168 FHANKLAND, HEATHCOTE, AND GREEN : THE NITHATION OF

XIV.-The Nitration of Diethyl Moyhobenzoyl- and

By PERCY FARADAY FRANKLAND, HENRY LEONARD HEATHCOTE, B. Sc., and CLARENCE JAMES GREEN, B.Sc.

Mono- p-toluyl- tcc'rt rates.

Diethy2 iMononilroi7enxoyZtartrate and Diethyl Xononitro-p-toluyl- tartrate.

THESE compounds mere obtained from diethyl monobenzoyltartrate and diethyl mono-p-toluyltartrate respectively, by treating them with a mixture of nitric and sulphuric acids in the cold on the chance of thus obtaining mononitrates. I n both caws, however, the NO, group entered the benzene ring, and by hydrolysis it mas shown tha t the m-nitrobenzoyl group was present in the one, and the nitro-p-toluyl group (CH,: NO, : GO = 1 : 2 : 4) in the other.

The rotatory power of these compounds was greatly affected by the nature of the solvent in which the rotation was determined (for details, see p. 173).

The rotation of the diethyl mono-nz-nitrobenzoyltartrate is of interest in connection with tha t of the mono-m-toluyltartrate, as these two compounds enable a comparison to be instituted between the respective rotatory effects of the CH, and the NO, groups occupying the same position in the benzene ring. The comparison is, however, attended with great difficulty, owing to the variable rotation of the diethyl mono-m-nitrobenzoyltartrate in different solvents ; the diethyl mono-m-toluyltartrate was only polarimetrically examined in the fused state and in glacial acetic acid solution (see P. Frankland and McCrite, 'l'rms., 1898, 73, 332). The molecular rotation of fused diethyl mono-nb-toluyltartrate a t 20" is + 44*0°, whilst in glacial acetic acid only about + 2 5 O , so that, on the whole, the rotatory effect of the nitro-group would appear to be greater than that of the methyl group occupying the same position in the molecule. A much more detailed investigation, however, will have to be made in order to complete the comparison between these two groups.

The same comparison may also be instituted by means of the three diethyl ditoluyltartrates and the three dinitrobenzoyltartrates respec- tively, and also between the three similar pairs of dimethyl esters. The &ethyl and dimethyl nitrobenzoyltartrates have been prepared and polarimetrically examined by one of us in con junction with Dr. Harger, and the results will form the subject of a future communication. It will be suflicient here to reinark that these compounds furnish over- whelming evidence tha t the NO, group exercises a higher rotatory effect than the OH, group occupying the same position in the benzene ring.

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DIETHYL MONOBENZOTL- AND MONO-P-TOLUYL-TARTRATES. 169

Again, the relative rotatory effects of the NO, and methyl groups may be ascertained from another series of compnrisons, namely, dinitro- tartaric acid and dimethoxysuccinic acid, dimethyl dinitrotartrate and dimethyl dimethoxysuccinate, diethyl dinitrotartrate and diethyl di- methoxysuccinate. The above derivatives of dimethoxysuccinic acid have recently been prepared and most fully described by Purdie, Irvine, and Barbour (Trans., 1901, 79, 973), and on comparing their figures with those found by us for the dinitrotartrates, it is obvious tha t in all cases dimethoxysuccinic acid and its esters have much higher molecular rota- tions, of the same sign, than the corresponding derivatives of dinitro- tartaric acid. Thus, in this series, the methyl group exercises a much more powerful, although similar, rotatory effect than does the nitro- group occupying the ssme position in the molecule.

W e append Purdie and Irvine's figures for the rotation of the corresponding dimethoxy-compounds, in order t o compare these with our rotatory values given in the preceding communication for dinitrotartaric acid and i ts derivatives :

Dims t hoxy succinic A c id.

[ 1'200

+ 72-28' u

Water solution, c = 175839 8.9 104 + 74-74 4.4570 + 75.39 1. i812 + 76-63

+ 89.29 3.5595 + 91.30 1.i797 + 95.80

Acetone solution, c = 8.9091

[ 11]2° + 12S.i' + 133.0 + 134.2 + 136.4 + 158.9 + 163.5 + 170.5

DirnethyZ Binaethoxysutxin ate. Die t?hy I Dime t hox ys uccin u te.

[ u]',"". [ M]?,O". 89.7 209.9"

Solvent. Water .. c=19'9988

10.0315 5.0319

c = 20 f ~ 0 3 6 10 '01 28 5'0060

alcohol.. , p= 23.0151 12'0806 6-3598

Benzene . . ,

Methyl

VOL. LXXXIII.

[ u]20"

+ 78.71" 78.45 78.50

101'63 104-66 105'47

I1 '

78-90 76.32 81 -04

[ RI: 1:. + 162.1"

ldL.6 161.7 209.4 215.6 217'3

162.5 157-2 166-9

[ u ] y , [ bI ];on.

c = 5.3752 89.11" 208.5'

p=19'3137 102'65 240'2 10.1117 104.34 243.: 5.3130 104'93 245-P

p=19.0407 87.27 204.2 9'7365 87-41 204'5 6'0569 87-66 205-1

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170 FRANKLAND, HEATHCOTE, AND GREEN: THE NITRATION OF

Thus whilst the NO, group attached to the benzene ring has hitherto exhibited a higher rotatory effect than CH, similarly attached, the comparison of nitrotartaric acid and its esters with the dimethoxysuccinates shows tha t the -O*CK, group has a higher rotatory effect than the -O*NO, group in these compounds.

On the other hand, i t will be shown by one of us, later, that NO, attached to the benzene ring has a greater rotatory effect than -O*CH, similarly combined.

The difference in the relation between the rotatory effects of the NO, and CH, groups, according as they are directly attached to the benzene ring o r united to carbon by means of oxygen, may depend on differences in the structure of the NO, group in the nitro- compounds and nitrates respectively.

The diethyi mono-m-nitrobenzoyltartrate and the corresponding di-m-nitrobenzoyltartrate enable us again to test the regularity pointed out by McCrae and Patterson with regard to the effect of the single and double substitution of diethyltartrate, and to which reference has already been made on p. 160 in the preceding communication. Thus, it mill be seen tha t the introduction of a single m-nitrobenzoyl group produces a greater dextrorotatory change than the addition of two such groups ; in fact, diethyl di-m-nitrobenz- oyltartrate is powerfully ltevorotatory. These results are thus in conformity with the above generalisation. .

The rotation of diethyl mononitrop-toluyltartrate is again extra- ordinarily dependent on the solvent, being dextrorotatory in ethyl alcohol, ethyl acetate, and chloroform, whilst it is laxorotatory in benzene arid especially SO in pyridine solution,

E x P E R I BI E N T A L.

DietlLp? i l lono-m. . iz i trobon~o~~~~rtr~te .

I n the hope of possibly obtaining a benzoylmononitrotartrate, diethyl monobenzoyltartrate was nitrated, but the reactions of the product show that the nitro-group enters t h e benzene ring, forming instead

CO,Et*CH(OH)*CH(O*CO -C'613,*N02)*C02Et. Yiethyl monobenzoyltartrute, of lnel ting point 65.5' and rotation

[a]": + 17.65 (Y. Frankland and McCrae, Trans., 1898, 73, 310), was added in small quantities at a time and with constant stirring to a mixture of five times its weight of fuming nitric acid (sp. gr. 1-52), the temperature being kept below 5" by means of an ice jacket. The mixture was then poured slowly into water containing ice, which was kept constantly stirred so tha t the temperature did not rise above 8'. The thick, oily product which separated soon became solid (amounting

(1) (3)

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DIETHYL MONOBENZOYL- AND MONO-P-TOLUYL-TARTRATES. 171

to 85-90 per cent. of the theoretical yield) and was collected and washed with water until the washings showzd only a fcLint acid reaction. The solid wac, dried on porous plates and then dissolved in benzene; the filtered solution, when t r e l t e i with low boiling ligroin until a faint milkiness mas produced, slowly yielded a solid crystallising in long, flexible, silky needles melting a t 113',* and soluble in alcohol, benzene, pyridine, chloroform, and ethyl acetate, but almost insoluble in cold carbon disulphide and ligroin :

0.2747 gave 9.8 C.C. moist nitrogen at 18' and 750 mm. 0.1352 ,, 0.2525 CO, and 0,0605 H,O. C = 50 .94 ; H = 4.97.

Cl5HI70,N requires N == 3 - 9 4 ; C = 50.70 ; H = 4.79 per cent.

N = 4.06

The results of the polarirnetric determinations made with solutions of this ester are given on p. 173.

The substance did not reduce Fehling's solution even on heating. It was easily hydrolysed with alcoholic potash, slowly even in the cold and very rapidly on warming. After hydrolysis, the alcohol was distilled off and the residud potassium salts dissolved in water. On adding hydrochloric acid, a solid at once separated; this was filtered off and crystallised from hot water, by which means it was obtained in long needles melting at 141'. The melting points of 0-, m-, and p-nitrobenzoic acids are 147', 141°, and 235' respectively. The crystals had thus the melting point of m-nitrobenzoic acid, and the analysis of the silver salt gave the following confirmatory result :

0.0998 gave 0.0396 Ag. A g - 39.68. CGH4N0,*C0,hg requires Ag = 39.39 per cent.

The filtrate from the m-nitrobenzoic acid was in one case neutralised The with ammonia and treated Kith rz solution of calcium chloride.

precipitate formed was calcium tartrate :

0,2465 gave 0.1307 CaSO,.

The tartaric acid contained in another portion of the filtrate from the. m-nitrobenzoic acid was converted into potassium hydrogen tart rate :

Ca = 15.68. CaC4H,0G,411,0 requires Ca = 15.38 per cent.

0.3475 gave 0,1666 K,S04. KHC4H406 requires K = 20.74 per cent,

I n order t o ascertain whether racemisation had occurred in the preparation, this potassium hydrogen tartrate was examined polari- metrically in aqueous solution a t 20' :

glacial acetic acid.

K = 21.50.

* Miss Hal tlc subsequently obtaineda mcalting point of 113'6' by crystallising from

N 2

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172 NITRATION OF DIETHYL MONO-P-TOLUYL-TARTRATE,

0.57 gram in 100 grams solotion : d 20°/4' = 0.9973 ; I = 299.84 mm., UD +0*36'; [.IF +21*12O.

Landolt (Opt. Dreluungsverrnogen, 2nd. edit., p. 492) gives

c = 0,615, t = 20' [ QY + 22*61',

from which i t is evident tha t the product was practically unracemised potassium hydrogen tartrate. The slight deficiency in the dextro- rotation and the high percentage of potassium were probably due to the salt containing a little potassium chloride.

Biethyl mononitro-p-tohyltartrate, obtained by nitrating diethyl mono-p-toluyltartrate in the manner described in the preparation of the corresponding benzoyl compound, exactly resembles the latter in appearance and melts at 104-105', the yield being 80-90 per cent. of the theoretical:

0.2471 gave 8.3 C.C. moist nitrogen at 15' and 751 mm. N = 3.89. 0.2565 ,, 8.95 C.C. ,, ,, 17" ,, 747 mm. N=3.70. 0.1022 ,, 0,1936 CO, and 0.0495 H,O. C = 51-66 ; H = 5-38.

C,,H,90,N requires N = 3.79 ; C = 52.03 ; H = 5-15 per cent.

The results of the polarimetric determinations made on solutions of the above are given in the table on p. 173.

By hydrolysis with alcoholic potash, tartaric and nitrotoluic acids were obtained, and these were separated from each other owing to the slight solubility of the latter in cold water. The melting point of the nitrotoluic acid was 186' (uncorr.), and corresponds closely with tha t of the nitro-p-toluic acid [Me : NO, : CO,H = 1 : 2 : 41 prepared by Ahrens (Zeit. f. Chem., 1869, 5, 104), which is stated to melt at 1 89-19O0 :

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THE HYDRATES AND THE SOLUBlLITY OF BARIUM ACETATE. 173

0-7954 0.9113 0-9048 1'4700 1'4743

0'9956 0.9865

-

1 Grams of 1 I - - - I

299'84 ,, ,, ,, ,, 9 7

,, ,,

Ethyl alcohol ...... ,, acetate ......

Chloroforni .........

Benzene ........... Pyridine ...........

,, , , . ..... , , .........

0.7957 0'7926 0'9240 0'9C81 2'4594 1'4670 1'4727 0.8855 0.9915 0.9858 0.9836

,, ...........

299.84 ,, ,, ,, ,, ,, ,, ,, ,, ,, ,,

2.3810 4.9675 2.6870 4'0420 2.8560 2.9994

9.0020 4-3900

+ 0.71" +3.60 +2'17 + 2.54 + 1.92 +_o + 1-26 + 0.71

Ethyl alcohol ...... ,, acetate ...... , Y ,, ...... 7 , , , ......

Chloroform.. .. - . .

Benzene ............ Pyridiii e ...........

, , ........ , , .........

, , ............ , y ............

2'6261 1.7370 8'9295 3'6266 7.6555 4-7648 2'9640

7'0502 4 -2367 3'1842

3 . ~ ~ 8 3 8

+ C.44" + 0-29 3.4'91 +1'55 + 5'61 + 3.50 + 2'18 - 1.12 - 4 '30 - 2.5s - 1 *93

+ 12.50" + 26.52 + 29-77 + 1 4 . 2 6 i 15 21 +o

-F 4'64 + 5'47

+ 7 'Oh" + 7.02

+ 19.85 + 1 8 7 3 + 16.74 + 16.70 + 16.66 - 10.86 - 20'51 -20 eo - 20'45

+ 44 '38" + 94-15 t 105.68 + 50'62 + 54.00 +_o +16'47 + 20'12

+ 25 .goo + 25 *go + 73.25 + 69.11 + 61.77 + 61-62 +61*47

- 75.68 - 76.01

- 40'07

- 75 '46

CHEMICAL LABOXATORY, UNIVERSITY OF BIRMINGHAM.

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