 120575 122 (t 3H J 70Hz CH

3) 130 133 144 148 [4s

each 3H 2 times C(CH3)3] 247 266 [2m each 2H (CH

2)2]

320 (ddd 1H 1198696a6b 140Hz 11986956a 90Hz 1198696aNH 38Hz H-

6a) 349 (q 2H J 70Hz CH3CH2N) 364 (t 2H J 62Hz

OCH2CH2N) 371 (ddd 1H 119869

56b 35Hz 1198696bNH 77Hz H-6b)387 (ddd 1H H-5) 418 (dd 1H 119869

34 79Hz 11986945 18Hz H-4)

430 (dd 1H 11986912 50Hz 119869

23 24Hz H-2) 428 (t 2H J 62HzCH2OCO) 457 (dd 1H H-3) 550 (d 1H H-1) 600 (dd 1H

NH) 678 (m 2H Ar-H-9 Ar-H-11) 737ndash751 (m 3H Ar-H-3 Ar-H-4 Ar-H-5) 781ndash790 (m 4H Ar-H-2 Ar-H-6 Ar-H-8 Ar-H-12) 13CNMR (503MHz CDCl

3) 120575 122 (CH

3) 243

249 258 259 [2 times C(CH3)3] 293 307 [(CH

2)2] 400 (C-

6) 455 (CH3CH2N) 487 (OCH

2CH2N) 615 (CH

2OCO)

663 (C-5) 705 (C-2) 707 (C-3) 716 (C-4) 962 (C-1) 10871094 [2 times C(CH

3)3] 1113 1221 1252 1264 1289 (Ar-CH)

1436 (Ar-C-7) 1499 1530 (Ar-C-1 Ar-C-10) 1714 1727 (2timesC=O) Anal Calcd for C

32H42N4O8(61070) C 6294 H

693 N 917 Found C 6291 H 690 N 915

26 Preparation of Protected GAD 14 A solution of azo dye10 (152mg 0367mmol) and amine 4 (114mg 0441mmol12 eq) in dry THF (4mL) was stirred at room tem-perature (10min) 4-(46-Dimethoxy-135-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM) [13] (122mg0441mmol 12 eq) was added and the mixture was stirredat room temperature until azo dye 10 was completely disap-peared (20 h TLC EtOAc) The reaction mixture was con-centrated under diminished pressure and the crude residue

4 International Journal of Carbohydrate Chemistry

was partitioned between water (10mL) and Et2O (10mL)

and the aqueous phase extracted with Et2O (3 times 10mL) The

collected organic phases were dried (Na2SO4) filtered and

concentrated under diminished pressure Purification of thecrude residue (310 g) by flash chromatography over silica gel(14 hexane-EtOAc) gave pure 14 as a red foam solid (230mg95 yield calculated from 10) 119877

119891045 (EtOAc) 1H NMR

(25012MHz CD3CN) 120575 119 (t 3H J 70Hz CH

3) 126 129

137 141 [4s each 3H 2 times C(CH3)3] 238 252 [2m each 2H

(CH2)2] 312 (ddd 1H 1198696a6b 137Hz 119869

56a 81 Hz 1198696aNH 55HzH-6a) 336 (ddd 1H 119869

56b 52Hz 1198696bNH 64Hz H-6b) 354(q 2H J 70HzCH

3CH2N) 368 (t 2H J 59HzCH

2CH2N)

384 (ddd 1H H-5) 417 (dd 1H 11986934 79Hz 119869

45 19Hz H-4) 429 (dd 1H 119869

12 49Hz 11986923 25Hz H-2) 426 (t 2H J

59Hz CH2OCO) 457 (dd 1H H-3) 541 (d 1H H-1) 652

(bt 1H NH) 689 786 (AA1015840XX1015840 system 4H Ar-H-8 Ar-H-9 Ar-H-11 Ar-H-12) 791 831 (AA1015840XX1015840 system 4H Ar-H-2 Ar-H-3 Ar-H-5 Ar-H-6) 13C NMR (629MHz CD

3CN)

120575 124 (CH3) 245 252 262 263 [2 times C(CH

3)3] 300 309

[(CH2)2] 406 (C-6) 463 (CH

3CH2N) 494 (CH

2CH2N)

623 (CH2OCO) 669 (C-5) 714 (C-2) 715 (C-3) 722 (C-

4) 961 (C-1) 1093 1098 [2 times C(CH3)3] 1126 1233 1257

1269 (8 timesAr-CH) 1443 (Ar-C-7) 1484 (Ar-C-4) 1527 1577(Ar-C-1 Ar-C-10) 1724 1736 (2 times C=O) Anal Calcd forC32H41N5O10(65570) C 5862 H 630 N 1068 Found C

5860 H 628 N 1065

27 Preparation of Protected GAD 15 The condensationof azo dye 10 (151mg 0367mmol) and amine 5 (224mg0441mmol 12 eq) with 4-(46-dimethoxy-135-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM) [13](122mg 0441mmol 12 eq) in dry THF (4mL) wasperformed according to the procedure described above forthe preparation of 14 The flash chromatography over silicagel (19 hexane-EtOAc) of the crude reaction product led topure 15 (252mg 76 yield calculated from 10) as a red foam119877119891032 (EtOAc) 1H NMR (25012MHz CD

3CN) 120575 118 (t

3H J 70Hz CH3) 127 133 [2s each 6H 2 times C(CH

3)3]

137 142 [2s each 3H C(CH3)3] 244 255 [2m each 2H

(CH2)2] 343 346 (2s each 3H 2 times OCH

3) 311 (ddd 1H

11986951015840 61015840a 88Hz 11986961015840aNH 52Hz 11986961015840a61015840b 134Hz H-61015840a) 332 (dd1H 1198691101584021015840 80Hz 119869

2101584031015840 73Hz H-21015840) 351 (q 2H J 70Hz

CH3CH2N) 367 (m 2H J 60Hz CH

2CH2N) 370ndash375

(m 3H H-51015840 H-61015840b OH-21015840) 382 (dd 1H 11986945 52Hz 119869

3413Hz H-4) 394 (dd 1H 119869

3101584041015840 34Hz H-31015840) 400 (dd 1H

1198696a6b 81 Hz 11986956a 63Hz H-6a) 403 (dd 1H 119869

23 72Hz H-3)404ndash410 (m 2H H-41015840 H-6b) 422 (dt 1H 119869

56a = 11986956b63Hz H-5) 427 (t 2H J 60Hz CH

2OCO) 431 (d 1H H-

11015840) 435 (d 1H 11986912 64Hz H-1) 441 (dd 1H H-2) 668 (bt

1H NH) 685 768 (AA1015840XX1015840 system 4H Ar-H-8 Ar-H-9Ar-H-11 Ar-H-12) 788 829 (AA1015840XX1015840 system 4H Ar-H-2Ar-H-3 Ar-H-5 Ar-H-6) 13C NMR (629MHz CD

3CN)

120575 124 (CH3) 251 264 265 269 274 284 [3 times C(CH

3)3]

309 299 [(CH2)2] 409 (C-61015840) 462 (CH

3CH2N) 495

(OCH2CH2N) 560 580 (2 timesOCH

3) 623 (CH

2OCO) 660

(C-6) 746 (C-21015840) 726 (C-51015840) 750 (C-41015840) 774 (C-2) 776(C-5) 777 (C-4) 784 (C-3) 800 (C-31015840) 1041 (C-11015840) 1082

(C-1) 1092 1104 1106 [3 times C(CH3)3] 1126 1233 1257

1269 (8 times Ar-CH) 1442 (Ar-C-7) 1483 (Ar-C-4) 15271576 (Ar-C-1 Ar-C-10) 1723 1737 (2 times C=O) Anal Calcdfor C43H61N5O16

(90337) C 5713 H 680 N 775 FoundC 5711 H 677 N 772

28 Preparation of Deprotected GAD 16 A solution of 11(107 g 155mmol) in 90 aqueous CF

3COOH (70mL) was

stirred at room temperature until the starting material wascompletely disappeared (3 h TLC EtOAc) The red-violetsolution was concentrated under diminished pressure andrepeatedly coevaporated with toluene (5 times 30mL)The cruderesiduewas dissolved inEtOAc (100mL) andneutralizedwithsaturated aqueous NaHCO

3(20mL)The aqueous phase was

extracted with EtOAc (3 times 50mL) and the collected layerswere dried filtered and concentrated under diminishedpressure The residue was triturated with Et

2O and the red

residue was constituted (NMR) only by the azo dye 16(640mg 98 yield) as a mixture of 120572- and 120573-pyranoseanomers (NMR) in a ratio of 3 2 calculated on the basis ofthe relative C-1 signal intensities Compound 16 was a redsolid foam 119877

119891021 (91 EtOAc-MeOH) Selected 1H NMR

(20013MHz CD3OD) signals for both anomers 120575 106 (t

3H J 67Hz CH3) 248ndash230 [m 4H (CH

2)2] 673 764

(AA1015840XX1015840 system 4H Ar-H-8 Ar-H-9 Ar-H-11 Ar-H-12)754 (bd 1H Ar-H-6) 800 (dd 1H 119869

56 90Hz Ar-H-5) 840(d 1H 119869

35 22Hz Ar-H-3) 13CNMR (503MHz CD3OD) 120575

120572-pyranose 408 (C-6) 688 (C-5) 692 (C-4) 697 (C-2 C-3)938 (C-1) 120573-pyranose 407 (C-6) 691 (C-4) 725 (C-3) 730737 (C-2 C-5) 978 (C-1) cluster of signals for both anomers120575 125 (CH

3) 294ndash309 [(CH

2)2] 459 (CH

3CH2N) 489

(OCH2CH2N) 620 (CH

2OCO) 1122ndash1272 (Ar-CH) 1330

(Ar-C-2) 1439 (Ar-C-7) 1470 (Ar-C-4) 1526 1528 (Ar-C-1Ar-C-10) 1724 1732 (2 times C=O) Calcd for C

26H32ClN5O10

(61001) C 5119 H 529 N 1148 Found C 5117 H 528 N1145

29 Preparation of Deprotected GAD 17 Hydrolysis of 12(640mg 0682mmol) with 90 aqueous CF

3COOH (8mL)

was performed as described above for the preparation of 16After 2 h of stirring the red-violet solution was concentratedunder diminished pressure neutralized and extracted asdescribed above to give a red foam constituted (NMR) onlyby the azo dye 17 (485mg 92 yield) as a mixture of 120572- and120573-pyranose anomers (NMR) in the ratio of 3 2 calculated onthe basis of the relative C-1 signal intensities Compound 17was a red solid foam 119877

119891018 (82 EtOAc-MeOH) 120582max

49325 nm (MeOH) Selected 1H NMR (20013MHzCD3OD) 120575 120 (t 3H J 71 Hz CH

3 120572- and 120573-pyranose)

248 257 [2m each 2H (CH2)2 120572- and 120573-pyranose] 318

(dd 1H 11986912 78Hz 119869

23 90Hz H-2 120573-pyranose) 418 (d1H 1198691101584021015840 80Hz H-11015840 120572-pyranose) 420 (d 1H 119869

1101584021015840 78Hz

H-11015840 120573-pyranose) 425 (bt 2H J 64Hz CH2OCO 120572-

and 120573-pyranose) 431 (bt 2H J 66Hz CH2OCO 120572- and

120573-pyranose) 448 (d 1H H-1 120573-pyranose) 449ndash461 (mH-21015840 120572- and 120573-pyranose) 506 (d 1H 119869

12 37Hz H-1 120572-pyranose) 685 783 (AA1015840XX1015840 system 4H Ar-H-8 Ar-H-9

International Journal of Carbohydrate Chemistry 5

O

X

O

O

YZ

SuccinylationO

X

O

O

YZ

HN

O

O

OH

Me2C

NH2

(4) X = HZ = Y = O2CMe2(5) X = OGlcY = H Z = OH

(6) X = HZ = Y = O2CMe2(7) X = OGlcY = H Z = OH

Me2C

3 56-di-O-isopropylidene-aldehydo-D-glucose dimethyl acetalGlc = 2

Scheme 1 Protected aminosugars (4 and 5) and their monosuccinylamides (6 and 7)

Ar-H-11 Ar-H-12 120572- and 120573-pyranose) 772 (bd 1H Ar-H-6120572- and 120573-pyranose) 813 (bd 1H J 91Hz Ar-H-5 120572- and120573-pyranose) 832 (bd 1H Ar-H-3 120572- and 120573-pyranose) 13CNMR (629MHz CD

3OD) 120575 120572-pyranose 413 (C-61015840) 620

(C-6) 705 (C-41015840) 714 (C-5) 721 (C-21015840) 724 (C-2) 730(C-3) 734 (C-31015840) 760 (C-51015840) 811 (C-4) 937 (C-11015840) 1050(C-1) 120573-pyranose 412 (C-61015840) 628 (C-6) 704 (C-41015840) 723(C-21015840) 731 (C-31015840) 745 746 (C-3 C-2) 747 (C-5) 762(C-51015840) 805 (C-4) 981 (C-11015840) 1053 (C-1) cluster of signalsfor both anomers 120575 125 (CH

3) 303 313 [(CH

2)2] 467

(CH3CH2N) 500 (OCH

2CH2N) 629 (CH

2OCO) 1129ndash

1299 (7 times Ar-CH) 1347 (Ar-C-2) 1456 (Ar-C-7) 1486(Ar-C-4) 1536 1543 (Ar-C-1 Ar-C-10) 1744 1749 (2 timesC=O) Anal Calcd for C

32H42ClN5O15(77215) C 4978 H

548 N 907 Found C 4975 H 546 N 905

210 Preparation of Deprotected GAD 18 Thehydrolysis of 13(193mg 0316mmol) with 90 aqueous CF

3COOH (3mL)

was performed as described above for the preparation of 16After 2 h of stirring the red-violet solution was concentratedunder diminished pressure neutralized (saturated aqueousNaHCO

3) until the red-violet colour turned to yellow-

orange and extracted as described above to give a yellowfoam constituted (NMR) only by the azo dye 18 (160mg 95yield) Compound 18 was a mixture of 120572- and 120573-pyranoseanomers (NMR) in the ratio of 1 1 calculated on the basis ofthe relative C-1 signal intensities119877

119891019 (91 EtOAc-MeOH)

120582max 41125 nm (MeOH) Selected 1H NMR (20013MHzCD3OD) signals for both anomers 120575 121 (t 3H J 61 Hz

CH3) 258 [m 4H (CH

2)2] 683 (m 2H Ar-H-9 Ar-H-11)

735ndash750 (m 3H Ar-H-3 Ar-H-4 Ar-H-5) 775ndash783 (m 4HAr-H-2 Ar-H-6 Ar-H-8 Ar-H-12) 13C NMR (629MHzCD3OD) 120575 120572-pyranose 401 (C-6) 675 (C-5) 694 695

697 (C-2 C-3 C-4) 936 (C-1) 120573-pyranose 405 (C-6) 703(C-4) 721 (C-3) 731 741 (C-2 C-5) 982 (C-1) cluster ofsignals for both anomers 120575 119 (CH

3) 285 286 [(CH

2)2]

462 (CH3CH2N) 529 (OCH

2CH2N) 598 (CH

2OCO) 1111

1225 1257 1295 1299 (Ar-CH) 1432 (Ar-C-7) 1501 1530(Ar-C-1 Ar-C-10) 1740 1742 (2 times C=O) Anal Calcd for

C26H34N4O8(53057) C 5886 H 646 N 1056 Found C

5883 H 642 N 1053

3 Results and Discussion

In the search of new derivatives to be tested as new GADswe followed the same strategy used for the synthesis of thedi-estereal [4 5] (1) and diethereal [6] (2) compoundsWe were interested in preparing structures with differentfunctional groups at the attachment point with the linkerin order to evaluate the synthetic accessibility and at alater stage the effect of these changes both on the stabilityduring the dyeing process and on the tinctorial properties Toconstruct the amido-estereal mixed GADs we used appro-priately protected 6-amino-galactose derivatives in either thecondensation reaction with monosuccinyl-azo dye or aftertheir conversion into monosuccinyl derivatives This wouldallow us to study the two complementary strategies and toidentify the best pathway

Treatment of 4 [10] and 5 [8] with succinic anhydridein methanol (Scheme 1) afforded in good yields the cor-responding monosuccinyl derivatives 6 (76 yield) and 7(98 yield) that were utilized in the GAD synthesis via routeA (Scheme 2) Azo dyes 8ndash10 (Figure 2) were employed ascounterpart in the condensation reaction

In particular the known yellow azo dye (8) [12] and thecommercial Disperse Red 13 (9) were used in the preparationof GADs following route A (Scheme 2) while derivative10 prepared by succinylation of commercial alcoholic azodye Disperse Red 1 [4] was employed in the condensationreaction with the aminosugar derivatives 4 [10] and 5 [8](route B)

The coupling reactions were performed in THF withNN1015840-dicyclohexylcarbodiimide (DCC method a) or 4-(46-dimethoxy-135-triazin-2-yl)-4-methylmorpholinium chlo-ride (DMTMM method b) prepared according to Kun-ishima et al [13] from 2-chloro-46-dimethoxy-135-triazine(CDMT) andN-methylmorpholine (NMM) at room temper-ature The results obtained in the preparation of protectedGADs 11ndash15 are summarised in Table 1 The two possible

6 International Journal of Carbohydrate Chemistry

NRNR

NN

OR

OO

O OGlc

OO

OO O

OO

OOH

OGlc

OO

OO O

Route B

Route AR998400

OR998400998400

+6 or 7

R998400

OR998400998400

(9) R = NO2R998400= ClR998400998400

= H8( ) R = R998400

= R998400998400= H (11) R = NO2R

998400= ClR998400998400

= A(12) R = NO2R

998400= ClR998400998400

= B(13) R = R998400

= HR998400998400= A

OCO(CH2)2CONH-R

(10) R = CO(CH2)2COOH (14) R = C(15) R = D

O2NO2N

A = Me2CNHCO(CH2)2CO

B = Me2C

C = Me2C

D = Me2C

OH

NHCO(CH2)2CO

N=N

N=N N=N+4 or 5

N=N

Me2C Me2C

Scheme 2 Protected amido-ester GADs prepared through either method A or method B

NR

(9) R = NO2R998400= ClR998400998400

= H(10) R = NO2R

998400= HR998400998400

= CO(CH2)2COOH

8( ) R = R998400= R998400998400

= H

R998400

OR998400998400

N=N

Figure 2 Monoazo dyes 8-9 and monosuccinyl-azo dye 10

approaches gave comparable results and the desired productswere isolated in good to excellent yields

It is noteworthy that the succinyl derivatives 7 and 10could be used as crudes without affecting the outcome of thecondensation reaction In the case of protected compounds11ndash13 the final deprotected GADs 16ndash18 (Figure 3) wereobtained by simply removing the acetal protecting groups bymeans of acid hydrolysis as we previously reported [4ndash6] fortype 1 and type 2 derivatives (90 aqueous CF

3COOH room

temperature)Deprotected GADs were obtained in good yields (92ndash

98) as red (16-17) or yellow-orange (18) amorphousresidues constituted by mixtures of anomers (NMR analysis)

Isomeric forms of the 16ndash18 were identified by comparisonof their NMR data with those reported for analogous com-pounds (types 1-2) [4ndash6] The UV-Vis absorption spectra fora deprotected red GAD (17) and for the deprotected yellowGAD (18) were recorded in MeOH As for the previous twogenerations of GADs [4 5] the glycoconjugation process didnot affect the absorption properties of the dyes and 17 and18 were characterised by almost the same 120582max values of theparent not conjugated dyes (120582max around 495 nm for the redcompounds 9 12 and 17 and around 410 nm for the yellow-orange compounds 8 13 and 18)

4 Conclusions

In conclusions we presented the access to the third gen-eration of GADs exploring two complementary routes Theobtained compounds are characterized by different attach-ment points between the chromophore or the sugar and thelinker The presence of the amido bond could permit a novelsynthetic pathway to GADs for example by using enzymes[14] for the condensation reaction Detailed analysis of thestability and tinctorial properties of the third generation ofGADs are currently under investigation the results of whichwill be published in due course

International Journal of Carbohydrate Chemistry 7

Table 1 Preparation of amido-ester protected GADs

Entry Reactants Condensation system Condensation product (yield)Sugar moiety Dye moiety

1 6 9 Method A 11 (74)2 7 9 Method A 12 (82)3 6 8 Method A 13 (86)4 4 10 Method B 14 (95)5 5 10 Method B 15 (76)Method A DCC DMAP and THF method B DMTMM and THF

O

O

OO

HO

OH

NR

R998400

OR998400998400

Gal =

Lac =

NHCO(CH2)2CO-

(16) R = NO2R998400= ClR998400998400

= Gal(17) R = NO2R

998400= ClR998400998400

= Lac(18) R = R998400

= HR998400998400= Gal

NHCO(CH2)2CO-

OH

OHOH

HO

OH

HOOH

OH

OH

N=N

Figure 3 Conjugated deprotected GADs 16ndash18

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

References

[1] H-K Rouette Encyclopedia of Textile Finishing SpringerBerlin Germany 2001

[2] J H Hofenk de Graaf The Colourful Past Origins Chemistryand Identification of Natural Dyestuffs Abegg-Stitung Riggs-berg Switzerland Archetype Pubblications London UK 2004

[3] MNeamtu I SiminiceanuA Yediler andAKettrup ldquoKineticsof decolorization and mineralization of reactive azo dyes inaqueous solution by the UVH

2O2oxidationrdquo Dyes and Pig-

ments vol 53 no 2 pp 93ndash99 2002[4] G Bartalucci R Bianchini G Catelani F DrsquoAndrea and L

Guazzelli ldquoNaturalised dyes a simple straightforward syntheticroute to a new class of dyesmdashglycoazodyes (GADs)rdquo EuropeanJournal of Organic Chemistry no 4 pp 588ndash595 2007

[5] R Bianchini G Catelani R Cecconi et al ldquolsquoNaturalizationrsquo oftextile disperse dyes through glycoconjugation the case of abis(2-hydroxyethyl) group containing azo dyerdquo CarbohydrateResearch vol 343 no 12 pp 2067ndash2074 2008

[6] R Bianchini G Catelani R Cecconi et al ldquoEthereal glyco-conjugated azodyes (GADs) a new group of water-solublenaturalised dyesrdquo European Journal of Organic Chemistry no3 pp 444ndash454 2008

[7] A Porri R Baroncelli L Guglielminetti et al ldquoFusariumoxysporum degradation and detoxification of a new textile-glycoconjugate azo dye (GAD)rdquo Fungal Biology vol 115 no 1pp 30ndash37 2011

[8] J Isaad M Rolla and R Bianchini ldquoSynthesis of water-solublelarge naturalised dyes through double glycoconjugationrdquo Euro-pean Journal of Organic Chemistry no 17 pp 2748ndash2764 2009

[9] R Bianchini M Rolla J Isaad et al ldquoEfficient double glyco-conjugation to naturalize high molecular weight disperse dyesrdquoCarbohydrate Research vol 356 pp 104ndash109 2012

[10] D D Perrin W L F D Armarego and R Perrin Purificationof Laboratory Chemicals Pergamon Press Oxford UK 2ndedition 1980

[11] J Yang X Fu Q Jia et al ldquoStudies on the substrate specificity ofEscherichia coli galactokinaserdquoOrganic Letters vol 5 no 13 pp2223ndash2226 2003

[12] HWahl Y Arnould andM Simon ldquoDyes for cellulose acetateII Poly(hydroxyethyl)aniline dyesrdquo Bulletin de la Societe Chim-ique de France pp 366ndash369 1952

[13] M Kunishima C Kawachi F Iwasaki K Terao and STani ldquoSynthesis and characterization of 4-(46-dimethoxy-135-triazin-2-yl)- 4-methylmorpholinium chloriderdquo Tetrahe-dron Letters vol 40 no 29 pp 5327ndash5330 1999

[14] J Sharma D Batovska Y Kuwamori and Y Asano ldquoEnzymaticchemoselective synthesis of secondary-amide surfactant fromN-methylethanol aminerdquo Journal of Bioscience and Bioengineer-ing vol 100 no 6 pp 662ndash666 2005

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International Journal of

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CatalystsJournal of

International Journal of Carbohydrate Chemistry 3

(C-61015840) 661 (C-6) 746 (C-21015840) 725 (C-51015840) 750 (C-41015840) 774(C-2) 776 (C-5) 777 (C-4) 784 (C-3) 800 (C-31015840) 1040(C-11015840) 1082 (C-1) 1093 1104 1107 [3 times C(CH

3)3] 1736

1747 (2 times C=O) Anal Calcd for C27H45NO14

(60728) C5337 H 746 N 231 Found C 5335 H 743 N 229

23 Preparation of Protected GAD 11 A solution of 6(150 g 417mmol) and azo dye 9 (181 g 517mmol124 eq) in dry THF (50mL) was treated with NN1015840-dicyclohexylcarbodiimide (DDC) (103 g 50mmol 12 eq)and 4-dimethylaminopyridine (DMAP) (145mg 119mmol)and the solution was stirred at room temperature until thestarting material was completely disappeared (4 h TLCEtOAc) The reaction mixture was concentrated underdiminished pressure and the crude residue was dissolvedinto CH

2Cl2(70mL) and washed in the order with saturated

aqueous NaHCO3(3 times 30mL) and brine (30mL) The

organic phase was dried (Na2SO4) filtered and concentrated

under diminished pressure Purification of the crude residue(310 g) by flash chromatography over silica gel (23 hexane-EtOAc) gave pure 11 as a red foam (214 g 74 yield) 119877

119891

022 (23 hexane-EtOAc) 1H NMR (20013MHz CDCl3) 120575

127 (t 3H J 72Hz CH3) 132 133 145 148 [4s each 3H

2 times C(CH3)3] 265 248 [2m each 2H (CH

2)2] 320 (ddd

1H 1198696a6b 139Hz 11986956a 89Hz 1198696aNH 37Hz H-6a) 355 (q

2H J 72Hz CH3CH2N) 370 (t 2H J 62Hz OCH

2CH2N)

372 (ddd 1H 11986956b 35Hz 1198696bNH 72Hz H-6b) 387 (ddd

1H H-5) 419 (dd 1H 11986945 17Hz 119869

34 79Hz H-4) 431(dd 1H 119869

12 50Hz 11986923 25Hz H-2) 432 (t 2H J 62Hz

CH2OCO) 459 (dd 1H H-3) 551 (d 1H H-1) 598 (dd

1H NH) 779 (d 1H Ar-H-6) 687 796 (AA1015840XX1015840 system4H Ar-H-8 Ar-H-9 Ar-H-11 Ar-H-12) 816 (dd 1H 119869

5690Hz Ar-H-5) 840 (d 1H 119869

35 24Hz Ar-H-3) 13C NMR(503MHz CDCl

3) 120575 122 (CH

3) 243 249 259 260 [2 times

C(CH3)3] 293 306 [(CH

2)2] 400 (C-6) 458 (CH

3CH2N)

488 (OCH2CH2N) 613 (CH

2OCO) 663 (C-5) 705 (C-2)

706 (C-3) 716 (C-4) 961 (C-1) 1087 1094 [2 times C(CH3)3]

1115 1116 1179 1225 1259 1269 1269 (7 times Ar-CH)1339 (Ar-C-2) 1444 (Ar-C-7) 1471 (Ar-C-4) 1516 1530(Ar-C-1 Ar-C-10) 1713 1727 (2 times C=O) Anal Calcd forC32H40ClN5O10

(69014) C 5569 H 584 N 1015 FoundC 5566 H 583 N 1012

24 Preparation of Protected GAD 12 The condensationof 7 (150 g 247mmol) and azo dye 9 (106 g 305mmol124 eq) with NN1015840-dicyclohexylcarbodiimide (DDC)(630mg 305mmol) and 4-dimethylaminopyridine (DMAP)(90mg 073mmol) in dry THF (30mL) was performedaccording to the procedure described above for 11 The flashchromatography over silica gel of the crude product (14hexane-EtOAc) led to pure 12 (190 g 82 yield) as a redfoam 119877

119891027 (14 hexane-EtOAc) 120582max 49300 nm (MeOH)

1H NMR (25012MHz CD3CN) 120575 120 (t 3H J 71 Hz

CH3) 128 133 [2s each 6H 2 times C(CH

3)3] 137 142 [2s

each 3H C(CH3)3] 244 255 [2m each 2H (CH

2)2] 343

347 (2s each 3H 2 times OCH3) 309 (ddd 1H 11986951015840 61015840a 81 Hz

11986961015840aNH 55Hz 11986961015840a61015840b 138Hz H-61015840a) 330ndash341 (m 2H H-21015840

OH-21015840) 352 (q 2H J 71 Hz CH3CH2N) 360ndash378 (m

4H OCH2CH2N H-51015840 H-61015840b) 382 (dd 1H 119869

34 12Hz11986945 48Hz H-4) 390ndash412 (m 5H H-31015840 H-41015840 H-3 H-6aH-6b) 418 (m 1H H-5) 425 (t 2H J 61Hz CH

2OCO)

430 (d 1H 1198691101584021015840 82Hz H-11015840) 434 (d 1H 119869

12 65Hz H-1)440 (dd 1H 119869

23 71Hz H-2) 667 (bt 1H NH) 773 (d 1HAr-H-6) 686 785 (AA1015840XX1015840 system 4H Ar-H-8 Ar-H-9Ar-H-11 Ar-H-12) 815 (dd 1H 119869

56 90Hz Ar-H-5) 837 (d1H 11986935 24Hz Ar-H-3) 13C NMR (629MHz CD

3CN) 120575

124 (CH3) 251 265 266 269 274 284 [3 times C(CH

3)3]

291 309 [(CH2)2] 409 (C-61015840) 464 (CH

3CH2N) 495

(OCH2CH2N) 560 580 (2 times OCH

3) 661 (C-6) 623

(CH2OCO) 746 (C-21015840) 727 (C-51015840) 750 (C-41015840) 774 (C-2)

776 (C-5) 778 (C-4) 784 (C-3) 801 (C-31015840) 1040 (C-11015840)1082 (C-1) 1094 1106 1107 [3 times C(CH

3)3] 1127 1127 1188

1239 1268 1276 1277 (7 times Ar-CH) 1341 (Ar-C-2) 1448(Ar-C-7) 1482 (Ar-C-4) 1533 1538 (Ar-C-1 Ar-C-10)1723 1737 (2 times C=O) Anal Calcd for C

43H60ClN5O16

(93841) C 5504 H 644 N 746 Found C 5502 H 642N 743

25 Preparation of Protected GAD 13 A solution of 6 (10 g278mmol) azo dye 8 (950mg 352mmol 125 eq) NN1015840-dicyclohexylcarbodiimide (DDC) (688mg 334mmol) and4-dimethylaminopyridine (DMAP) (102mg 083mmol) indry THF (30mL) was allowed to react in the reactionconditions described for the preparation of 11The flash chro-matography over silica gel (11 hexane-EtOAc) afforded pure13 (147 g 86 yield) as a yellow foam 119877

119891031 (46 hexane-

EtOAc) 120582max 40700 nm (MeOH) 1H NMR (20013MHzCDCl

3) 120575 122 (t 3H J 70Hz CH

3) 130 133 144 148 [4s

each 3H 2 times C(CH3)3] 247 266 [2m each 2H (CH

2)2]

320 (ddd 1H 1198696a6b 140Hz 11986956a 90Hz 1198696aNH 38Hz H-

6a) 349 (q 2H J 70Hz CH3CH2N) 364 (t 2H J 62Hz

OCH2CH2N) 371 (ddd 1H 119869

56b 35Hz 1198696bNH 77Hz H-6b)387 (ddd 1H H-5) 418 (dd 1H 119869

34 79Hz 11986945 18Hz H-4)

430 (dd 1H 11986912 50Hz 119869

23 24Hz H-2) 428 (t 2H J 62HzCH2OCO) 457 (dd 1H H-3) 550 (d 1H H-1) 600 (dd 1H

NH) 678 (m 2H Ar-H-9 Ar-H-11) 737ndash751 (m 3H Ar-H-3 Ar-H-4 Ar-H-5) 781ndash790 (m 4H Ar-H-2 Ar-H-6 Ar-H-8 Ar-H-12) 13CNMR (503MHz CDCl

3) 120575 122 (CH

3) 243

249 258 259 [2 times C(CH3)3] 293 307 [(CH

2)2] 400 (C-

6) 455 (CH3CH2N) 487 (OCH

2CH2N) 615 (CH

2OCO)

663 (C-5) 705 (C-2) 707 (C-3) 716 (C-4) 962 (C-1) 10871094 [2 times C(CH

3)3] 1113 1221 1252 1264 1289 (Ar-CH)

1436 (Ar-C-7) 1499 1530 (Ar-C-1 Ar-C-10) 1714 1727 (2timesC=O) Anal Calcd for C

32H42N4O8(61070) C 6294 H

693 N 917 Found C 6291 H 690 N 915

26 Preparation of Protected GAD 14 A solution of azo dye10 (152mg 0367mmol) and amine 4 (114mg 0441mmol12 eq) in dry THF (4mL) was stirred at room tem-perature (10min) 4-(46-Dimethoxy-135-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM) [13] (122mg0441mmol 12 eq) was added and the mixture was stirredat room temperature until azo dye 10 was completely disap-peared (20 h TLC EtOAc) The reaction mixture was con-centrated under diminished pressure and the crude residue

4 International Journal of Carbohydrate Chemistry

was partitioned between water (10mL) and Et2O (10mL)

and the aqueous phase extracted with Et2O (3 times 10mL) The

collected organic phases were dried (Na2SO4) filtered and

concentrated under diminished pressure Purification of thecrude residue (310 g) by flash chromatography over silica gel(14 hexane-EtOAc) gave pure 14 as a red foam solid (230mg95 yield calculated from 10) 119877

119891045 (EtOAc) 1H NMR

(25012MHz CD3CN) 120575 119 (t 3H J 70Hz CH

3) 126 129

137 141 [4s each 3H 2 times C(CH3)3] 238 252 [2m each 2H

(CH2)2] 312 (ddd 1H 1198696a6b 137Hz 119869

56a 81 Hz 1198696aNH 55HzH-6a) 336 (ddd 1H 119869

56b 52Hz 1198696bNH 64Hz H-6b) 354(q 2H J 70HzCH

3CH2N) 368 (t 2H J 59HzCH

2CH2N)

384 (ddd 1H H-5) 417 (dd 1H 11986934 79Hz 119869

45 19Hz H-4) 429 (dd 1H 119869

12 49Hz 11986923 25Hz H-2) 426 (t 2H J

59Hz CH2OCO) 457 (dd 1H H-3) 541 (d 1H H-1) 652

(bt 1H NH) 689 786 (AA1015840XX1015840 system 4H Ar-H-8 Ar-H-9 Ar-H-11 Ar-H-12) 791 831 (AA1015840XX1015840 system 4H Ar-H-2 Ar-H-3 Ar-H-5 Ar-H-6) 13C NMR (629MHz CD

3CN)

120575 124 (CH3) 245 252 262 263 [2 times C(CH

3)3] 300 309

[(CH2)2] 406 (C-6) 463 (CH

3CH2N) 494 (CH

2CH2N)

623 (CH2OCO) 669 (C-5) 714 (C-2) 715 (C-3) 722 (C-

4) 961 (C-1) 1093 1098 [2 times C(CH3)3] 1126 1233 1257

1269 (8 timesAr-CH) 1443 (Ar-C-7) 1484 (Ar-C-4) 1527 1577(Ar-C-1 Ar-C-10) 1724 1736 (2 times C=O) Anal Calcd forC32H41N5O10(65570) C 5862 H 630 N 1068 Found C

5860 H 628 N 1065

27 Preparation of Protected GAD 15 The condensationof azo dye 10 (151mg 0367mmol) and amine 5 (224mg0441mmol 12 eq) with 4-(46-dimethoxy-135-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM) [13](122mg 0441mmol 12 eq) in dry THF (4mL) wasperformed according to the procedure described above forthe preparation of 14 The flash chromatography over silicagel (19 hexane-EtOAc) of the crude reaction product led topure 15 (252mg 76 yield calculated from 10) as a red foam119877119891032 (EtOAc) 1H NMR (25012MHz CD

3CN) 120575 118 (t

3H J 70Hz CH3) 127 133 [2s each 6H 2 times C(CH

3)3]

137 142 [2s each 3H C(CH3)3] 244 255 [2m each 2H

(CH2)2] 343 346 (2s each 3H 2 times OCH

3) 311 (ddd 1H

11986951015840 61015840a 88Hz 11986961015840aNH 52Hz 11986961015840a61015840b 134Hz H-61015840a) 332 (dd1H 1198691101584021015840 80Hz 119869

2101584031015840 73Hz H-21015840) 351 (q 2H J 70Hz

CH3CH2N) 367 (m 2H J 60Hz CH

2CH2N) 370ndash375

(m 3H H-51015840 H-61015840b OH-21015840) 382 (dd 1H 11986945 52Hz 119869

3413Hz H-4) 394 (dd 1H 119869

3101584041015840 34Hz H-31015840) 400 (dd 1H

1198696a6b 81 Hz 11986956a 63Hz H-6a) 403 (dd 1H 119869

23 72Hz H-3)404ndash410 (m 2H H-41015840 H-6b) 422 (dt 1H 119869

56a = 11986956b63Hz H-5) 427 (t 2H J 60Hz CH

2OCO) 431 (d 1H H-

11015840) 435 (d 1H 11986912 64Hz H-1) 441 (dd 1H H-2) 668 (bt

1H NH) 685 768 (AA1015840XX1015840 system 4H Ar-H-8 Ar-H-9Ar-H-11 Ar-H-12) 788 829 (AA1015840XX1015840 system 4H Ar-H-2Ar-H-3 Ar-H-5 Ar-H-6) 13C NMR (629MHz CD

3CN)

120575 124 (CH3) 251 264 265 269 274 284 [3 times C(CH

3)3]

309 299 [(CH2)2] 409 (C-61015840) 462 (CH

3CH2N) 495

(OCH2CH2N) 560 580 (2 timesOCH

3) 623 (CH

2OCO) 660

(C-6) 746 (C-21015840) 726 (C-51015840) 750 (C-41015840) 774 (C-2) 776(C-5) 777 (C-4) 784 (C-3) 800 (C-31015840) 1041 (C-11015840) 1082

(C-1) 1092 1104 1106 [3 times C(CH3)3] 1126 1233 1257

1269 (8 times Ar-CH) 1442 (Ar-C-7) 1483 (Ar-C-4) 15271576 (Ar-C-1 Ar-C-10) 1723 1737 (2 times C=O) Anal Calcdfor C43H61N5O16

(90337) C 5713 H 680 N 775 FoundC 5711 H 677 N 772

28 Preparation of Deprotected GAD 16 A solution of 11(107 g 155mmol) in 90 aqueous CF

3COOH (70mL) was

stirred at room temperature until the starting material wascompletely disappeared (3 h TLC EtOAc) The red-violetsolution was concentrated under diminished pressure andrepeatedly coevaporated with toluene (5 times 30mL)The cruderesiduewas dissolved inEtOAc (100mL) andneutralizedwithsaturated aqueous NaHCO

3(20mL)The aqueous phase was

extracted with EtOAc (3 times 50mL) and the collected layerswere dried filtered and concentrated under diminishedpressure The residue was triturated with Et

2O and the red

residue was constituted (NMR) only by the azo dye 16(640mg 98 yield) as a mixture of 120572- and 120573-pyranoseanomers (NMR) in a ratio of 3 2 calculated on the basis ofthe relative C-1 signal intensities Compound 16 was a redsolid foam 119877

119891021 (91 EtOAc-MeOH) Selected 1H NMR

(20013MHz CD3OD) signals for both anomers 120575 106 (t

3H J 67Hz CH3) 248ndash230 [m 4H (CH

2)2] 673 764

(AA1015840XX1015840 system 4H Ar-H-8 Ar-H-9 Ar-H-11 Ar-H-12)754 (bd 1H Ar-H-6) 800 (dd 1H 119869

56 90Hz Ar-H-5) 840(d 1H 119869

35 22Hz Ar-H-3) 13CNMR (503MHz CD3OD) 120575

120572-pyranose 408 (C-6) 688 (C-5) 692 (C-4) 697 (C-2 C-3)938 (C-1) 120573-pyranose 407 (C-6) 691 (C-4) 725 (C-3) 730737 (C-2 C-5) 978 (C-1) cluster of signals for both anomers120575 125 (CH

3) 294ndash309 [(CH

2)2] 459 (CH

3CH2N) 489

(OCH2CH2N) 620 (CH

2OCO) 1122ndash1272 (Ar-CH) 1330

(Ar-C-2) 1439 (Ar-C-7) 1470 (Ar-C-4) 1526 1528 (Ar-C-1Ar-C-10) 1724 1732 (2 times C=O) Calcd for C

26H32ClN5O10

(61001) C 5119 H 529 N 1148 Found C 5117 H 528 N1145

29 Preparation of Deprotected GAD 17 Hydrolysis of 12(640mg 0682mmol) with 90 aqueous CF

3COOH (8mL)

was performed as described above for the preparation of 16After 2 h of stirring the red-violet solution was concentratedunder diminished pressure neutralized and extracted asdescribed above to give a red foam constituted (NMR) onlyby the azo dye 17 (485mg 92 yield) as a mixture of 120572- and120573-pyranose anomers (NMR) in the ratio of 3 2 calculated onthe basis of the relative C-1 signal intensities Compound 17was a red solid foam 119877

119891018 (82 EtOAc-MeOH) 120582max

49325 nm (MeOH) Selected 1H NMR (20013MHzCD3OD) 120575 120 (t 3H J 71 Hz CH

3 120572- and 120573-pyranose)

248 257 [2m each 2H (CH2)2 120572- and 120573-pyranose] 318

(dd 1H 11986912 78Hz 119869

23 90Hz H-2 120573-pyranose) 418 (d1H 1198691101584021015840 80Hz H-11015840 120572-pyranose) 420 (d 1H 119869

1101584021015840 78Hz

H-11015840 120573-pyranose) 425 (bt 2H J 64Hz CH2OCO 120572-

and 120573-pyranose) 431 (bt 2H J 66Hz CH2OCO 120572- and

120573-pyranose) 448 (d 1H H-1 120573-pyranose) 449ndash461 (mH-21015840 120572- and 120573-pyranose) 506 (d 1H 119869

12 37Hz H-1 120572-pyranose) 685 783 (AA1015840XX1015840 system 4H Ar-H-8 Ar-H-9

International Journal of Carbohydrate Chemistry 5

O

X

O

O

YZ

SuccinylationO

X

O

O

YZ

HN

O

O

OH

Me2C

NH2

(4) X = HZ = Y = O2CMe2(5) X = OGlcY = H Z = OH

(6) X = HZ = Y = O2CMe2(7) X = OGlcY = H Z = OH

Me2C

3 56-di-O-isopropylidene-aldehydo-D-glucose dimethyl acetalGlc = 2

Scheme 1 Protected aminosugars (4 and 5) and their monosuccinylamides (6 and 7)

Ar-H-11 Ar-H-12 120572- and 120573-pyranose) 772 (bd 1H Ar-H-6120572- and 120573-pyranose) 813 (bd 1H J 91Hz Ar-H-5 120572- and120573-pyranose) 832 (bd 1H Ar-H-3 120572- and 120573-pyranose) 13CNMR (629MHz CD

3OD) 120575 120572-pyranose 413 (C-61015840) 620

(C-6) 705 (C-41015840) 714 (C-5) 721 (C-21015840) 724 (C-2) 730(C-3) 734 (C-31015840) 760 (C-51015840) 811 (C-4) 937 (C-11015840) 1050(C-1) 120573-pyranose 412 (C-61015840) 628 (C-6) 704 (C-41015840) 723(C-21015840) 731 (C-31015840) 745 746 (C-3 C-2) 747 (C-5) 762(C-51015840) 805 (C-4) 981 (C-11015840) 1053 (C-1) cluster of signalsfor both anomers 120575 125 (CH

3) 303 313 [(CH

2)2] 467

(CH3CH2N) 500 (OCH

2CH2N) 629 (CH

2OCO) 1129ndash

1299 (7 times Ar-CH) 1347 (Ar-C-2) 1456 (Ar-C-7) 1486(Ar-C-4) 1536 1543 (Ar-C-1 Ar-C-10) 1744 1749 (2 timesC=O) Anal Calcd for C

32H42ClN5O15(77215) C 4978 H

548 N 907 Found C 4975 H 546 N 905

210 Preparation of Deprotected GAD 18 Thehydrolysis of 13(193mg 0316mmol) with 90 aqueous CF

3COOH (3mL)

was performed as described above for the preparation of 16After 2 h of stirring the red-violet solution was concentratedunder diminished pressure neutralized (saturated aqueousNaHCO

3) until the red-violet colour turned to yellow-

orange and extracted as described above to give a yellowfoam constituted (NMR) only by the azo dye 18 (160mg 95yield) Compound 18 was a mixture of 120572- and 120573-pyranoseanomers (NMR) in the ratio of 1 1 calculated on the basis ofthe relative C-1 signal intensities119877

119891019 (91 EtOAc-MeOH)

120582max 41125 nm (MeOH) Selected 1H NMR (20013MHzCD3OD) signals for both anomers 120575 121 (t 3H J 61 Hz

CH3) 258 [m 4H (CH

2)2] 683 (m 2H Ar-H-9 Ar-H-11)

735ndash750 (m 3H Ar-H-3 Ar-H-4 Ar-H-5) 775ndash783 (m 4HAr-H-2 Ar-H-6 Ar-H-8 Ar-H-12) 13C NMR (629MHzCD3OD) 120575 120572-pyranose 401 (C-6) 675 (C-5) 694 695

697 (C-2 C-3 C-4) 936 (C-1) 120573-pyranose 405 (C-6) 703(C-4) 721 (C-3) 731 741 (C-2 C-5) 982 (C-1) cluster ofsignals for both anomers 120575 119 (CH

3) 285 286 [(CH

2)2]

462 (CH3CH2N) 529 (OCH

2CH2N) 598 (CH

2OCO) 1111

1225 1257 1295 1299 (Ar-CH) 1432 (Ar-C-7) 1501 1530(Ar-C-1 Ar-C-10) 1740 1742 (2 times C=O) Anal Calcd for

C26H34N4O8(53057) C 5886 H 646 N 1056 Found C

5883 H 642 N 1053

3 Results and Discussion

In the search of new derivatives to be tested as new GADswe followed the same strategy used for the synthesis of thedi-estereal [4 5] (1) and diethereal [6] (2) compoundsWe were interested in preparing structures with differentfunctional groups at the attachment point with the linkerin order to evaluate the synthetic accessibility and at alater stage the effect of these changes both on the stabilityduring the dyeing process and on the tinctorial properties Toconstruct the amido-estereal mixed GADs we used appro-priately protected 6-amino-galactose derivatives in either thecondensation reaction with monosuccinyl-azo dye or aftertheir conversion into monosuccinyl derivatives This wouldallow us to study the two complementary strategies and toidentify the best pathway

Treatment of 4 [10] and 5 [8] with succinic anhydridein methanol (Scheme 1) afforded in good yields the cor-responding monosuccinyl derivatives 6 (76 yield) and 7(98 yield) that were utilized in the GAD synthesis via routeA (Scheme 2) Azo dyes 8ndash10 (Figure 2) were employed ascounterpart in the condensation reaction

In particular the known yellow azo dye (8) [12] and thecommercial Disperse Red 13 (9) were used in the preparationof GADs following route A (Scheme 2) while derivative10 prepared by succinylation of commercial alcoholic azodye Disperse Red 1 [4] was employed in the condensationreaction with the aminosugar derivatives 4 [10] and 5 [8](route B)

The coupling reactions were performed in THF withNN1015840-dicyclohexylcarbodiimide (DCC method a) or 4-(46-dimethoxy-135-triazin-2-yl)-4-methylmorpholinium chlo-ride (DMTMM method b) prepared according to Kun-ishima et al [13] from 2-chloro-46-dimethoxy-135-triazine(CDMT) andN-methylmorpholine (NMM) at room temper-ature The results obtained in the preparation of protectedGADs 11ndash15 are summarised in Table 1 The two possible

6 International Journal of Carbohydrate Chemistry

NRNR

NN

OR

OO

O OGlc

OO

OO O

OO

OOH

OGlc

OO

OO O

Route B

Route AR998400

OR998400998400

+6 or 7

R998400

OR998400998400

(9) R = NO2R998400= ClR998400998400

= H8( ) R = R998400

= R998400998400= H (11) R = NO2R

998400= ClR998400998400

= A(12) R = NO2R

998400= ClR998400998400

= B(13) R = R998400

= HR998400998400= A

OCO(CH2)2CONH-R

(10) R = CO(CH2)2COOH (14) R = C(15) R = D

O2NO2N

A = Me2CNHCO(CH2)2CO

B = Me2C

C = Me2C

D = Me2C

OH

NHCO(CH2)2CO

N=N

N=N N=N+4 or 5

N=N

Me2C Me2C

Scheme 2 Protected amido-ester GADs prepared through either method A or method B

NR

(9) R = NO2R998400= ClR998400998400

= H(10) R = NO2R

998400= HR998400998400

= CO(CH2)2COOH

8( ) R = R998400= R998400998400

= H

R998400

OR998400998400

N=N

Figure 2 Monoazo dyes 8-9 and monosuccinyl-azo dye 10

approaches gave comparable results and the desired productswere isolated in good to excellent yields

It is noteworthy that the succinyl derivatives 7 and 10could be used as crudes without affecting the outcome of thecondensation reaction In the case of protected compounds11ndash13 the final deprotected GADs 16ndash18 (Figure 3) wereobtained by simply removing the acetal protecting groups bymeans of acid hydrolysis as we previously reported [4ndash6] fortype 1 and type 2 derivatives (90 aqueous CF

3COOH room

temperature)Deprotected GADs were obtained in good yields (92ndash

98) as red (16-17) or yellow-orange (18) amorphousresidues constituted by mixtures of anomers (NMR analysis)

Isomeric forms of the 16ndash18 were identified by comparisonof their NMR data with those reported for analogous com-pounds (types 1-2) [4ndash6] The UV-Vis absorption spectra fora deprotected red GAD (17) and for the deprotected yellowGAD (18) were recorded in MeOH As for the previous twogenerations of GADs [4 5] the glycoconjugation process didnot affect the absorption properties of the dyes and 17 and18 were characterised by almost the same 120582max values of theparent not conjugated dyes (120582max around 495 nm for the redcompounds 9 12 and 17 and around 410 nm for the yellow-orange compounds 8 13 and 18)

4 Conclusions

In conclusions we presented the access to the third gen-eration of GADs exploring two complementary routes Theobtained compounds are characterized by different attach-ment points between the chromophore or the sugar and thelinker The presence of the amido bond could permit a novelsynthetic pathway to GADs for example by using enzymes[14] for the condensation reaction Detailed analysis of thestability and tinctorial properties of the third generation ofGADs are currently under investigation the results of whichwill be published in due course

International Journal of Carbohydrate Chemistry 7

Table 1 Preparation of amido-ester protected GADs

Entry Reactants Condensation system Condensation product (yield)Sugar moiety Dye moiety

1 6 9 Method A 11 (74)2 7 9 Method A 12 (82)3 6 8 Method A 13 (86)4 4 10 Method B 14 (95)5 5 10 Method B 15 (76)Method A DCC DMAP and THF method B DMTMM and THF

O

O

OO

HO

OH

NR

R998400

OR998400998400

Gal =

Lac =

NHCO(CH2)2CO-

(16) R = NO2R998400= ClR998400998400

= Gal(17) R = NO2R

998400= ClR998400998400

= Lac(18) R = R998400

= HR998400998400= Gal

NHCO(CH2)2CO-

OH

OHOH

HO

OH

HOOH

OH

OH

N=N

Figure 3 Conjugated deprotected GADs 16ndash18

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

References

[1] H-K Rouette Encyclopedia of Textile Finishing SpringerBerlin Germany 2001

[2] J H Hofenk de Graaf The Colourful Past Origins Chemistryand Identification of Natural Dyestuffs Abegg-Stitung Riggs-berg Switzerland Archetype Pubblications London UK 2004

[3] MNeamtu I SiminiceanuA Yediler andAKettrup ldquoKineticsof decolorization and mineralization of reactive azo dyes inaqueous solution by the UVH

2O2oxidationrdquo Dyes and Pig-

ments vol 53 no 2 pp 93ndash99 2002[4] G Bartalucci R Bianchini G Catelani F DrsquoAndrea and L

Guazzelli ldquoNaturalised dyes a simple straightforward syntheticroute to a new class of dyesmdashglycoazodyes (GADs)rdquo EuropeanJournal of Organic Chemistry no 4 pp 588ndash595 2007

[5] R Bianchini G Catelani R Cecconi et al ldquolsquoNaturalizationrsquo oftextile disperse dyes through glycoconjugation the case of abis(2-hydroxyethyl) group containing azo dyerdquo CarbohydrateResearch vol 343 no 12 pp 2067ndash2074 2008

[6] R Bianchini G Catelani R Cecconi et al ldquoEthereal glyco-conjugated azodyes (GADs) a new group of water-solublenaturalised dyesrdquo European Journal of Organic Chemistry no3 pp 444ndash454 2008

[7] A Porri R Baroncelli L Guglielminetti et al ldquoFusariumoxysporum degradation and detoxification of a new textile-glycoconjugate azo dye (GAD)rdquo Fungal Biology vol 115 no 1pp 30ndash37 2011

[8] J Isaad M Rolla and R Bianchini ldquoSynthesis of water-solublelarge naturalised dyes through double glycoconjugationrdquo Euro-pean Journal of Organic Chemistry no 17 pp 2748ndash2764 2009

[9] R Bianchini M Rolla J Isaad et al ldquoEfficient double glyco-conjugation to naturalize high molecular weight disperse dyesrdquoCarbohydrate Research vol 356 pp 104ndash109 2012

[10] D D Perrin W L F D Armarego and R Perrin Purificationof Laboratory Chemicals Pergamon Press Oxford UK 2ndedition 1980

[11] J Yang X Fu Q Jia et al ldquoStudies on the substrate specificity ofEscherichia coli galactokinaserdquoOrganic Letters vol 5 no 13 pp2223ndash2226 2003

[12] HWahl Y Arnould andM Simon ldquoDyes for cellulose acetateII Poly(hydroxyethyl)aniline dyesrdquo Bulletin de la Societe Chim-ique de France pp 366ndash369 1952

[13] M Kunishima C Kawachi F Iwasaki K Terao and STani ldquoSynthesis and characterization of 4-(46-dimethoxy-135-triazin-2-yl)- 4-methylmorpholinium chloriderdquo Tetrahe-dron Letters vol 40 no 29 pp 5327ndash5330 1999

[14] J Sharma D Batovska Y Kuwamori and Y Asano ldquoEnzymaticchemoselective synthesis of secondary-amide surfactant fromN-methylethanol aminerdquo Journal of Bioscience and Bioengineer-ing vol 100 no 6 pp 662ndash666 2005

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

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Carbohydrate Chemistry

International Journal of

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Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

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Analytical Methods in Chemistry

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Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Medicinal ChemistryInternational Journal of

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Chromatography Research International

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Quantum Chemistry

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CatalystsJournal of

4 International Journal of Carbohydrate Chemistry

was partitioned between water (10mL) and Et2O (10mL)

and the aqueous phase extracted with Et2O (3 times 10mL) The

collected organic phases were dried (Na2SO4) filtered and

concentrated under diminished pressure Purification of thecrude residue (310 g) by flash chromatography over silica gel(14 hexane-EtOAc) gave pure 14 as a red foam solid (230mg95 yield calculated from 10) 119877

119891045 (EtOAc) 1H NMR

(25012MHz CD3CN) 120575 119 (t 3H J 70Hz CH

3) 126 129

137 141 [4s each 3H 2 times C(CH3)3] 238 252 [2m each 2H

(CH2)2] 312 (ddd 1H 1198696a6b 137Hz 119869

56a 81 Hz 1198696aNH 55HzH-6a) 336 (ddd 1H 119869

56b 52Hz 1198696bNH 64Hz H-6b) 354(q 2H J 70HzCH

3CH2N) 368 (t 2H J 59HzCH

2CH2N)

384 (ddd 1H H-5) 417 (dd 1H 11986934 79Hz 119869

45 19Hz H-4) 429 (dd 1H 119869

12 49Hz 11986923 25Hz H-2) 426 (t 2H J

59Hz CH2OCO) 457 (dd 1H H-3) 541 (d 1H H-1) 652

(bt 1H NH) 689 786 (AA1015840XX1015840 system 4H Ar-H-8 Ar-H-9 Ar-H-11 Ar-H-12) 791 831 (AA1015840XX1015840 system 4H Ar-H-2 Ar-H-3 Ar-H-5 Ar-H-6) 13C NMR (629MHz CD

3CN)

120575 124 (CH3) 245 252 262 263 [2 times C(CH

3)3] 300 309

[(CH2)2] 406 (C-6) 463 (CH

3CH2N) 494 (CH

2CH2N)

623 (CH2OCO) 669 (C-5) 714 (C-2) 715 (C-3) 722 (C-

4) 961 (C-1) 1093 1098 [2 times C(CH3)3] 1126 1233 1257

1269 (8 timesAr-CH) 1443 (Ar-C-7) 1484 (Ar-C-4) 1527 1577(Ar-C-1 Ar-C-10) 1724 1736 (2 times C=O) Anal Calcd forC32H41N5O10(65570) C 5862 H 630 N 1068 Found C

5860 H 628 N 1065

27 Preparation of Protected GAD 15 The condensationof azo dye 10 (151mg 0367mmol) and amine 5 (224mg0441mmol 12 eq) with 4-(46-dimethoxy-135-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM) [13](122mg 0441mmol 12 eq) in dry THF (4mL) wasperformed according to the procedure described above forthe preparation of 14 The flash chromatography over silicagel (19 hexane-EtOAc) of the crude reaction product led topure 15 (252mg 76 yield calculated from 10) as a red foam119877119891032 (EtOAc) 1H NMR (25012MHz CD

3CN) 120575 118 (t

3H J 70Hz CH3) 127 133 [2s each 6H 2 times C(CH

3)3]

137 142 [2s each 3H C(CH3)3] 244 255 [2m each 2H

(CH2)2] 343 346 (2s each 3H 2 times OCH

3) 311 (ddd 1H

11986951015840 61015840a 88Hz 11986961015840aNH 52Hz 11986961015840a61015840b 134Hz H-61015840a) 332 (dd1H 1198691101584021015840 80Hz 119869

2101584031015840 73Hz H-21015840) 351 (q 2H J 70Hz

CH3CH2N) 367 (m 2H J 60Hz CH

2CH2N) 370ndash375

(m 3H H-51015840 H-61015840b OH-21015840) 382 (dd 1H 11986945 52Hz 119869

3413Hz H-4) 394 (dd 1H 119869

3101584041015840 34Hz H-31015840) 400 (dd 1H

1198696a6b 81 Hz 11986956a 63Hz H-6a) 403 (dd 1H 119869

23 72Hz H-3)404ndash410 (m 2H H-41015840 H-6b) 422 (dt 1H 119869

56a = 11986956b63Hz H-5) 427 (t 2H J 60Hz CH

2OCO) 431 (d 1H H-

11015840) 435 (d 1H 11986912 64Hz H-1) 441 (dd 1H H-2) 668 (bt

1H NH) 685 768 (AA1015840XX1015840 system 4H Ar-H-8 Ar-H-9Ar-H-11 Ar-H-12) 788 829 (AA1015840XX1015840 system 4H Ar-H-2Ar-H-3 Ar-H-5 Ar-H-6) 13C NMR (629MHz CD

3CN)

120575 124 (CH3) 251 264 265 269 274 284 [3 times C(CH

3)3]

309 299 [(CH2)2] 409 (C-61015840) 462 (CH

3CH2N) 495

(OCH2CH2N) 560 580 (2 timesOCH

3) 623 (CH

2OCO) 660

(C-6) 746 (C-21015840) 726 (C-51015840) 750 (C-41015840) 774 (C-2) 776(C-5) 777 (C-4) 784 (C-3) 800 (C-31015840) 1041 (C-11015840) 1082

(C-1) 1092 1104 1106 [3 times C(CH3)3] 1126 1233 1257

1269 (8 times Ar-CH) 1442 (Ar-C-7) 1483 (Ar-C-4) 15271576 (Ar-C-1 Ar-C-10) 1723 1737 (2 times C=O) Anal Calcdfor C43H61N5O16

(90337) C 5713 H 680 N 775 FoundC 5711 H 677 N 772

28 Preparation of Deprotected GAD 16 A solution of 11(107 g 155mmol) in 90 aqueous CF

3COOH (70mL) was

stirred at room temperature until the starting material wascompletely disappeared (3 h TLC EtOAc) The red-violetsolution was concentrated under diminished pressure andrepeatedly coevaporated with toluene (5 times 30mL)The cruderesiduewas dissolved inEtOAc (100mL) andneutralizedwithsaturated aqueous NaHCO

3(20mL)The aqueous phase was

extracted with EtOAc (3 times 50mL) and the collected layerswere dried filtered and concentrated under diminishedpressure The residue was triturated with Et

2O and the red

residue was constituted (NMR) only by the azo dye 16(640mg 98 yield) as a mixture of 120572- and 120573-pyranoseanomers (NMR) in a ratio of 3 2 calculated on the basis ofthe relative C-1 signal intensities Compound 16 was a redsolid foam 119877

119891021 (91 EtOAc-MeOH) Selected 1H NMR

(20013MHz CD3OD) signals for both anomers 120575 106 (t

3H J 67Hz CH3) 248ndash230 [m 4H (CH

2)2] 673 764

(AA1015840XX1015840 system 4H Ar-H-8 Ar-H-9 Ar-H-11 Ar-H-12)754 (bd 1H Ar-H-6) 800 (dd 1H 119869

56 90Hz Ar-H-5) 840(d 1H 119869

35 22Hz Ar-H-3) 13CNMR (503MHz CD3OD) 120575

120572-pyranose 408 (C-6) 688 (C-5) 692 (C-4) 697 (C-2 C-3)938 (C-1) 120573-pyranose 407 (C-6) 691 (C-4) 725 (C-3) 730737 (C-2 C-5) 978 (C-1) cluster of signals for both anomers120575 125 (CH

3) 294ndash309 [(CH

2)2] 459 (CH

3CH2N) 489

(OCH2CH2N) 620 (CH

2OCO) 1122ndash1272 (Ar-CH) 1330

(Ar-C-2) 1439 (Ar-C-7) 1470 (Ar-C-4) 1526 1528 (Ar-C-1Ar-C-10) 1724 1732 (2 times C=O) Calcd for C

26H32ClN5O10

(61001) C 5119 H 529 N 1148 Found C 5117 H 528 N1145

29 Preparation of Deprotected GAD 17 Hydrolysis of 12(640mg 0682mmol) with 90 aqueous CF

3COOH (8mL)

was performed as described above for the preparation of 16After 2 h of stirring the red-violet solution was concentratedunder diminished pressure neutralized and extracted asdescribed above to give a red foam constituted (NMR) onlyby the azo dye 17 (485mg 92 yield) as a mixture of 120572- and120573-pyranose anomers (NMR) in the ratio of 3 2 calculated onthe basis of the relative C-1 signal intensities Compound 17was a red solid foam 119877

119891018 (82 EtOAc-MeOH) 120582max

49325 nm (MeOH) Selected 1H NMR (20013MHzCD3OD) 120575 120 (t 3H J 71 Hz CH

3 120572- and 120573-pyranose)

248 257 [2m each 2H (CH2)2 120572- and 120573-pyranose] 318

(dd 1H 11986912 78Hz 119869

23 90Hz H-2 120573-pyranose) 418 (d1H 1198691101584021015840 80Hz H-11015840 120572-pyranose) 420 (d 1H 119869

1101584021015840 78Hz

H-11015840 120573-pyranose) 425 (bt 2H J 64Hz CH2OCO 120572-

and 120573-pyranose) 431 (bt 2H J 66Hz CH2OCO 120572- and

120573-pyranose) 448 (d 1H H-1 120573-pyranose) 449ndash461 (mH-21015840 120572- and 120573-pyranose) 506 (d 1H 119869

12 37Hz H-1 120572-pyranose) 685 783 (AA1015840XX1015840 system 4H Ar-H-8 Ar-H-9

International Journal of Carbohydrate Chemistry 5

O

X

O

O

YZ

SuccinylationO

X

O

O

YZ

HN

O

O

OH

Me2C

NH2

(4) X = HZ = Y = O2CMe2(5) X = OGlcY = H Z = OH

(6) X = HZ = Y = O2CMe2(7) X = OGlcY = H Z = OH

Me2C

3 56-di-O-isopropylidene-aldehydo-D-glucose dimethyl acetalGlc = 2

Scheme 1 Protected aminosugars (4 and 5) and their monosuccinylamides (6 and 7)

Ar-H-11 Ar-H-12 120572- and 120573-pyranose) 772 (bd 1H Ar-H-6120572- and 120573-pyranose) 813 (bd 1H J 91Hz Ar-H-5 120572- and120573-pyranose) 832 (bd 1H Ar-H-3 120572- and 120573-pyranose) 13CNMR (629MHz CD

3OD) 120575 120572-pyranose 413 (C-61015840) 620

(C-6) 705 (C-41015840) 714 (C-5) 721 (C-21015840) 724 (C-2) 730(C-3) 734 (C-31015840) 760 (C-51015840) 811 (C-4) 937 (C-11015840) 1050(C-1) 120573-pyranose 412 (C-61015840) 628 (C-6) 704 (C-41015840) 723(C-21015840) 731 (C-31015840) 745 746 (C-3 C-2) 747 (C-5) 762(C-51015840) 805 (C-4) 981 (C-11015840) 1053 (C-1) cluster of signalsfor both anomers 120575 125 (CH

3) 303 313 [(CH

2)2] 467

(CH3CH2N) 500 (OCH

2CH2N) 629 (CH

2OCO) 1129ndash

1299 (7 times Ar-CH) 1347 (Ar-C-2) 1456 (Ar-C-7) 1486(Ar-C-4) 1536 1543 (Ar-C-1 Ar-C-10) 1744 1749 (2 timesC=O) Anal Calcd for C

32H42ClN5O15(77215) C 4978 H

548 N 907 Found C 4975 H 546 N 905

210 Preparation of Deprotected GAD 18 Thehydrolysis of 13(193mg 0316mmol) with 90 aqueous CF

3COOH (3mL)

was performed as described above for the preparation of 16After 2 h of stirring the red-violet solution was concentratedunder diminished pressure neutralized (saturated aqueousNaHCO

3) until the red-violet colour turned to yellow-

orange and extracted as described above to give a yellowfoam constituted (NMR) only by the azo dye 18 (160mg 95yield) Compound 18 was a mixture of 120572- and 120573-pyranoseanomers (NMR) in the ratio of 1 1 calculated on the basis ofthe relative C-1 signal intensities119877

119891019 (91 EtOAc-MeOH)

120582max 41125 nm (MeOH) Selected 1H NMR (20013MHzCD3OD) signals for both anomers 120575 121 (t 3H J 61 Hz

CH3) 258 [m 4H (CH

2)2] 683 (m 2H Ar-H-9 Ar-H-11)

735ndash750 (m 3H Ar-H-3 Ar-H-4 Ar-H-5) 775ndash783 (m 4HAr-H-2 Ar-H-6 Ar-H-8 Ar-H-12) 13C NMR (629MHzCD3OD) 120575 120572-pyranose 401 (C-6) 675 (C-5) 694 695

697 (C-2 C-3 C-4) 936 (C-1) 120573-pyranose 405 (C-6) 703(C-4) 721 (C-3) 731 741 (C-2 C-5) 982 (C-1) cluster ofsignals for both anomers 120575 119 (CH

3) 285 286 [(CH

2)2]

462 (CH3CH2N) 529 (OCH

2CH2N) 598 (CH

2OCO) 1111

1225 1257 1295 1299 (Ar-CH) 1432 (Ar-C-7) 1501 1530(Ar-C-1 Ar-C-10) 1740 1742 (2 times C=O) Anal Calcd for

C26H34N4O8(53057) C 5886 H 646 N 1056 Found C

5883 H 642 N 1053

3 Results and Discussion

In the search of new derivatives to be tested as new GADswe followed the same strategy used for the synthesis of thedi-estereal [4 5] (1) and diethereal [6] (2) compoundsWe were interested in preparing structures with differentfunctional groups at the attachment point with the linkerin order to evaluate the synthetic accessibility and at alater stage the effect of these changes both on the stabilityduring the dyeing process and on the tinctorial properties Toconstruct the amido-estereal mixed GADs we used appro-priately protected 6-amino-galactose derivatives in either thecondensation reaction with monosuccinyl-azo dye or aftertheir conversion into monosuccinyl derivatives This wouldallow us to study the two complementary strategies and toidentify the best pathway

Treatment of 4 [10] and 5 [8] with succinic anhydridein methanol (Scheme 1) afforded in good yields the cor-responding monosuccinyl derivatives 6 (76 yield) and 7(98 yield) that were utilized in the GAD synthesis via routeA (Scheme 2) Azo dyes 8ndash10 (Figure 2) were employed ascounterpart in the condensation reaction

In particular the known yellow azo dye (8) [12] and thecommercial Disperse Red 13 (9) were used in the preparationof GADs following route A (Scheme 2) while derivative10 prepared by succinylation of commercial alcoholic azodye Disperse Red 1 [4] was employed in the condensationreaction with the aminosugar derivatives 4 [10] and 5 [8](route B)

The coupling reactions were performed in THF withNN1015840-dicyclohexylcarbodiimide (DCC method a) or 4-(46-dimethoxy-135-triazin-2-yl)-4-methylmorpholinium chlo-ride (DMTMM method b) prepared according to Kun-ishima et al [13] from 2-chloro-46-dimethoxy-135-triazine(CDMT) andN-methylmorpholine (NMM) at room temper-ature The results obtained in the preparation of protectedGADs 11ndash15 are summarised in Table 1 The two possible

6 International Journal of Carbohydrate Chemistry

NRNR

NN

OR

OO

O OGlc

OO

OO O

OO

OOH

OGlc

OO

OO O

Route B

Route AR998400

OR998400998400

+6 or 7

R998400

OR998400998400

(9) R = NO2R998400= ClR998400998400

= H8( ) R = R998400

= R998400998400= H (11) R = NO2R

998400= ClR998400998400

= A(12) R = NO2R

998400= ClR998400998400

= B(13) R = R998400

= HR998400998400= A

OCO(CH2)2CONH-R

(10) R = CO(CH2)2COOH (14) R = C(15) R = D

O2NO2N

A = Me2CNHCO(CH2)2CO

B = Me2C

C = Me2C

D = Me2C

OH

NHCO(CH2)2CO

N=N

N=N N=N+4 or 5

N=N

Me2C Me2C

Scheme 2 Protected amido-ester GADs prepared through either method A or method B

NR

(9) R = NO2R998400= ClR998400998400

= H(10) R = NO2R

998400= HR998400998400

= CO(CH2)2COOH

8( ) R = R998400= R998400998400

= H

R998400

OR998400998400

N=N

Figure 2 Monoazo dyes 8-9 and monosuccinyl-azo dye 10

approaches gave comparable results and the desired productswere isolated in good to excellent yields

It is noteworthy that the succinyl derivatives 7 and 10could be used as crudes without affecting the outcome of thecondensation reaction In the case of protected compounds11ndash13 the final deprotected GADs 16ndash18 (Figure 3) wereobtained by simply removing the acetal protecting groups bymeans of acid hydrolysis as we previously reported [4ndash6] fortype 1 and type 2 derivatives (90 aqueous CF

3COOH room

temperature)Deprotected GADs were obtained in good yields (92ndash

98) as red (16-17) or yellow-orange (18) amorphousresidues constituted by mixtures of anomers (NMR analysis)

Isomeric forms of the 16ndash18 were identified by comparisonof their NMR data with those reported for analogous com-pounds (types 1-2) [4ndash6] The UV-Vis absorption spectra fora deprotected red GAD (17) and for the deprotected yellowGAD (18) were recorded in MeOH As for the previous twogenerations of GADs [4 5] the glycoconjugation process didnot affect the absorption properties of the dyes and 17 and18 were characterised by almost the same 120582max values of theparent not conjugated dyes (120582max around 495 nm for the redcompounds 9 12 and 17 and around 410 nm for the yellow-orange compounds 8 13 and 18)

4 Conclusions

In conclusions we presented the access to the third gen-eration of GADs exploring two complementary routes Theobtained compounds are characterized by different attach-ment points between the chromophore or the sugar and thelinker The presence of the amido bond could permit a novelsynthetic pathway to GADs for example by using enzymes[14] for the condensation reaction Detailed analysis of thestability and tinctorial properties of the third generation ofGADs are currently under investigation the results of whichwill be published in due course

International Journal of Carbohydrate Chemistry 7

Table 1 Preparation of amido-ester protected GADs

Entry Reactants Condensation system Condensation product (yield)Sugar moiety Dye moiety

1 6 9 Method A 11 (74)2 7 9 Method A 12 (82)3 6 8 Method A 13 (86)4 4 10 Method B 14 (95)5 5 10 Method B 15 (76)Method A DCC DMAP and THF method B DMTMM and THF

O

O

OO

HO

OH

NR

R998400

OR998400998400

Gal =

Lac =

NHCO(CH2)2CO-

(16) R = NO2R998400= ClR998400998400

= Gal(17) R = NO2R

998400= ClR998400998400

= Lac(18) R = R998400

= HR998400998400= Gal

NHCO(CH2)2CO-

OH

OHOH

HO

OH

HOOH

OH

OH

N=N

Figure 3 Conjugated deprotected GADs 16ndash18

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

References

[1] H-K Rouette Encyclopedia of Textile Finishing SpringerBerlin Germany 2001

[2] J H Hofenk de Graaf The Colourful Past Origins Chemistryand Identification of Natural Dyestuffs Abegg-Stitung Riggs-berg Switzerland Archetype Pubblications London UK 2004

[3] MNeamtu I SiminiceanuA Yediler andAKettrup ldquoKineticsof decolorization and mineralization of reactive azo dyes inaqueous solution by the UVH

2O2oxidationrdquo Dyes and Pig-

ments vol 53 no 2 pp 93ndash99 2002[4] G Bartalucci R Bianchini G Catelani F DrsquoAndrea and L

Guazzelli ldquoNaturalised dyes a simple straightforward syntheticroute to a new class of dyesmdashglycoazodyes (GADs)rdquo EuropeanJournal of Organic Chemistry no 4 pp 588ndash595 2007

[5] R Bianchini G Catelani R Cecconi et al ldquolsquoNaturalizationrsquo oftextile disperse dyes through glycoconjugation the case of abis(2-hydroxyethyl) group containing azo dyerdquo CarbohydrateResearch vol 343 no 12 pp 2067ndash2074 2008

[6] R Bianchini G Catelani R Cecconi et al ldquoEthereal glyco-conjugated azodyes (GADs) a new group of water-solublenaturalised dyesrdquo European Journal of Organic Chemistry no3 pp 444ndash454 2008

[7] A Porri R Baroncelli L Guglielminetti et al ldquoFusariumoxysporum degradation and detoxification of a new textile-glycoconjugate azo dye (GAD)rdquo Fungal Biology vol 115 no 1pp 30ndash37 2011

[8] J Isaad M Rolla and R Bianchini ldquoSynthesis of water-solublelarge naturalised dyes through double glycoconjugationrdquo Euro-pean Journal of Organic Chemistry no 17 pp 2748ndash2764 2009

[9] R Bianchini M Rolla J Isaad et al ldquoEfficient double glyco-conjugation to naturalize high molecular weight disperse dyesrdquoCarbohydrate Research vol 356 pp 104ndash109 2012

[10] D D Perrin W L F D Armarego and R Perrin Purificationof Laboratory Chemicals Pergamon Press Oxford UK 2ndedition 1980

[11] J Yang X Fu Q Jia et al ldquoStudies on the substrate specificity ofEscherichia coli galactokinaserdquoOrganic Letters vol 5 no 13 pp2223ndash2226 2003

[12] HWahl Y Arnould andM Simon ldquoDyes for cellulose acetateII Poly(hydroxyethyl)aniline dyesrdquo Bulletin de la Societe Chim-ique de France pp 366ndash369 1952

[13] M Kunishima C Kawachi F Iwasaki K Terao and STani ldquoSynthesis and characterization of 4-(46-dimethoxy-135-triazin-2-yl)- 4-methylmorpholinium chloriderdquo Tetrahe-dron Letters vol 40 no 29 pp 5327ndash5330 1999

[14] J Sharma D Batovska Y Kuwamori and Y Asano ldquoEnzymaticchemoselective synthesis of secondary-amide surfactant fromN-methylethanol aminerdquo Journal of Bioscience and Bioengineer-ing vol 100 no 6 pp 662ndash666 2005

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

International Journal of Carbohydrate Chemistry 5

O

X

O

O

YZ

SuccinylationO

X

O

O

YZ

HN

O

O

OH

Me2C

NH2

(4) X = HZ = Y = O2CMe2(5) X = OGlcY = H Z = OH

(6) X = HZ = Y = O2CMe2(7) X = OGlcY = H Z = OH

Me2C

3 56-di-O-isopropylidene-aldehydo-D-glucose dimethyl acetalGlc = 2

Scheme 1 Protected aminosugars (4 and 5) and their monosuccinylamides (6 and 7)

Ar-H-11 Ar-H-12 120572- and 120573-pyranose) 772 (bd 1H Ar-H-6120572- and 120573-pyranose) 813 (bd 1H J 91Hz Ar-H-5 120572- and120573-pyranose) 832 (bd 1H Ar-H-3 120572- and 120573-pyranose) 13CNMR (629MHz CD

3OD) 120575 120572-pyranose 413 (C-61015840) 620

(C-6) 705 (C-41015840) 714 (C-5) 721 (C-21015840) 724 (C-2) 730(C-3) 734 (C-31015840) 760 (C-51015840) 811 (C-4) 937 (C-11015840) 1050(C-1) 120573-pyranose 412 (C-61015840) 628 (C-6) 704 (C-41015840) 723(C-21015840) 731 (C-31015840) 745 746 (C-3 C-2) 747 (C-5) 762(C-51015840) 805 (C-4) 981 (C-11015840) 1053 (C-1) cluster of signalsfor both anomers 120575 125 (CH

3) 303 313 [(CH

2)2] 467

(CH3CH2N) 500 (OCH

2CH2N) 629 (CH

2OCO) 1129ndash

1299 (7 times Ar-CH) 1347 (Ar-C-2) 1456 (Ar-C-7) 1486(Ar-C-4) 1536 1543 (Ar-C-1 Ar-C-10) 1744 1749 (2 timesC=O) Anal Calcd for C

32H42ClN5O15(77215) C 4978 H

548 N 907 Found C 4975 H 546 N 905

210 Preparation of Deprotected GAD 18 Thehydrolysis of 13(193mg 0316mmol) with 90 aqueous CF

3COOH (3mL)

was performed as described above for the preparation of 16After 2 h of stirring the red-violet solution was concentratedunder diminished pressure neutralized (saturated aqueousNaHCO

3) until the red-violet colour turned to yellow-

orange and extracted as described above to give a yellowfoam constituted (NMR) only by the azo dye 18 (160mg 95yield) Compound 18 was a mixture of 120572- and 120573-pyranoseanomers (NMR) in the ratio of 1 1 calculated on the basis ofthe relative C-1 signal intensities119877

119891019 (91 EtOAc-MeOH)

120582max 41125 nm (MeOH) Selected 1H NMR (20013MHzCD3OD) signals for both anomers 120575 121 (t 3H J 61 Hz

CH3) 258 [m 4H (CH

2)2] 683 (m 2H Ar-H-9 Ar-H-11)

735ndash750 (m 3H Ar-H-3 Ar-H-4 Ar-H-5) 775ndash783 (m 4HAr-H-2 Ar-H-6 Ar-H-8 Ar-H-12) 13C NMR (629MHzCD3OD) 120575 120572-pyranose 401 (C-6) 675 (C-5) 694 695

697 (C-2 C-3 C-4) 936 (C-1) 120573-pyranose 405 (C-6) 703(C-4) 721 (C-3) 731 741 (C-2 C-5) 982 (C-1) cluster ofsignals for both anomers 120575 119 (CH

3) 285 286 [(CH

2)2]

462 (CH3CH2N) 529 (OCH

2CH2N) 598 (CH

2OCO) 1111

1225 1257 1295 1299 (Ar-CH) 1432 (Ar-C-7) 1501 1530(Ar-C-1 Ar-C-10) 1740 1742 (2 times C=O) Anal Calcd for

C26H34N4O8(53057) C 5886 H 646 N 1056 Found C

5883 H 642 N 1053

3 Results and Discussion

In the search of new derivatives to be tested as new GADswe followed the same strategy used for the synthesis of thedi-estereal [4 5] (1) and diethereal [6] (2) compoundsWe were interested in preparing structures with differentfunctional groups at the attachment point with the linkerin order to evaluate the synthetic accessibility and at alater stage the effect of these changes both on the stabilityduring the dyeing process and on the tinctorial properties Toconstruct the amido-estereal mixed GADs we used appro-priately protected 6-amino-galactose derivatives in either thecondensation reaction with monosuccinyl-azo dye or aftertheir conversion into monosuccinyl derivatives This wouldallow us to study the two complementary strategies and toidentify the best pathway

Treatment of 4 [10] and 5 [8] with succinic anhydridein methanol (Scheme 1) afforded in good yields the cor-responding monosuccinyl derivatives 6 (76 yield) and 7(98 yield) that were utilized in the GAD synthesis via routeA (Scheme 2) Azo dyes 8ndash10 (Figure 2) were employed ascounterpart in the condensation reaction

In particular the known yellow azo dye (8) [12] and thecommercial Disperse Red 13 (9) were used in the preparationof GADs following route A (Scheme 2) while derivative10 prepared by succinylation of commercial alcoholic azodye Disperse Red 1 [4] was employed in the condensationreaction with the aminosugar derivatives 4 [10] and 5 [8](route B)

The coupling reactions were performed in THF withNN1015840-dicyclohexylcarbodiimide (DCC method a) or 4-(46-dimethoxy-135-triazin-2-yl)-4-methylmorpholinium chlo-ride (DMTMM method b) prepared according to Kun-ishima et al [13] from 2-chloro-46-dimethoxy-135-triazine(CDMT) andN-methylmorpholine (NMM) at room temper-ature The results obtained in the preparation of protectedGADs 11ndash15 are summarised in Table 1 The two possible

6 International Journal of Carbohydrate Chemistry

NRNR

NN

OR

OO

O OGlc

OO

OO O

OO

OOH

OGlc

OO

OO O

Route B

Route AR998400

OR998400998400

+6 or 7

R998400

OR998400998400

(9) R = NO2R998400= ClR998400998400

= H8( ) R = R998400

= R998400998400= H (11) R = NO2R

998400= ClR998400998400

= A(12) R = NO2R

998400= ClR998400998400

= B(13) R = R998400

= HR998400998400= A

OCO(CH2)2CONH-R

(10) R = CO(CH2)2COOH (14) R = C(15) R = D

O2NO2N

A = Me2CNHCO(CH2)2CO

B = Me2C

C = Me2C

D = Me2C

OH

NHCO(CH2)2CO

N=N

N=N N=N+4 or 5

N=N

Me2C Me2C

Scheme 2 Protected amido-ester GADs prepared through either method A or method B

NR

(9) R = NO2R998400= ClR998400998400

= H(10) R = NO2R

998400= HR998400998400

= CO(CH2)2COOH

8( ) R = R998400= R998400998400

= H

R998400

OR998400998400

N=N

Figure 2 Monoazo dyes 8-9 and monosuccinyl-azo dye 10

approaches gave comparable results and the desired productswere isolated in good to excellent yields

It is noteworthy that the succinyl derivatives 7 and 10could be used as crudes without affecting the outcome of thecondensation reaction In the case of protected compounds11ndash13 the final deprotected GADs 16ndash18 (Figure 3) wereobtained by simply removing the acetal protecting groups bymeans of acid hydrolysis as we previously reported [4ndash6] fortype 1 and type 2 derivatives (90 aqueous CF

3COOH room

temperature)Deprotected GADs were obtained in good yields (92ndash

98) as red (16-17) or yellow-orange (18) amorphousresidues constituted by mixtures of anomers (NMR analysis)

Isomeric forms of the 16ndash18 were identified by comparisonof their NMR data with those reported for analogous com-pounds (types 1-2) [4ndash6] The UV-Vis absorption spectra fora deprotected red GAD (17) and for the deprotected yellowGAD (18) were recorded in MeOH As for the previous twogenerations of GADs [4 5] the glycoconjugation process didnot affect the absorption properties of the dyes and 17 and18 were characterised by almost the same 120582max values of theparent not conjugated dyes (120582max around 495 nm for the redcompounds 9 12 and 17 and around 410 nm for the yellow-orange compounds 8 13 and 18)

4 Conclusions

In conclusions we presented the access to the third gen-eration of GADs exploring two complementary routes Theobtained compounds are characterized by different attach-ment points between the chromophore or the sugar and thelinker The presence of the amido bond could permit a novelsynthetic pathway to GADs for example by using enzymes[14] for the condensation reaction Detailed analysis of thestability and tinctorial properties of the third generation ofGADs are currently under investigation the results of whichwill be published in due course

International Journal of Carbohydrate Chemistry 7

Table 1 Preparation of amido-ester protected GADs

Entry Reactants Condensation system Condensation product (yield)Sugar moiety Dye moiety

1 6 9 Method A 11 (74)2 7 9 Method A 12 (82)3 6 8 Method A 13 (86)4 4 10 Method B 14 (95)5 5 10 Method B 15 (76)Method A DCC DMAP and THF method B DMTMM and THF

O

O

OO

HO

OH

NR

R998400

OR998400998400

Gal =

Lac =

NHCO(CH2)2CO-

(16) R = NO2R998400= ClR998400998400

= Gal(17) R = NO2R

998400= ClR998400998400

= Lac(18) R = R998400

= HR998400998400= Gal

NHCO(CH2)2CO-

OH

OHOH

HO

OH

HOOH

OH

OH

N=N

Figure 3 Conjugated deprotected GADs 16ndash18

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

References

[1] H-K Rouette Encyclopedia of Textile Finishing SpringerBerlin Germany 2001

[2] J H Hofenk de Graaf The Colourful Past Origins Chemistryand Identification of Natural Dyestuffs Abegg-Stitung Riggs-berg Switzerland Archetype Pubblications London UK 2004

[3] MNeamtu I SiminiceanuA Yediler andAKettrup ldquoKineticsof decolorization and mineralization of reactive azo dyes inaqueous solution by the UVH

2O2oxidationrdquo Dyes and Pig-

ments vol 53 no 2 pp 93ndash99 2002[4] G Bartalucci R Bianchini G Catelani F DrsquoAndrea and L

Guazzelli ldquoNaturalised dyes a simple straightforward syntheticroute to a new class of dyesmdashglycoazodyes (GADs)rdquo EuropeanJournal of Organic Chemistry no 4 pp 588ndash595 2007

[5] R Bianchini G Catelani R Cecconi et al ldquolsquoNaturalizationrsquo oftextile disperse dyes through glycoconjugation the case of abis(2-hydroxyethyl) group containing azo dyerdquo CarbohydrateResearch vol 343 no 12 pp 2067ndash2074 2008

[6] R Bianchini G Catelani R Cecconi et al ldquoEthereal glyco-conjugated azodyes (GADs) a new group of water-solublenaturalised dyesrdquo European Journal of Organic Chemistry no3 pp 444ndash454 2008

[7] A Porri R Baroncelli L Guglielminetti et al ldquoFusariumoxysporum degradation and detoxification of a new textile-glycoconjugate azo dye (GAD)rdquo Fungal Biology vol 115 no 1pp 30ndash37 2011

[8] J Isaad M Rolla and R Bianchini ldquoSynthesis of water-solublelarge naturalised dyes through double glycoconjugationrdquo Euro-pean Journal of Organic Chemistry no 17 pp 2748ndash2764 2009

[9] R Bianchini M Rolla J Isaad et al ldquoEfficient double glyco-conjugation to naturalize high molecular weight disperse dyesrdquoCarbohydrate Research vol 356 pp 104ndash109 2012

[10] D D Perrin W L F D Armarego and R Perrin Purificationof Laboratory Chemicals Pergamon Press Oxford UK 2ndedition 1980

[11] J Yang X Fu Q Jia et al ldquoStudies on the substrate specificity ofEscherichia coli galactokinaserdquoOrganic Letters vol 5 no 13 pp2223ndash2226 2003

[12] HWahl Y Arnould andM Simon ldquoDyes for cellulose acetateII Poly(hydroxyethyl)aniline dyesrdquo Bulletin de la Societe Chim-ique de France pp 366ndash369 1952

[13] M Kunishima C Kawachi F Iwasaki K Terao and STani ldquoSynthesis and characterization of 4-(46-dimethoxy-135-triazin-2-yl)- 4-methylmorpholinium chloriderdquo Tetrahe-dron Letters vol 40 no 29 pp 5327ndash5330 1999

[14] J Sharma D Batovska Y Kuwamori and Y Asano ldquoEnzymaticchemoselective synthesis of secondary-amide surfactant fromN-methylethanol aminerdquo Journal of Bioscience and Bioengineer-ing vol 100 no 6 pp 662ndash666 2005

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

6 International Journal of Carbohydrate Chemistry

NRNR

NN

OR

OO

O OGlc

OO

OO O

OO

OOH

OGlc

OO

OO O

Route B

Route AR998400

OR998400998400

+6 or 7

R998400

OR998400998400

(9) R = NO2R998400= ClR998400998400

= H8( ) R = R998400

= R998400998400= H (11) R = NO2R

998400= ClR998400998400

= A(12) R = NO2R

998400= ClR998400998400

= B(13) R = R998400

= HR998400998400= A

OCO(CH2)2CONH-R

(10) R = CO(CH2)2COOH (14) R = C(15) R = D

O2NO2N

A = Me2CNHCO(CH2)2CO

B = Me2C

C = Me2C

D = Me2C

OH

NHCO(CH2)2CO

N=N

N=N N=N+4 or 5

N=N

Me2C Me2C

Scheme 2 Protected amido-ester GADs prepared through either method A or method B

NR

(9) R = NO2R998400= ClR998400998400

= H(10) R = NO2R

998400= HR998400998400

= CO(CH2)2COOH

8( ) R = R998400= R998400998400

= H

R998400

OR998400998400

N=N

Figure 2 Monoazo dyes 8-9 and monosuccinyl-azo dye 10

approaches gave comparable results and the desired productswere isolated in good to excellent yields

It is noteworthy that the succinyl derivatives 7 and 10could be used as crudes without affecting the outcome of thecondensation reaction In the case of protected compounds11ndash13 the final deprotected GADs 16ndash18 (Figure 3) wereobtained by simply removing the acetal protecting groups bymeans of acid hydrolysis as we previously reported [4ndash6] fortype 1 and type 2 derivatives (90 aqueous CF

3COOH room

temperature)Deprotected GADs were obtained in good yields (92ndash

98) as red (16-17) or yellow-orange (18) amorphousresidues constituted by mixtures of anomers (NMR analysis)

Isomeric forms of the 16ndash18 were identified by comparisonof their NMR data with those reported for analogous com-pounds (types 1-2) [4ndash6] The UV-Vis absorption spectra fora deprotected red GAD (17) and for the deprotected yellowGAD (18) were recorded in MeOH As for the previous twogenerations of GADs [4 5] the glycoconjugation process didnot affect the absorption properties of the dyes and 17 and18 were characterised by almost the same 120582max values of theparent not conjugated dyes (120582max around 495 nm for the redcompounds 9 12 and 17 and around 410 nm for the yellow-orange compounds 8 13 and 18)

4 Conclusions

In conclusions we presented the access to the third gen-eration of GADs exploring two complementary routes Theobtained compounds are characterized by different attach-ment points between the chromophore or the sugar and thelinker The presence of the amido bond could permit a novelsynthetic pathway to GADs for example by using enzymes[14] for the condensation reaction Detailed analysis of thestability and tinctorial properties of the third generation ofGADs are currently under investigation the results of whichwill be published in due course

International Journal of Carbohydrate Chemistry 7

Table 1 Preparation of amido-ester protected GADs

Entry Reactants Condensation system Condensation product (yield)Sugar moiety Dye moiety

1 6 9 Method A 11 (74)2 7 9 Method A 12 (82)3 6 8 Method A 13 (86)4 4 10 Method B 14 (95)5 5 10 Method B 15 (76)Method A DCC DMAP and THF method B DMTMM and THF

O

O

OO

HO

OH

NR

R998400

OR998400998400

Gal =

Lac =

NHCO(CH2)2CO-

(16) R = NO2R998400= ClR998400998400

= Gal(17) R = NO2R

998400= ClR998400998400

= Lac(18) R = R998400

= HR998400998400= Gal

NHCO(CH2)2CO-

OH

OHOH

HO

OH

HOOH

OH

OH

N=N

Figure 3 Conjugated deprotected GADs 16ndash18

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

References

[1] H-K Rouette Encyclopedia of Textile Finishing SpringerBerlin Germany 2001

[2] J H Hofenk de Graaf The Colourful Past Origins Chemistryand Identification of Natural Dyestuffs Abegg-Stitung Riggs-berg Switzerland Archetype Pubblications London UK 2004

[3] MNeamtu I SiminiceanuA Yediler andAKettrup ldquoKineticsof decolorization and mineralization of reactive azo dyes inaqueous solution by the UVH

2O2oxidationrdquo Dyes and Pig-

ments vol 53 no 2 pp 93ndash99 2002[4] G Bartalucci R Bianchini G Catelani F DrsquoAndrea and L

Guazzelli ldquoNaturalised dyes a simple straightforward syntheticroute to a new class of dyesmdashglycoazodyes (GADs)rdquo EuropeanJournal of Organic Chemistry no 4 pp 588ndash595 2007

[5] R Bianchini G Catelani R Cecconi et al ldquolsquoNaturalizationrsquo oftextile disperse dyes through glycoconjugation the case of abis(2-hydroxyethyl) group containing azo dyerdquo CarbohydrateResearch vol 343 no 12 pp 2067ndash2074 2008

[6] R Bianchini G Catelani R Cecconi et al ldquoEthereal glyco-conjugated azodyes (GADs) a new group of water-solublenaturalised dyesrdquo European Journal of Organic Chemistry no3 pp 444ndash454 2008

[7] A Porri R Baroncelli L Guglielminetti et al ldquoFusariumoxysporum degradation and detoxification of a new textile-glycoconjugate azo dye (GAD)rdquo Fungal Biology vol 115 no 1pp 30ndash37 2011

[8] J Isaad M Rolla and R Bianchini ldquoSynthesis of water-solublelarge naturalised dyes through double glycoconjugationrdquo Euro-pean Journal of Organic Chemistry no 17 pp 2748ndash2764 2009

[9] R Bianchini M Rolla J Isaad et al ldquoEfficient double glyco-conjugation to naturalize high molecular weight disperse dyesrdquoCarbohydrate Research vol 356 pp 104ndash109 2012

[10] D D Perrin W L F D Armarego and R Perrin Purificationof Laboratory Chemicals Pergamon Press Oxford UK 2ndedition 1980

[11] J Yang X Fu Q Jia et al ldquoStudies on the substrate specificity ofEscherichia coli galactokinaserdquoOrganic Letters vol 5 no 13 pp2223ndash2226 2003

[12] HWahl Y Arnould andM Simon ldquoDyes for cellulose acetateII Poly(hydroxyethyl)aniline dyesrdquo Bulletin de la Societe Chim-ique de France pp 366ndash369 1952

[13] M Kunishima C Kawachi F Iwasaki K Terao and STani ldquoSynthesis and characterization of 4-(46-dimethoxy-135-triazin-2-yl)- 4-methylmorpholinium chloriderdquo Tetrahe-dron Letters vol 40 no 29 pp 5327ndash5330 1999

[14] J Sharma D Batovska Y Kuwamori and Y Asano ldquoEnzymaticchemoselective synthesis of secondary-amide surfactant fromN-methylethanol aminerdquo Journal of Bioscience and Bioengineer-ing vol 100 no 6 pp 662ndash666 2005

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

International Journal of Carbohydrate Chemistry 7

Table 1 Preparation of amido-ester protected GADs

Entry Reactants Condensation system Condensation product (yield)Sugar moiety Dye moiety

1 6 9 Method A 11 (74)2 7 9 Method A 12 (82)3 6 8 Method A 13 (86)4 4 10 Method B 14 (95)5 5 10 Method B 15 (76)Method A DCC DMAP and THF method B DMTMM and THF

O

O

OO

HO

OH

NR

R998400

OR998400998400

Gal =

Lac =

NHCO(CH2)2CO-

(16) R = NO2R998400= ClR998400998400

= Gal(17) R = NO2R

998400= ClR998400998400

= Lac(18) R = R998400

= HR998400998400= Gal

NHCO(CH2)2CO-

OH

OHOH

HO

OH

HOOH

OH

OH

N=N

Figure 3 Conjugated deprotected GADs 16ndash18

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

References

[1] H-K Rouette Encyclopedia of Textile Finishing SpringerBerlin Germany 2001

[2] J H Hofenk de Graaf The Colourful Past Origins Chemistryand Identification of Natural Dyestuffs Abegg-Stitung Riggs-berg Switzerland Archetype Pubblications London UK 2004

[3] MNeamtu I SiminiceanuA Yediler andAKettrup ldquoKineticsof decolorization and mineralization of reactive azo dyes inaqueous solution by the UVH

2O2oxidationrdquo Dyes and Pig-

ments vol 53 no 2 pp 93ndash99 2002[4] G Bartalucci R Bianchini G Catelani F DrsquoAndrea and L

Guazzelli ldquoNaturalised dyes a simple straightforward syntheticroute to a new class of dyesmdashglycoazodyes (GADs)rdquo EuropeanJournal of Organic Chemistry no 4 pp 588ndash595 2007

[5] R Bianchini G Catelani R Cecconi et al ldquolsquoNaturalizationrsquo oftextile disperse dyes through glycoconjugation the case of abis(2-hydroxyethyl) group containing azo dyerdquo CarbohydrateResearch vol 343 no 12 pp 2067ndash2074 2008

[6] R Bianchini G Catelani R Cecconi et al ldquoEthereal glyco-conjugated azodyes (GADs) a new group of water-solublenaturalised dyesrdquo European Journal of Organic Chemistry no3 pp 444ndash454 2008

[7] A Porri R Baroncelli L Guglielminetti et al ldquoFusariumoxysporum degradation and detoxification of a new textile-glycoconjugate azo dye (GAD)rdquo Fungal Biology vol 115 no 1pp 30ndash37 2011

[8] J Isaad M Rolla and R Bianchini ldquoSynthesis of water-solublelarge naturalised dyes through double glycoconjugationrdquo Euro-pean Journal of Organic Chemistry no 17 pp 2748ndash2764 2009

[9] R Bianchini M Rolla J Isaad et al ldquoEfficient double glyco-conjugation to naturalize high molecular weight disperse dyesrdquoCarbohydrate Research vol 356 pp 104ndash109 2012

[10] D D Perrin W L F D Armarego and R Perrin Purificationof Laboratory Chemicals Pergamon Press Oxford UK 2ndedition 1980

[11] J Yang X Fu Q Jia et al ldquoStudies on the substrate specificity ofEscherichia coli galactokinaserdquoOrganic Letters vol 5 no 13 pp2223ndash2226 2003

[12] HWahl Y Arnould andM Simon ldquoDyes for cellulose acetateII Poly(hydroxyethyl)aniline dyesrdquo Bulletin de la Societe Chim-ique de France pp 366ndash369 1952

[13] M Kunishima C Kawachi F Iwasaki K Terao and STani ldquoSynthesis and characterization of 4-(46-dimethoxy-135-triazin-2-yl)- 4-methylmorpholinium chloriderdquo Tetrahe-dron Letters vol 40 no 29 pp 5327ndash5330 1999

[14] J Sharma D Batovska Y Kuwamori and Y Asano ldquoEnzymaticchemoselective synthesis of secondary-amide surfactant fromN-methylethanol aminerdquo Journal of Bioscience and Bioengineer-ing vol 100 no 6 pp 662ndash666 2005

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of