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Supporting Information
General consideration
Compound 1 was synthesized according to published procedure.1 Cyclic RGDyK (RGD-containing peptide) and
neurotensin peptide (NT) (Cys-Pro-Arg-Arg-Pro-Tyr-tertLeu-Leu) was purchased from CSBio. N-Succinimidyl-S-
acetylthioacetate (SATA) and Hydroxylamine.HCl was purchased from Thermo Scientific. Glutamate-urea-lysine
(GUL) (PSMA inhibitor) was purchased from FutureChem Co., Ltd. Di-iso-propylethylamine (DIEA) was
purchased from Sigma-Aldrich. High-resolution mass spectrometry was performed by mass spectrometry core
laboratory, department of chemistry, University of North Carolina at Chapel Hill.
Synthetic Methodology
HPLC Methods
Method A: Phenomenex, Kinetex® 5μm EVO C18 100 Å, 250 x 4.6 mm LC Column. Solvent A: 0.1%TFA water;
Solvent B: 0.1%TFA acetonitrile; 0 to 2 min: isocratic elution at 5% solvent B, 2 to 22 min, 5% to 95% solvent B.
Flow rate: 1 mL/min, column temperature: 19 to 21 °C.
Method B: Phenomenex, Kinetex® 5μm EVO C18 100 Å, 250 x 4.6 mm LC Column. Solvent A: 0.1%TFA water;
Solvent B: 0.1%TFA acetonitrile; 0 to 2 min: isocratic elution at 25% solvent B, 2 to 22 min, 25% to 40% solvent B.
Flow rate: 1 mL/min, column temperature: 19 to 21 °C.
Electronic Supplementary Material (ESI) for RSC Advances.This journal is © The Royal Society of Chemistry 2017
Synthesis of the precursors
Synthesis of (11S,15S)-2,5,13-trioxo-3-thia-6,12,14-triazaheptadecane-11,15,17-tricarboxylic acid (b)
To a solution mixture of Glutamate-urea-lysine (a) (2.0 mg, 6.26 μmol) and N-Succinimidyl-S-acetylthioacetate
(SATA) (2.0 mg, 8.65 μmol) in DMSO (100 μL) was added Di-iso-propylethylamine (DIEA) (2 μL, 11.50 μmol).
The resulting mixture was incubated at room temperature for 2 h. Following reaction, the mixture was purified by
HPLC using method A to isolate chemically pure b (2.2 mg, 5.05 μmol). The identity of b was confirmed with
high-resolution mass spectrometry. HRMS calculated for C16H26N3O9S ([M+H]+):436.1390, found: 436.1377.
Figure S1. UV-HPLC profile (UV detection at 210 nm) of b.
Full scan
Zoom Inset
Figure S2. Positive-mode electrospray ionization (ESI+) mass spectra of b.
PSMA-SATA #133-159 RT: 2.04-2.44 AV: 27 NL: 2.71E6T: FTMS + p ESI Full ms [100.00-2000.00]
200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000
m/z
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436.13774z=1
871.26956z=1
214.08959z=1
391.28404z=1
927.19082z=1
481.19689z=1
672.67856z=2
1306.40548z=1
841.26042z=1
279.15905z=1
535.05563z=1
1107.81183z=2
344.08745z=?
126.70153z=?
1504.28406z=?
1954.25486z=?
1846.17094z=?
1607.39000z=?
PSMA-SATA #133-159 RT: 2.04-2.44 AV: 27 NL: 2.71E6T: FTMS + p ESI Full ms [100.00-2000.00]
434.5 435.0 435.5 436.0 436.5 437.0 437.5 438.0 438.5 439.0 439.5 440.0
m/z
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436.13774z=1
437.14183z=1
436.34181z=?
438.13446z=1437.34515
z=?439.13774
z=1436.03316
z=?
437.05515z=1
435.54441z=?
434.85677z=5
435.11914z=?
438.87796z=?
434.28280z=?
437.60481z=?
439.89946z=?
Synthesis of (((S)-1-carboxy-5-(2-mercaptoacetamido)pentyl)carbamoyl)-L-glutamic acid (2)
To a solution of b (2.2 mg, 5.05 μmol) in phosphate buffer solution pH 7.5 (100 μL) was added hydroxylamine.HCl
(1.0 mg, 14.40 μmol). The pH of the mixture was re-adjusted to pH 7.5 with 0.1 N NaOH. The resulting mixture
was then incubated at room temperature for 2 h. Following reaction, the mixture was purified by HPLC using
method A to isolate chemically pure 2 (1.9 mg, 4.83 μmol). The identity of 2 was confirmed with high-resolution
mass spectrometry. HRMS calculated for C14H24N3O8S ([M+H]+):394.1284, found: 394.1276.
Figure S3. UV-HPLC profile (UV detection at 210 nm) of 2.
Full scan
Zoom Inset
Figure S4. Positive-mode electrospray ionization (ESI+) mass spectra of 2.
PSMA-SH #113-138 RT: 1.73-2.11 AV: 26 NL: 5.65E6T: FTMS + p ESI Full ms [100.00-2000.00]
200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000
m/z
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394.12761z=1
787.24715z=1
1180.37249z=1
214.08969z=1
840.16223z=1
436.34224z=1
1002.78571z=2
1236.29200z=1
609.66274z=2
1574.50338z=2
1377.43762z=2
279.15920z=?
503.57197z=?
126.70161z=1
1140.07591z=?
346.20642z=?
1918.89192z=?
1771.06029z=2
692.40670z=?
PSMA-SH #113-138 RT: 1.73-2.11 AV: 26 NL: 5.65E6T: FTMS + p ESI Full ms [100.00-2000.00]
392.0 392.5 393.0 393.5 394.0 394.5 395.0 395.5 396.0 396.5 397.0 397.5 398.0 398.5 399.0 399.5 400.0 400.5
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394.12761z=1
395.13155z=1
396.12418z=1392.28780
z=1397.12747
z=1395.67092
z=1393.29094
z=1400.03784
z=?
393.90923z=?
394.29859z=1
394.97794z=1
395.24597z=2
396.63470z=2
392.63982z=1
398.87668z=?
399.24011z=?
400.42313z=?
397.55059z=?
398.09827z=?
Synthesis of NHC-BF3 conjugated glutamate-urea-lysine (5)
To a solution of 2 (1.9 mg, 4.83 μmol) in phosphate buffer solution pH 7.5 (50 μL) was added a solution of 1 (2.0
mg, 7.72 μmol) in MeCN (50 μL). The solution mixture was incubated at room temperature for 2h. Following
reaction, the mixture was purified by HPLC using method B to isolate chemically pure 5 (2.3 mg, 3.53 μmol). The
identity of 5 was confirmed with high-resolution mass spectrometry. HRMS calculated for C23H33BF3N6O10S
([M+H]+): 653.2024, found: 653.1999.
Figure S5. UV-HPLC profile (UV detection at 210 nm) of 5.
Full scan
Zoom inset
Figure S6. Positive-mode electrospray ionization (ESI+) mass spectra of 5.
PSMA-Carbene #173-183 RT: 2.67-2.82 AV: 11 NL: 5.45E5T: FTMS + p ESI Full ms [100.00-2000.00]
200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000
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653.19993z=1
391.28370z=1
214.08950z=1
436.34163z=1
803.54125z=1
279.15887z=1
706.11228z=1366.59097
z=2
126.70168z=3
461.58038z=?
1305.38809z=1
1097.85388z=?
988.07323z=?
1918.92796z=?
898.25000z=?
1586.08483z=?
615.44679z=?
1732.18462z=?
1433.74983z=?
PSMA-Carbene #173-183 RT: 2.67-2.82 AV: 11 NL: 5.45E5T: FTMS + p ESI Full ms [100.00-2000.00]
649.5 650.0 650.5 651.0 651.5 652.0 652.5 653.0 653.5 654.0 654.5 655.0 655.5 656.0 656.5
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653.19993z=1
652.20419z=1
654.20399z=1
651.20476z=1 655.19656
z=1650.20905z=1
656.19941z=1
652.96408z=?
653.43245z=?
653.79278z=?
651.98410z=?
652.60184z=?
650.57127z=?
651.53527z=?
649.78957z=?
654.35004z=?
655.55914z=?
649.31097z=?
Synthesis of 2-((2S,5R,8S,11S)-8-(4-(2-(acetylthio)acetamido)butyl)-11-(3-guanidinopropyl)-5-(4-hydroxybenzyl)-
3,6,9,12,15-pentaoxo-1,4,7,10,13-pentaazacyclopentadecan-2-yl)acetic acid (d)
To a solution mixture of c(RGDyK)(c) (2.0 mg, 3.23 μmol) and N-Succinimidyl-S-acetylthioacetate (SATA) (1.5
mg, 4.33 μmol) in DMSO (50 μL) was added Di-iso-propylethylamine (DIEA) (1 μL, 5.75 μmol). The resulting
mixture was incubated at room temperature for 2 h. Following reaction, the mixture was purified by HPLC using
method A to isolate chemically pure d (2.1 mg, 2.85 μmol). The identity of d was confirmed with high-resolution
mass spectrometry. HRMS calculated for C31H46N9O10S ([M+H]+):736.3088, found: 736.3045.
Figure S7. UV-HPLC profile (UV detection at 210 nm) of d.
Full scan
Zoom inset
Figure S8. Positive-mode electrospray ionization (ESI+) mass spectra of d.
RGD-SATA #156-173 RT: 2.40-2.65 AV: 18 NL: 3.90E7T: FTMS + p ESI Full ms [100.00-2000.00]
200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000
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736.30454z=1
1471.62057z=2
214.08987z=1
391.28505z=1
778.32145z=1
1104.46653z=2
694.29978z=1
508.84628z=3
1586.08825z=?
1918.92200z=?
988.07587z=?
1717.39555z=?
1384.76171z=?
1235.07846z=?
RGD-SATA #156-173 RT: 2.40-2.65 AV: 18 NL: 3.90E7T: FTMS + p ESI Full ms [100.00-2000.00]
735.5 736.0 736.5 737.0 737.5 738.0 738.5 739.0 739.5
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736.30454z=1
737.31002z=1
738.31650z=1 739.30798
z=1736.00628
z=1736.60293
z=1
736.24696z=1
736.39416z=1
735.70851z=1
737.24274z=1
737.36938z=1
736.90130z=1
737.60945z=1
738.00888z=1
738.50560z=1
738.87920z=1
739.47913z=1
Synthesis of 2-((2S,5R,8S,11S)-11-(3-guanidinopropyl)-5-(4-hydroxybenzyl)-8-(4-(2-mercaptoacetamido)butyl)-
3,6,9,12,15-pentaoxo-1,4,7,10,13-pentaazacyclopentadecan-2-yl)acetic acid (3)
To a solution of d (2.1 mg, 2.85 μmol) in phosphate buffer solution pH 7.5 (100 μL) was added hydroxylamine.HCl
(1.0 mg, 14.40 μmol). The pH of the mixture was re-adjusted to pH 7.5 with 0.1 N NaOH. The resulting mixture
was then incubated at room temperature for 2 h. Following reaction, the mixture was purified by HPLC using
method A to isolate chemically pure 3 (1.8 mg, 2.60 μmol). The identity of 3 was confirmed with high-resolution
mass spectrometry. HRMS calculated for C29H44N9O9S ([M+H]+):694.2983, found: 694.2944.
Figure S9. UV-HPLC profile (UV detection at 210 nm) of 3.
Full scan
Zoom inset
Figure S10. Positive-mode electrospray ionization (ESI+) mass spectra of 3.
RGD-SH #139-166 RT: 2.14-2.54 AV: 28 NL: 2.05E7T: FTMS + p ESI Full ms [100.00-2000.00]
200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000
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694.29444z=1
214.08974z=1
391.28455z=1
1387.59571z=2
750.21941z=1
503.57092z=?
1735.24506z=2
1060.42113z=2
1586.09035z=?
1918.96092z=?
615.47129z=?
1185.67687z=?
846.92698z=?
RGD-SH #139-166 RT: 2.14-2.54 AV: 28 NL: 2.05E7T: FTMS + p ESI Full ms [100.00-2000.00]
691 692 693 694 695 696 697 698 699 700 701 702 703
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694.29444z=1
695.29983z=1
696.30475z=1 697.29765
z=1694.02906
z=1694.55988
z=1699.42626
z=1693.28927
z=1698.30075
z=1692.38936
z=?
695.56548z=1
690.84297z=?
700.42616z=1
703.73843z=1
701.67581z=1
702.70776z=?
Synthesis of NHC-BF3 conjugated cyclic Arg-Gly-Asp-containing peptide (6)
To a solution of 3 (1.8 mg, 2.60 μmol) in phosphate buffer solution pH 7.5 (50 μL) was added a solution of 1 (2.0
mg, 7.72 μmol) in MeCN (50 μL). The solution mixture was incubated at room temperature for 2h. Following
reaction, the mixture was purified by HPLC using method A to isolate chemically pure 6 (2.0 mg, 2.10 μmol). The
identity of 6 was confirmed with high-resolution mass spectrometry. HRMS calculated for C38H53BF3N12O11S
([M+H]+): 953.3723, found: 953.3689.
Figure 11. UV-HPLC profile (UV detection at 210 nm) of 6.
Full scan
Zoom inset
Figure S12. Positive-mode electrospray ionization (ESI+) mass spectra of 6.
RGD-Carbene #179-195 RT: 2.76-3.00 AV: 17 NL: 2.88E6T: FTMS + p ESI Full ms [100.00-2000.00]
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953.36893z=1
391.28425z=1214.08966
z=1
436.34208z=1
526.64869z=2
803.54281z=1
279.15915z=1
344.78701z=3
126.70168z=?
653.88937z=3
981.33590z=2 1504.86878
z=?1185.67632
z=?1918.92406
z=?1384.72120
z=?
926.32108z=?
1762.44856z=?
1604.17529z=?
RGD-Carbene #179-195 RT: 2.76-3.00 AV: 17 NL: 2.88E6T: FTMS + p ESI Full ms [100.00-2000.00]
951.5 952.0 952.5 953.0 953.5 954.0 954.5 955.0 955.5 956.0
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953.36893z=1
954.37320z=1
952.37528z=1
955.37715z=1
956.37799z=1
953.44420z=?
953.86899z=4
952.87001z=?
953.27405z=4
954.44863z=?
954.87325z=?
954.23027z=?
953.59693z=?
955.27827z=?
952.07870z=?
955.76858z=?
951.37548z=?
952.56547z=?
955.59986z=?
951.61018z=?
952.24840z=4
956.08139z=?
Synthesis of NHC-BF3 conjugated neurotensin peptide (7)
To a solution of neurotensin peptide 4 (3 mg, 2.80 μmol) in phosphate buffer solution pH 7.5 (50 μL) was added a
solution of 1 (2.0 mg, 7.72 μmol) in MeCN (50 μL). The solution mixture was incubated at room temperature for 2h.
Following reaction, the mixture was purified by HPLC using method B to isolate chemically pure 7 (2.5 mg, 1.88
μmol). The identity of 6 was confirmed with high-resolution mass spectrometry. HRMS calculated for
C58H90BN17O13SF3 ([M]+): 1332.6670, found: 1332.6725, calculated for C58H91BN17O13SF3 ([M+H]2+) m/z :
666.8374, found 666.8360.
Figure 13. UV-HPLC profile (UV detection at 210 nm) of 7.
Full scan
Zoom inset
Figure S14. Positive-mode electrospray ionization (ESI+) mass spectra of 7.
Cys-NT-Carbene #215-240 RT: 3.32-3.69 AV: 26 NL: 1.85E7T: FTMS + p ESI Full ms [100.00-2000.00]
200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000
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666.83602z=2
1332.67246z=2
391.28470z=1
214.08977z=1
632.83598z=2
1073.59620z=1
715.36476z=2
889.11816z=3
503.56921z=?
1504.80722z=?
1185.67508z=?
1919.04638z=?
1384.75666z=?
1795.92095z=1
1654.79680z=?
1288.44371z=?
Cys-NT-Carbene #215-240 RT: 3.32-3.69 AV: 26 NL: 1.85E7T: FTMS + p ESI Full ms [100.00-2000.00]
666.0 666.5 667.0 667.5 668.0 668.5 669.0 669.5 670.0 670.5 671.0
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666.83602z=2
667.33776z=2
667.83980z=2
666.33934z=2
668.34213z=2 668.84266
z=2669.33898
z=2667.08037
z=2667.58352
z=2
666.74656z=2
670.75235z=2
666.25609z=2
667.98816z=2
669.84085z=2
665.77276z=2
670.47507z=?
671.17103z=?
Radiochemistry experiments
All chemicals are analytical grade and used without further purification. Analytical reversed-phase high-
performance liquid chromatography (HPLC) was accomplished on a SHIMADZU chromatography system (Model
CBM-20A). The λ absorbance detector and the model 2200 scaler ratemeter radiation detector were added to the
HPLC system. HPLC was performed on a Phenomenex, Kinetex® 5μm EVO C18 100 Å, 250 x 4.6 mm LC Column
with a flow of 1 ml/min.
Radiochemistry
The radiolabeling reactions were performed using the following protocol. The lyophilized 5, 6 or 7 powder (~ 0.30
μmol) was mixed with SnCl4 ( 1 μL) in 25 μL of anhydrous MeCN. The resulting solution was then combined with
[18F]-TBAF in MeCN. After incubating at 70 °C for 10 min, the reaction was quenched by adding 1 mL of water.
The mixture was passed through a Sep-Pak light alumina N cartridge. An aliquot of aqueous fraction was analyzed
by HPLC using method A for [18F]-6 and method B for [18F]-5 and [18F]-7. The identity of [18F]-NHC-BF3
conjugates ([18F]-5, [18F]-6, and [18F]-7) was confirmed by the comparison of their retention times with those of
reference compounds (5, 6 and 7) (Figure S15).
Figure S15. UV HPLC profiles of 5 (A), 6 (B), and 7 (C) as the reference compounds and radio HPLC profiles of
the crude [18F]-5 (D), [18F]-6 (E) and [18F]-7 (F) obtained after passing through Sep-Pak alumina N cartridge.
Table S1. radiosynthesis table for [18F]-5, [18F]-6, and [18F]-7.
Entry cpd Radiochemical yield
determination a
Specific activity
determination b
Starting 18F-activity
(GBq)
18F-activity of
the isolated
product (GBq)
Radiochemical
yield (%)
18F-Activity of
the product at
the end of
synthesis (EOS)
(GBq)
Amount
of cpd
(μmol)
Specific
activity
(GBq/μmol)
1 5 5.92 1.75 29.6 0.078 0.013 6.0
2 6 5.62 1.44 25.6 0.096 0.027 3.5
3 7 5.85 1.25 21.4 0.085 0.025 3.4 aRadiochemical yield (RCY) is determined by dividing the 18F-activity of the isolated product by the starting 18F
activity. bA fraction of isolated 18F-product was re-injected to HPLC for specific activity determination. Then, the
specific activity (SA) is determined by dividing the isolated product activity by the amount of the product (based on
the integration of UV-HPLC profile and compare it with the standard calibration curve). The radiochemical yields
were decay corrected. The specific activities were measured at the end of synthesis (EOS).
In vitro stability test
After HPLC purification, a fraction of purified [18F]-5, [18F]-6, or [18F]-7 were re-injected into the HPLC to confirm
that only single radio peak was obtained at the starting point. Then, the probes were adjusted to pH 7 with 0.1N
NaOH. Then, 10X PBS was added to each solution to reconstruct the solution to 1X PBS. After 1 hour and 2 hours
incubation at room temperature, a fraction of each probe (0.0019 GBq) was injected into the HPLC. The radio purity
was calculated based on the integration of the product peak and other minor peaks.
Figure S16. Radio-HPLC profiles of [18F]-5, [18F]-6, and [18F]-7 after incubation in phosphate buffer solution (PBS)
pH=7.5 for 1 hour (A, B, and C) and 2 hours (D, E, and F)
In vivo PET/CT Imaging
For PET image acquiring, each nude mice was injected with 0.0037 GBq of [18F]-5, [18F]-6, or [18F]-7 in 1X PBS
pH 7.5 (300 μL) via the tail vein. At each post-injection time point, the mice were anesthetized using isoflurane (2%
in oxygen), then placed on the imaging cradle with body temperature maintained. The static PET/CT acquisition
were then achieved and reconstructed for analysis.
PET quantifications
For each microPET scan, regions of interest (ROIs) were drawn over the normal tissues and major organs using
AMIDE 0.9.0 software on decay-corrected coronal images. The average radioactivity concentration (accumulation)
within an organ was obtained from the mean pixel values within the multiple region of interest volume, which were
converted to counts/mL/min using a conversion factor. Assuming a tissue density of 1 g/mL, the ROIs were
converted to counts/g/min and then divided by the administered activity to obtain an imaging derived %ID/g.
Table S2. PET quantification (%ID/g) of [18F]-6 in nude mice bearing U87MG at 0.5 h post-injection.
Organs [18F]-6
(%ID/g)
(n=3)
Tumor 1.50 ± 0.01
Liver 1.189 ± 0.04
Kidneys 2.77 ± 0.23
Muscle 0.15 ± 0.01
Table S3. PET quantification (%ID/g) of [18F]-7 in nude mice bearing PANC1 at 1 h post-injection.
Organs [18F]-7
(%ID/g)
(n=3)
Tumor 0.54 ± 0.03
Liver 0.086 ± 0.006
Kidneys 0.94 ± 0.10
Muscle 0.059 ± 0.006
1 K. Chansaenpak, M. Wang, Z. Wu, R. Zaman, Z. Li and F. P. Gabbai, Chem. Commun., 2015, 51,
12439-12442.