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1 Supporting Information For: Peptidic α-ketocarboxylic Acids and Sulfonamides as Inhibitors of Protein Tyrosine Phosphatases Yen Ting Chen, Jian Xie, and Christopher T. Seto* Department of Chemistry, Brown University 324 Brook St. Box, Providence, Rhode Island Table of Contents Experimental Section S2 1 and 13 C MR spectra of Compounds 6, 8-11, and S9 PLC trace of Compounds 3, 4, and S18 S1

2 Experimental Section General Methods. MR spectra were calibrated using TMS or 3- (trimethylsilyl)-1-propanesulfonic acid sodium salt (DSS) (δ = 0.00 ppm) for 1 MR and CDCl 3 (δ = 77.0 ppm), DMS (δ = 39.5 ppm), or CD 3 D (δ = 49.0 ppm) for 13 C MR. Mass spectra were recorded under fast-atom bombardment (FAB) conditions, or on an electrospray mass spectrometer. PLC analyses were performed with C18 columns and UV detection. Semi-preparative PLC was performed on the same system using a semi-preparative column ( mm). Reactions were conducted under an atmosphere of dry nitrogen in oven dried glassware. Anhydrous procedures were conducted using standard syringe and cannula transfer techniques. TF was distilled from sodium and benzophenone. Solvents were of reagent grade and were stored over 4 Å molecular sieves. All reagents were used as received. Solvent removal was performed by rotary evaporation at water aspirator pressure. Compounds 1 and 2 were obtained from commercial sources. Benzyl bromide 6. -Bromosuccinimide (BS) (1.25 g, 7.02 mmol) was added in three portions over 10 min to a solution of tert-butyl ester 5 (1.55 g, 7.02 mmol) and benzoyl peroxide (12.8 mg, mmol) in carbon tetrachloride (50 ml) that was heated at reflux. After the BS addition was complete, a second portion of benzoyl peroxide (12.8 mg, mmol) was added. The reaction was monitored by 1 MR. After all of the starting material was consumed, the reaction mixture was cooled to room temperature, washed with water (2 60 ml) and dried over MgS 4. After the solvent was removed by rotary evaporation, the residue was purified by flash column chromatography (20:1 hexanes:etac) to afford compound 6 as colorless oil (1.28 g, 4.28 mmol, 61%) which was contaminated with a small amount of the corresponding dibrominated product. This material was used in the next step without further S2

3 purification: 1 MR (400 Mz, CDCl 3 ) δ 1.64 (s, 9), 4.51 (s, 2), 7.52 (d, J = 8.2 z, 2), 7.95 (d, J = 8.2 z, 2); 13 C MR (100 Mz, CDCl 3 ) δ 28.5, 32.2, 85.4, 129.9, 130.7, 132.7, 144.9, 163.8, 186.4; RMS-ESI (M + a + ) calcd for C Bra , found Ketoester 8. A 1 M solution of LiMDS in TF (11 ml, 11 mmol) was added in one portion to a solution of compound 7 (3.69 g, 9.51 mmol) in TF (60 ml) and MPA (4 ml) that was cooled to -78 C under a nitrogen atmosphere. After stirring the reaction for 40 min, a solution of compound 6 (2.84 g, 9.51 mmol) in TF (60 ml) was added via syringe over 30 min. The mixture was stirred for an additional 3 h at -78 C, then 2 h at room temperature. The mixture was quenched with saturated aqueous 4 Cl (60 ml), extracted with EtAc (2 60 ml), and the combined organic phases were washed with 2 (60 ml), saturated aqueous 4 Cl (60 ml), and brine (60 ml). After drying over MgS 4, the solvent was evaporated and the residue was purified by flash chromatography (5:1 hexanes:etac) to give compound 8 as a colorless solid (2.61 g, 4.31 mmol, 45%): 1 MR (400 Mz, CDCl 3 ) (two conformers in a ratio of 2.9:1 were observed in the MR spectrum at 23 C) major conformer: δ 1.65 (s, 9), (m, 2), (m, 5), 6.52 (d, J = 7.5 z, 1), 6.67 (d, J = 7.4 z, 2), 6.83 (d, J = 7.2 z, 2), (m, 11), 8.00 (d, J = 8.2 z, 2); minor conformer: δ 6.62 (d, J = 7.5 z, 2), 6.74 (d, J = 7.4 z, 2), 7.90 (d, J = 8.1 z, 2); 13 C MR (100 Mz, CDCl 3 ) major conformer: δ 28.5, 39.9, 59.3, 60.7, 68.3, 79.2, 85.3, 126.8, 127.9, 128.0, 128.4, 128.5, 128.7, 129.1, 129.3, 130.8, 130.9, 130.9, 132.3, 134.1, 135.9, 143.9, 154.8, 163.9, 168.9, 186.7; minor conformer: δ 41.3, 60.8, 68.9, 79.6, 126.7, 128.4, 130.6, 134.1, 135.2, 143.3, 154.2, 168.6, 186.6; RMS-ESI (M + a + ) calcd for C a , found S3

4 Amino acid 9. Compound 8 (972 mg, 1.61 mmol) was dissolved in TF (30 ml) and Me (60 ml). To this solution was added 20% palladium hydroxide on carbon (150 mg), and the reaction was held under a hydrogen atmosphere using a balloon for 2 h. The solids were removed by filtration through a pad of celite, which was subsequently washed with Me. The filtrate was evaporated at room temperature to afford a colorless powder. This powder was washed with hexanes (3 30 ml) and dried under vacuum to give compound 9 (1:1 mixture of two diastereomers) as a white powder (435 mg, 1.47 mmol, 91%). This material was used in the next step without further purification: 1 MR (400 Mz, MeD-d 4 ) δ 1.43 (s, 9), (m, 1), (m, 1), (m, 1), 5.06 (s, 1), 7.35 (d, J = 8.0 z, 2), 7.44 (d, J = 8.0 z, 2); 13 C MR (100 Mz, MeD-d 4 ) δ 27.3, 36.8, 56.2, 73.4, 82.1, 127.4, 129.6, 136.2, 138.8, 172.8, 172.9; RMS-ESI (M + a + ) calcd for C a , found Fmoc amino acid 10. -(9-Fluorenylmethoxycarbonyl)succinimide (990 mg, 2.93 mmol) and ac 3 (947 mg, 11.3 mmol) were added to a solution of 9 (865 mg, 2.93 mmol) in dioxane (50 ml) and water (50 ml). The mixture was stirred at room temperature overnight, then cooled to 0 C. After acidifying with 1 Cl to p 3, the mixture was extracted with EtAc (2 50 ml), and the combined organic layers were washed with brine (50 ml), dried over MgS 4, and concentrated to dryness. Purification by flash column chromatography (8:1 C 2 Cl 2 :Me) gave compound 10 (1:1 mixture of two diastereomers) as a colorless foam (1.187 g, 2.30 mmol, 79%). The MR spectra of this compound are broad due to slow exchange between two conformational isomers that are present as a result of the carbamate group: 1 MR (300 Mz, CDCl 3 ) δ 1.33 (br s, 9), (br m, 2), (br m, 5), (br m, 14); 13 C MR (75 Mz, CDCl 3 ) major conformer: δ 28.2, 47.1, 55.4, 67.4, 70.3, 73.2, 83.2, 120.2, 125.6, 127.0, 127.4, 128.0, 128.3, 130.2, 137.6, 141.6, 144.2, 156.8, 173.4, 177.7; minor S4

5 conformer: δ 30.1, 47.4, 73.4, 83.4, 120.5, 127.6, 137.8, 141.7, 144.3; RMS-ESI (M + a + ) calcd for C a , found Ketoester 11. Mn 2 (5.24 g, 60.3 mmol) was added to a solution of 10 (779 mg, 1.51 mmol) in C 2 Cl 2 (25 ml). The mixture was stirred at room temperature for 2 h, then filtered through a pad of celite. The celite was washed with Me (2 40 ml), and the combined filtrates were concentrated to dryness. The residue was purified by flash chromatography (15:1 C 2 Cl 2 :Me) to give compound 11 as colorless foam (346 mg, 0.67 mmol, 45%). The MR spectra of this compound are broad due to slow exchange between conformational isomers that are present as a result of the carbamate group: 1 MR (300 Mz, CDCl 3 ) δ 1.56 (br s, 9), (br m, 7), (br m, 12); 13 C MR (75 Mz, CDCl 3 ) δ 28.2, 47.2, 53.9, 67.6, 85.2, 120.4, 125.3, 127.5, 128.2, 130.2, 130.6, 131.6, 141.6, 143.9, 164.0, 186.7; RMS-ESI (M - +, negative ion mode) calcd for C , found Sulfonate 13. To a solution of compound 12 (1.99 g, 5.60 mmol) in acetone (5 ml) was added a solution of sodium sulfite (0.925 g, 7.34 mmol) in water (50 ml). The reaction mixture was heated to reflux for 3 h, cooled, and the solvent was removed by rotary evaporation. The residue was suspended in hot ethanol and filtered. The solid was collected, washed twice with hexanes, and dried under vacuum to yield 13 (1.39 g, 3.29 mmol, 59%) as a colorless solid: 1 MR (300 Mz, DMS-d 6 ) δ 1.17 (t, J = 7.0 z, 6), 1.95 (s, 3), 3.39 (s, 2), 3.64 (s, 2), 4.15 (q, J = 7.0 z, 4), 6.84 (d, J = 8.0 z, 2), 7.20 (d, J = 8.0 z, 2), 8.07 (s, 1); 13 C MR (75 Mz, DMS-d 6 ) δ 14.7, 23.0, 38.0, 58.0, 62.6, 67.9, 130.0, 131.0, 133.7, 135.1, 167.9, 170.3; RMS-FAB (M + a + ) calcd for C a 2 8 S , found S5

6 Sulfonamide 14. To a suspension of compound 13 (1.29 g, 3.05 mmol) in methylene chloride (100 ml) was added PCl 5 (1.70 g) at 0 C. After stirring for 4.5 h, the reaction was quenched by addition of water (70 ml). The layers were separated and the aqueous layer was further extracted with two portions of methylene chloride (20 ml). The organic layers were combined, washed with brine (40 ml), and dried over a 2 S 4. The solvent was removed in vacuo to give the crude sulfonyl chloride (1.17 g). Without further purification, the crude sulfonyl chloride was dissolved in methylene chloride (40 ml) and 30% aqueous ammonium hydroxide (40 ml) was added. The mixture was stirred vigorously at 0 C for 3 h. The layers were separated, and the aqueous layer was extracted with two portions of methylene chloride (20 ml). The organic layers were combined, dried over a 2 S 4, and the solvent was removed in vacuo. The residue was washed twice with ether to yield compound 14 as a colorless solid (0.647 g, 1.61 mmol, 53%): 1 MR (300 Mz, DMS-d 6 ) δ 1.18 (t, J = 7.1 z, 6), 1.95 (s, 3), 3.44 (s, 2), 4.16 (q, J = 7.1 z, 4), 4.22 (s, 2), 6.82 (s, 2), 6.97 (d, J = 8.0 z, 2), 7.27 (d, J = 8.1 z, 2), 8.04 (s, 1); 13 C MR (75 Mz, DMS-d 6 ) δ 14.7, 23.0, 38.1, 60.7, 62.7, 67.8, 130.3, 130.7, 131.5, 135.8, 167.9, 170.3; RMS-FAB (M + a + ) calcd for C a 7 S , found Amino acid 15. Compound 14 (0.701 g, 1.75 mmol) was heated at reflux in 6 Cl solution (15 ml) for 24 h. After the reaction was cooled, the solvent was removed in vacuo and the residue was dissolved in ethanol (85 ml). Propylene oxide (2 ml) was added and the mixture was stirred at room temperature for 4 h. The colorless precipitate that formed was collected and dried under vacuum to give compound 15 (0.398 g, 1.54 mmol, 88%): 1 MR (300 Mz, D 2, DSS) δ 3.16 (dd, J = 14.5, 7.6 z, 1), 3.29 (dd, J = 14.5, 5.5 z, 1), 3.99 (dd, J = 7.4, 5.5 z, 1), 4.51 (s, 2), 7.36 (d, J = 8.0 z, 2), 7.46 (d, J = 8.0 z, 2); 13 C MR (75 Mz, D 2, DSS) δ 36.4, 56.3, 60.1, S6

7 128.8, 130.2, 131.7, 136.3, 174.1; RMS-ESI (M + + ) calcd for C S , found Fmoc amino acid 16. To a mixture of compound 15 (350 mg, 1.36 mmol) and ac 3 (643 mg, 7.65 mmol) in water (10 ml) and dioxane (3 ml) was added -(9- fluorenylmethoxycarbonyl)succinimide (560 mg, 1.66 mmol) dissolved in dioxane (7 ml). After stirring for 25 h at room temperature, the solution was acidified to p 2 with 1 Cl and extracted with three portions of ethyl acetate (50 ml). The combined organic layers were dried over a 2 S 4 and the solvent was removed under vacuum. The residue was washed twice with ether to yield 16 (550 mg, 1.14 mmol, 85%) as a colorless solid. Two additional Fmoc resonances are observed in the 13 C MR due to the slow exchange between conformational isomers of the molecule: 1 MR (300 Mz, DMSd 6 ) δ 2.89 (dd, J = 14.2, 10.4 z, 1), 3.08 (dd, J =13.6, 4.6 z, 1), 4.21 (m, 6), 6.82 (s, 2), 7.31 (m, 6), 7.41 (m, 2), 7.67 (dd, J = 7.3, 4.3 z, 2), 7.73 (d, J = 8.4 z, 1), 7.89 (d, J = 7.5 z, 2); 13 C MR (75 Mz, DMS-d 6 ) δ 36.9, 47.4, 56.3, 60.8, 66.5, 121.0, 126.1, 126.2, 127.9, 128.5, 129.7, 129.9, 131.5, 138.6, 141.5, 144.6, 144.7, 156.9, 174.2; RMS-ESI (M + + ) calcd for C S , found Peptide Synthesis. Peptides 3, 4, and 17 were prepared from amino acids 11 and 16 using Rink amide resin (substitution: 0.45 mmol/g). Resin and Fmoc derivatives of standard amino acids were obtained from ovabiochem. BTU was used as the coupling reagent in DMF (coupling time 1 h). Fmoc deprotection was performed using 50% piperidine in DMF. The resin-bound protected peptide was acetylated on its - terminus using acetic anhydride and DIEA in DMF. Resin cleavage and side-chain deprotection were performed in one step with TFA containing 2.5% 2 for peptide 3, or TFA containing 2.5% 2 and 2.5% TIS for peptides 4 and 32. To isolate the peptides, they were precipitated by dropwise addition of the mixture from the deprotection reaction S7

8 into a stirred solution of diethyl ether that was cooled in an ice bath. The precipitated crude peptides were purified by PLC using a reverse phase Rainin C 18 column with a binary solvent system of 0.1% TFA in 2 and 0.1% TFA in acetonitrile. Peptide 3. RPPLC retention time of 22.3 min using a gradient of 10-40% acetonitrile in water over 60 min at a flow rate of 0.8 ml/min; RPPLC retention time of 20.5 min using a gradient of 20-45% Me in water over 60 min at a flow rate of 0.5 ml/min; RMS-ESI (M, negative ion mode) calcd for C , found Peptide 4a. RPPLC retention time of 29.0 min using a gradient of 10-27% acetonitrile in water over 60 min at a flow rate of 1.0 ml/min; RMS-ESI (M, negative ion mode) calcd for C S , found Peptide 4b. RPPLC retention time of 41.7 min using a gradient of 5-28% acetonitrile in water over 60 min at a flow rate of 1.0 ml/min; RMS-ESI (M, negative ion mode) calcd for C S , found Peptide 17. RPPLC retention times of 55.4 and 58.9 min for the two diastereomers using an isocratic solvent system of 10% acetonitrile in water with a flow rate of 1.0 ml/min. In order to obtain a mass spectrum, the peptide was derivatized by esterification with acetyl chloride in methanol to give the tetramethyl ester; 1 RMS-ESI for the tetramethyl ester (M+4C ) calcd for C , found ) Shen, T. L.; Allison, J. J. Am. Soc. Mass Spectrom. 2000, 11, 145. S8

9 Br t-bu Figure S1. 1 MR spectrum of compound 6. Figure S2. 13 C MR spectrum of compound 6. S9

10 t-bu Cbz Ph Ph Figure S3. 1 MR spectrum of compound 8. Figure S4. 13 C MR spectrum of compound 8. S10

11 t-bu 2 Figure S5. 1 MR spectrum of compound 9. Figure S6. 13 C MR spectrum of compound 9. S11

12 t-bu Fmoc Figure S7. 1 MR spectrum of compound 10. Figure S8. 13 C MR spectrum of compound 10. S12

13 t-bu Fmoc Figure S9. 1 MR spectrum of compound 11. Figure S C MR spectrum of compound 11. S13

14 a 3 S Et 2 C C 2 Et Ac Figure S11. 1 MR spectrum for compound 13. Figure S C MR spectrum for compound 13. S14

15 2 2 S Et 2 C C 2 Et Ac Figure S13. 1 MR spectrum for compound 14. Figure S C MR spectrum for compound 14. S15

16 2 2 S Et 2 C 2 Figure S15. 1 MR spectrum for compound 15. Figure S C MR spectrum for compound 15. S16

17 2 2 S Et 2 C Fmoc Figure S17. 1 MR spectrum for compound 16. Figure S C MR spectrum for compound 16. S17

18 C 2 C 2 C 2 2 C 2 Figure S19. PLC trace of compound 3 using a reverse phase C-18 column eluted with a gradient of 10-40% MeC in water with a total of 0.1% TFA. Detection was performed at 219 nm. Figure S20. PLC trace of compound 3 using a reverse phase C-18 column eluted with a gradient of 20% to 45% Me in water. Detection was performed at 219 nm. S18

19 C 2 C 2 S C 2 Figure S21. PLC trace of Compound 4a (one diastereomer) using a reverse phase C-18 column eluted with a linear gradient from 5% to 28% C 3 C in 2 with a total of 0.1% TFA over 60 min. Detection was performed at 219 nm. Figure S22. PLC trace of Compound 4b (one diastereomer) using a reverse phase C-18 column eluted with a linear gradient from 10% to 27% C 3 C in 2 with a total of 0.1% TFA over 60 min. Detection was performed at 219 nm. S19

20 C 2 C 2 C 2 2 C 2 Figure S23. PLC trace of compound 32 using a reverse phase C-18 column eluted with 10% MeC in water with a total of 0.1% TFA. This compound is a mixture of diastereomers. Detection was performed at 219 nm. S20