Preparation of N-substituted N-Arylsulfonylglycines and their Use in Peptoid Synthesis

Transcription

1 - Supporting Information (SI) - Preparation of N-substituted N-Arylsulfonylglycines and their Use in Peptoid Synthesis Steve Jobin, Simon Vézina-Dawod, Claire Herby, Antoine Derson and Eric Biron* Faculty of Pharmacy, Université Laval, Pavillon Ferdinand-Vandry, Québec (QC), G1V 0A6, Canada and Laboratory of Medicinal Chemistry, Centre de recherche du Centre Hospitalier Universitaire de Québec (CHUL Section), 2705 Boulevard Laurier, Québec, Québec (QC) G1V 4G2, Canada eric.biron@pha.ulaval.ca

2 Table of contents 1 Materials and equipment Synthesis of tert-butyl (4-aminobutyl) carbamate (1h*) General procedure for the synthesis of o-nitrobenzenesulfonamides (2a-c, 2e-f and h-i) Synthesis of N-(4-hydroxyphenethyl)-o-nitrobenzenesulfonamide (2d) Synthesis of N-(o-nitrobenzenesulfonyl)-propanoic acid (2g) Synthesis of N-(tert-butoxyalkyl)-o-nitrobenzenesulfonamides (3a-f) Synthesis of N-(o-nitrobenzenesulfonyl)-propanoic allyl ester (3g) General procedure for the N-alkylation of side chain protected o-nitrobenzenesulfonamides (3i and 4a-h) S6 Synthesis of tert-butyl 2-(2-((N-(2-methoxy-2-oxoethyl)-2-nitrophenyl)sulfonamido)ethyl)-1H-indole-1- carboxylate (4i) Synthesis of methyl methyl (Z)-6-((tert-butoxycarbonyl)amino)-2,2-dimethyl-12-((2-nitrophenyl)sulfonyl)-4- oxo-3-oxa-5,7,12-triazatetradec-5-en-14-oate (4j) S8 Synthesis of side chain protected N-substituted N-o-nitrobenzenesulfonylglycines (5a-f and 5h-j) Synthesis of N-(3-(allyloxy)-3-oxopropyl)-N-((2-nitrobenzenesulfonyl) glycine (5g) Synthesis of side chain amide derivatives (7a-c) Peptoid and Peptomer synthesis Table S1. Sequence, characterization data and yields for peptoid oligomers 8-11 Table S2. Sequence fragments observed by MS-MS from peptoid oligomers in Da Figure S1. HPLC traces (λ = 220 nm) and MS (ESI-) of the final ons-nsg monomers (5a-j) Figure S2. 1 H NMR and 13 C NMR spectra of the final monomers (5a-j) Figure S3. LC-MS-MS characterization for peptoid (8a-m, 9-11) S3 S3 S3 S4 S5 S5 S6 S8 S9 S10 S11 S13 S14 S15 S16 S23 S33 S2

3 Materials and equipment All the chemical reagents and solvents from commercial sources were used without further purification. Coupling reagents and amino acid derivatives were purchased from Matrix Innovation Inc. (Quebec, QC, Canada). Rink Amide AM resin (0.56 mmol/g) was purchased from ChemImpex (Wood Dale, IL, USA). All other reagents and solvents were purchased from Sigma-Aldrich (St. Louis, MO, USA). Reactions on solid support were performed in filter columns (2 ml) from Roland Vetter Laborbedarf OHG (Ammerbuch, Germany). Flash chromatography was performed on silica gel F60 ( mesh) from SiliCycle (Quebec, QC, Canada). 1 H and 13 C NMR spectra were obtained in CDCl 3, CD 3 OD, (CD 3 ) 2 SO or (CD 3 ) 2 CO as solvent and internal reference on a Bruker AVANCE 400 spectrometer (Billerica, MA, USA). RP-HPLC analyses were conducted on a Shimadzu Prominence instrument (Columbian, MD, USA) using a Phenomenex Kinetex column (4.6 mm x 100 mm, 2.6 µm XB-C 18, 100 Å, 1.8 ml/min) with a 10.5 min gradient from water (0.1% TFA) and CH 3 CN (0.1% TFA) (CH 3 CN %) and detection at 220 nm and 254 nm. Mass spectrometry was performed on a Waters Synapt G2-Si (Quadrupole/TOF) with a Waters UPLC binary pump and FTN injector. The mass spectrometer was operated in High resolution mode. The mass spectrometer calibration was performed with a sodium formate (Sigma) solution and lock-mass correction was performed using a Leucine-enkephaline solution (Waters). Synthesis of tert-butyl (4-aminobutyl) carbamate (1h*) A solution of (Boc) 2 O (9.4 mmol, 0.1 equiv.) in CHCl 3 (50 ml) was added dropwise on 2 h to 1,4- diaminobutane (94.4 mmol) in CHCl 3 (100 ml) and the reaction was stirred overnight. The organic layer was then washed with water (3 x 30 ml) and dried over MgSO 4. The solvent was removed under reduced pressure to provide the desired pure product as a colorless oil (1.767 g, quantitative); 1 H NMR (400 MHz, CDCl 3 ) δ 4.82 (s, 1H), 3.05 (q, J = 5.64 Hz, 2H), 2.64 (t, J = 6.76 Hz, 2H), (m, 13H), 1.24 (s, 2H). 13 C NMR (101 MHz, CDCl 3 ) δ (Cq), (Cq), (Cq), (CH 2 ), (CH 2 ), (CH 2 ), (CH 3 ), (CH 2 ). General procedure for the synthesis of o-nitrobenzenesulfonamides (2a-c, 2e-f and h-i) The functionalized amine was dissolved in CH 2 Cl 2 (1 M) followed by the addition of Et 3 N (2.5 equiv). The resulting mixture was stirred at room temperature for 30 min and a solution of o-nitrobenzenesulfonyl chloride (0.85 equiv) in CH 2 Cl 2 (0.85 M) was added slowly. The reaction was monitored by TLC (3% MeOH/CH 2 Cl 2 ) and quenched with a 0.1M HCl solution. Following aqueous phase extraction with CH 2 Cl 2 (3 ), the combined organic layers were washed with brine and dried over MgSO 4. The solvent was removed under reduced pressure and the crude product was used for the next step or purified by flash chromatography on silica gel with 3% MeOH/CH 2 Cl 2 to afford the pure desired compound. N-(3-hydroxypropyl)-o-nitrobenzenesulfonamide (2a). Pale yellow oil (2.901 g, 99%); 1 H NMR (400 MHz, CDCl 3 ) δ (m, 1H), (m, 1H), (m, 2H), 5.78 (s, 1H), 3.78 (t, J = 5.6 Hz, 2H), 3.26 (q, J = 5.9 Hz, 2H), 1.79 (m, 2H), 1.65 (br s, 1H). 13 C NMR (101 MHz, CDCl 3 ) δ (CH), (Cq), (CH), (CH), (CH), (CH 2 ), (CH 2 ), (CH 2 ). RP- HPLC t R = 6.08 min. (±)-N-(2-hydroxypropyl)-o-nitrobenzenesulfonamide (2b). Pale yellow oil (182.0 mg, 82%); 1 H NMR (400 MHz, CDCl 3 ) δ (m, 1H), 7.86 (m, 1H), (m, 2H), 5.81 (br s, 1H), 3.95 (m, 1H), 3.21 (d, J = 12.8 Hz, 1H), 2.94 (dd, J = 12.8, 8.1 Hz, 1H), 2.18 (br s, 1H), 1.19 (d, J = 6.3 Hz, 3H). 13 C NMR (101 MHz, CDCl 3 ) δ (Cq), (CH), (Cq), (CH), (CH), (CH), (CH), (CH 2 ), (CH 3 ). RP-HPLC t R = 6.36 min. S3

4 (R)-N-(1-hydroxypropan-2-yl)-o-nitrobenzenesulfonamide (2c). Pale yellow oil (139.8 mg, 73%); 1 H NMR (400 MHz, CDCl 3 ) δ (m, 1H), (m, 1H), (m, 2H), 5.54 (s, 1H), 3.61 (d, J = 8.6 Hz, 2H), (m, 1H), 2.04 (s, 1H), 1.13 (d, J = 6.7 Hz, 3H). 13 C NMR (101 MHz, CDCl 3 ) δ (CH), (Cq), (CH), (CH), (CH), (CH 2 ), (CH), (CH 3 ). RP-HPLC t R = 6.22 min. N-((1R,2R)-2-hydroxycyclopentyl)-o-nitrobenzenesulfonamide (2e). Pale yellow oil (182.5 mg, 75%); 1 H NMR (400 MHz, CDCl 3 ) δ (m, 1H), (m, 1H), (m, 2H), 5.39 (d, J = 5.3 Hz, 1H), 4.11 (dq, J = 6.8, 4.3, 2.8 Hz, 1H), 3.43 (m, 1H), 2.38 (d, J = 2.9 Hz, 1H), 2.02 (m, 2H), 1.70 (m, J = 13.9, 8.2, 5.6, 2.3 Hz, 2H), (m, 1H), 1.46 (m, J = 13.2, 8.1 Hz, 1H). 13 C NMR (101 MHz, CDCl 3 ) δ (Cq), (Cq), (CH), (CH), (CH), (CH), (CH), (CH), (CH 2 ), (CH 2 ), (CH 2 ). RP-HPLC t R = 7.00 min. N-((1R,4R)-4-hydroxycyclohexyl)-o-nitrobenzenesulfonamide (2f). Pale yellow oil (1.73 g, 78%); 1 H NMR (400 MHz, CDCl 3 ) δ (m, 1H), (m, 1H), (m, 2H), 5.20 (d, J = 7.4 Hz, 1H), 3.60 (m, 1H), (m, 1H), (m, 4H), 1.46 (s, 1H), 1.31 (m, 4H). 13 C NMR (101 MHz, CDCl 3 ) δ (Cq), (CH), (CH), (CH), (CH), (CH), (CH), (CH 2 ), (CH 2 ). RP-HPLC t R = 6.86 min. N-(4-tert-butoxycarbonylaminobutyl)-o-nitrobenzenesulfonamide (2h). White solid (935.2 mg, 96%); %); 1 H NMR (400 MHz, CDCl 3 ) δ (m, 1H), (m, 1H), (m, 2H), 5.30 (s, 1H), 4.52 (s, 1H), (m, 4H), (m, 4H), 1.43 (s, 9H). 13 C NMR (101 MHz, CDCl 3 ) δ (Cq), (Cq), (CH), (Cq), (CH), (CH), (CH), (Cq), (CH 2 ), (CH 2 ), (CH 3 ), (CH), (CH). RP-HPLC t R = 9.22 min. N-(2-(1H-indol-2-yl)ethyl)-o-nitrobenzenesulfonamide (2i). Pale yellow solid (1,02 g, 93%); 1 H NMR (400 MHz, CDCl 3 ) δ (m, 2H), (m, 3H), (m, 2H), 7.14 (t, J = 7.32 Hz, 1H), 7.02 (d, J = 2,12 Hz, 1H), 6.97 (t, J = 7.72 Hz, 1H), 5.35 (t, J = 5.16 Hz, 1H), 3.45 (q, J = 6.48 Hz, 2H), 3.01 (t, J = 6.6 Hz, 2H). 13 C NMR (101 MHz, CDCl 3 ) δ (Cq), (CH), (CH), (CH), (Cq), (CH), (CH), (CH), (CH), (CH), (CH), (Cq), (CH 2 ), (CH 2 ). RP-HPLC t R = 9.46 min. Synthesis of N-(4-hydroxyphenethyl)-o-nitrobenzenesulfonamide (2d) o-nitrobenzenesulfonyl chloride (1.110 g, 5 mmol) was dissolved in dry THF (3 ml) and stirred at 0 C. Tyramine (686 mg, 5 mmol) was dissolved in a solution of dry THF/DMF (5:1) (6 ml) and added dropwise to the o-nitrobenzenesulfonyl chloride solution over 30 minutes. After stirring for 1 h at room temperature, dry Na 2 CO 3 (530 mg, 5 mmol) was added and the resulting mixture stirred for 3 h. The solvent was removed under vacuum and the product was redissolved in a mixture of 2M HCl (10 ml) and brine (10 ml). After extracting the aqueous phase with EtOAc (3 10 ml), the combined organic layers were washed with brine and dried over MgSO 4. The solvent was removed under reduced pressure and the desired compound obtained as a yellow powder (1.176 g, 73%); 1 H NMR (400 MHz, (DMSO-d 6 ) δ (br s, 1H), 8.13 (t, J = 5.6 Hz, 1H), (m, 2H), (m, 2H), 6.93 (d, J = 8.4 Hz, 2H), 6.62 (d, J = 8.4 Hz, 2H), (m, 2H), 2.60 (t, J = 7.5 Hz, 2H). 13 C NMR (101 MHz, DMSO-d 6 ) δ (Cq), (Cq), (CH), (Cq), (CH), (CH), (CH), (CH), (CH), (CH), (CH 2 ), (CH 2 ). RP-HPLC t R = 8.36 min. S4

5 Synthesis of N-(o-nitrobenzenesulfonyl)-propanoic acid (2g) β-alanine (1.723 g, 19.3 mmol) was dissolved in 1N NaOH and the mixture was cooled in an ice bath. A solution of o-nitrobenzenesulfonyl chloride (4.464 g, 20.1 mmol) was then added dropwise to the cooled mixture by taking care that the ph does not drop under 9. The reaction was monitored by TLC (10% MeOH in DCM). After completion, the aqueous solution was washed with EtOAc before being acidified with 1N HCl (ph = 2). Then the aqueous phase was extracted with EtOAc (3 x 25 ml) and the organic layers were combined, washed with brine and dried over MgSO 4. The solvent was removed under reduced pressure and the crude product was used in the next step without further purification. Pale yellow oil (4.659 g, 88%) 1 H NMR (400 MHz, DMSO-d 6 ) δ 8.51 (s, 1H), (m, 1H), (m, 3H), 6.71 (t, J = 5.32 Hz, 1H), 3.37 (q, J = 6.6 Hz, 2H), 2.62 (t, J = 6.64 Hz, 2H). 13 C NMR (101 MHz, (DMSO-d 6 ) δ (Cq), (CH), (Cq), (CH), (CH), (CH), (CH 2 ), (CH 2 ). RP-HPLC t R = 6.58 min. Synthesis of N-(tert-butoxyalkyl)-o-nitrobenzenesulfonamides (3a-f) Mg(ClO 4 ) 2 (0.1 equiv) was activated for 2 h at 130 C under vacuum in a round bottom flask and then cooled to room temperature under argon. The o-nitrobenzenesulfonamide (2a-f) was dissolved in CH 2 Cl 2 at a concentration of approximately 0.8 M and added to the activated Lewis acid. Afterward, Boc 2 O (2.3 equiv) was added and the resulting mixture was refluxed overnight at 50 C and then, quenched with water. After extraction with CH 2 Cl 2 (3 25 ml), the combined organic layers were washed with brine and dried over MgSO 4. The solvent was removed under reduced pressure and the crude product purified by flash chromatography on silica gel with 50% Et 2 O/hexanes to afford the desired compound. N-(3-(tert-butoxy)propyl)-o-nitrobenzenesulfonamide (3a). Brown oil (65.4 mg, 49%); 1 H NMR (400 MHz, CDCl 3 ) δ (m, 1H), (m, 1H), 7.73 (qd, J = 4.7, 4.2, 2.1 Hz, 3H), (br S, 1H), 3.43 (t, J = 5.6 Hz, 2H), (m, 2H), (m, 2H), 1.17 (s, 9H). 13 C NMR (101 MHz, CDCl 3 ) δ (Cq), (Cq), (CH), (CH), (CH), (CH), (Cq), (CH 2 ), (CH 2 ), (CH 2 ), (CH 3 ). RP-HPLC t R = 9.55 min. (±)-N-(2-(tert-butoxy)propyl)-o-nitrobenzenesulfonamide (3b). Pale yellow solid (1.21 g, 58%); 1 H NMR (400 MHz, CDCl 3 ) δ (m, 1H), (m, 1H), (m, 2H), 5.71 (dd, J = 7.1, 3.6 Hz, 1H), 3.85 (m, 1H), 3.12 (m, 1H), 2.81 (m, 1H), 1.19 (s, 9H), 1.12 (d, J = 6.2 Hz, 3H). 13 C NMR (101 MHz, CDCl 3 ) δ (Cq), (Cq), (CH), (CH), (CH), (CH), (Cq), (CH), (CH 2 ), (CH 3 ), (CH 3 ). RP-HPLC t R = 9.70 min. (R)-N-(1-(tert-butoxy)propan-2-yl)-o-nitrobenzenesulfonamide (3c). Pale yellow solid (102.3 mg, 60%); 1 H NMR (400 MHz, CDCl 3 ) δ (m, 1H), (m, 1H), (m, 2H), 5.78 (d, J = 6.2 Hz, 1H), 3.57 (qd, J = 6.5, 4.3 Hz, 1H), (m, 2H), 1.21 (d, J = 6.6 Hz, 2H), 1.02 (s, 7H). 13 C NMR (101 MHz, CDCl 3 ) δ (Cq), (CH), (CH), (CH), (CH), (Cq), (CH 2 ), (CH), (CH 3 ), (CH 3 ). RP-HPLC t R = 9.99 min. N-(4-(tert-butoxy)phenethyl)-o-nitrobenzenesulfonamide (3d). White powder (201.2 mg, 57%); 1 H NMR (400 MHz, CDCl 3 ) δ (m, 1H), (m, 1H), (m, 2H), 6.97 (d, J = 8.4 Hz, 2H), 6.86 (d, J = 8.4 Hz, 2H), 5.31 (t, J = 5.7 Hz, 1H), 3.36 (q, J = 6.9 Hz, 2H), 2.79 (t, J = 7.0 Hz, 2H), 1.31 (s, 9H). 13 C NMR (101 MHz, CDCl 3 ) δ (Cq), (Cq), (CH), (CH), (Cq), (CH), (CH), (CH), (CH), (Cq), (CH 2 ), (CH 2 ), (CH 3 ). RP-HPLC t R = min. S5

6 N-((1R,2R)-2-(tert-butoxy)cyclopentyl)-o-nitrobenzenesulfonamide (3e). White powder (1.20 g, 64%); 1 H NMR (400 MHz, CDCl 3 ) δ (m, 1H), (m, 1H), (m, 2H), 5.45 (d, J = 4.5 Hz, 1H), 3.79 (q, J = 6.8 Hz, 1H), (m, 1H), 2.03 (m, 1H), (m, 1H), (m, 2H), (m, 2H), 1.09 (s, 9H). 13 C NMR (101 MHz, CDCl 3 ) δ (Cq), (Cq), (CH), (CH), (CH), (CH), (CH), (Cq), (CH), (CH 2 ), (CH 2 ), (CH 3 ), (CH 2 ). RP-HPLC t R = min. N-((1r,4r)-4-(tert-butoxy)cyclohexyl)-o-nitrobenzenesulfonamide (3f). White powder (67.1 mg, 49%); 1 H NMR (400 MHz, CDCl 3 ) δ (m, 1H), 7.87 (m, 1H), (m, 2H), 5.15 (d, J = 7.4 Hz, 1H), 3.30 (m, 2H), (m, 2H), (m, 2H), 1.29 (m, 4H), 1.15 (s, 9H). 13 C NMR (101 MHz, CDCl 3 ) δ (Cq), (Cq), (CH), (CH), (CH), (CH), (Cq), (CH), (CH), (CH 2 ), (CH 2 ), (CH 3 ). RP-HPLC t R = 6.85 min. Synthesis of N-(o-nitrobenzenesulfonyl)-propanoic allyl ester (3g) N-(o-nitrobenzenesulfonyl)-propanoic acid (2g) (453 mg, 1.65 mmol), p-toluene sulfonic acid (345 mg, 1.81 mmol) and allyl alcohol (574 mg, 9.9 mmol) were dissolved in benzene (20 ml). The mixture was reflux at 110 C in a Dean-Stark filled with benzene and the reaction monitored by TLC (40 % EtOAc in hexanes). After completion, the benzene was removed under reduced pressure and the obtained brown product purified by flash chromatography 40 % EtOAc in hexanes. The desired product was isolated as a pale yellow oil. (423 mg, 81%); 1 H NMR (400 MHz, CDCl 3 ) δ (m, 1H), (m, 1H), (m, 2H), 5.98 (t, J = 6.16 Hz, 1H), (m, 1H), (m, 2H), 4.58 (dt, J = 3.36, 1.24 Hz, 2H), 3.38 (q, J = 6.24 Hz, 2H), 2.63 (t, J = 6.12 Hz, 2H). 13 C NMR (101 MHz, CDCl 3 ) δ (Cq), (Cq), (CH), (Cq), (CH), (CH), (CH), (CH), (CH 2 ), (CH 2 ), (CH 2 ), (CH 2 ). RP-HPLC t R = 8.83 min. General procedure for the N-alkylation of side chain protected o-nitrobenzenesulfonamides (3i and 4a-h) Protected submonomer (3a-h) or tryptamine (2i) was dissolved in anhydrous DMF (0.1 M) in presence of K 2 CO 3 (2 equiv) under argon. The mixture was stirred for 15 minutes before the addition of the methyl bromoacetate (1.5 equiv for 3a-g and 3h or 1 equiv for 2i) or tert-butyl bromoacetate for 3g. The solution was stirred for 3 h at room temperature and quenched with water. The aqueous phase was extracted 3 times with CH 2 Cl 2. The combined organic layers were then washed twice with 5% NaHCO 3 and once with brine and dried over MgSO 4. The solvent was removed under vacuum and the crude product used without further purification. N-(2-(1H-indol-2-yl)ethyl)-N-(o-nitrobenzenesulfonyl) methyl glycinate (3i). Yellow oil (570 mg, 87%); 1 H NMR (400 MHz, CDCl 3 ) δ 8.04 (d, J = 7.92 Hz, 1H), 7.87 (d, J = 7.88 Hz, 1H), (m, 2H), 7.45 (d, J = 7.6 Hz, 1H), 7.38 (t, J = 7.28 Hz, 1H), (m, 2H), (m, 1H), 4.28 (s, 2H), (m, 5H), 2.96 (t, J = 7.28 Hz, 2H), 1.66 (s, 9H). 13 C NMR (101 MHz, CDCl 3 ) δ (Cq), (Cq), (Cq), (CH), (Cq), (CH), (CH), (CH), (CH), (CH), (CH), (CH), (Cq), (CH), (CH 2 ), (CH 3 ), (CH 2 ), (CH 3 ), (CH 2 ). RP-HPLC t R = 9.84 min. N-(3-(tert-butoxy)propyl)-N-(o-nitrobenzenesulfonyl) methyl glycinate (4a). Yellow oil (324 mg, quantitative); 1 H NMR (400 MHz, CDCl 3 ) δ (m, 1H), (m, 2H), (m, 1H), S6

7 4.24 (s, 2H), 3.66 (s, 3H), 3.49 (t, J = 7.16 Hz, 2H), 3.33 (t, J = 6.08 Hz, 2H), 1.76 (m, 2H), 1.13 (s, 9H). 13 C NMR (101 MHz, CDCl 3 ) δ (Cq), (Cq), (CH), (Cq), (CH), (CH), (CH), (Cq), (CH 2 ), (CH 3 ), (CH 2 ), (CH 2 ), (CH 2 ), (CH 3 ). RP-HPLC t R = 9.83 min. (±)N-(2-(tert-butoxy)propyl)-N-(o-nitrobenzenesulfonyl) methyl glycinate (4b). Yellow oil (630 mg, quantitative); 1 H NMR (400 MHz, CDCl 3 ) δ (m, 1H), (m, 2H), (m, 1H), 4.46 (dd, J = 63.16, Hz, 2H), (m, 1H), 3.58 (s, 3H), (m, 1H), 3.17 (q, J = 7.28 Hz, 1H), 1.17 (s, 9H), 1.09 (d, J = 6.24 Hz, 3H). 13 C NMR (101 MHz, CDCl 3 ) δ (Cq), (Cq), (CH), (Cq), (CH), (CH), (CH), (Cq), (CH), (CH 2 ), (CH 3 ), (CH 2 ), (CH 3 ), (CH 3 ). RP-HPLC t R = min. (R)-N-(1-hydroxypropan-2-yl)-o-nitrobenzenesulfonamide methyl glycinate (4c). White solid (172 mg, 98%); 1 H NMR (400 MHz, CDCl 3 ) δ (m, 1H), (m, 3H), 4.22 (dd, J = 47.48, Hz, 2H), (m, 1H), 3.69 (s, 1H), 3.45 (dd, J = 5.76, 3.84, 1H), 3.30 (dd, J = 5.24, 4.36 Hz, 1H), 1.17 (d, J = 6.88 Hz, 3H), 1.04 (s, 9H). 13 C NMR (101 MHz, CDCl 3 ) δ (Cq), (Cq), (Cq), (CH), (CH), (CH), (CH), (CH), (Cq), (CH 2 ), (CH), (CH 3 ), (CH 2 ), (CH 3 ), (CH 3 ). RP-HPLC t R = min. N-(4-(tert-butoxy)phenethyl)-N-(o-nitrobenzenesulfonyl) methyl glycinate (4d). Yellow oil (180 mg, quantitative); 1 H NMR (400 MHz, CDCl 3 ) δ (m, 1H), (m, 2H), (m, 2H), (m, 2H), (m, 2H), 4.10 (s, 2H), 3.64 (s, 3H), 3.60 (t, J = 7.52 Hz, 2H), 2.84 (t, J = 7.84 Hz, 2H), 1.31 (s, 9H). 13 C NMR (101 MHz, CDCl 3 ) δ (Cq), (Cq), (Cq), (CH), (Cq), (Cq), (CH), (CH), (CH), (CH), (CH), (Cq), (CH 3 ), (CH 2 ), (CH 2 ), (CH 2 ), (CH 3 ). RP-HPLC t R = min. N-((1R,2R)-2-(tert-butoxy)cyclopentyl)-N-(o-nitrobenzenesulfonyl) methyl glycinate (4e). Yellow oil (365 mg, quantitative); 1 H NMR (400 MHz, CDCl 3 ) δ (m, 1H), (m, 3H), 4.40 (d, J = 18.5 Hz, 1H), (m, 2H), 3.85 (q, J = 7.92 Hz, 1H), 3.70 (s, 3H), (m, 1H), (m, 1H), (m, 2H), (m, 2H), 0.94 (s, 9H). 13 C NMR (101 MHz, CDCl 3 ) δ (Cq), (Cq), (Cq), (CH), (CH), (CH), (CH), (Cq), (CH), (CH), (CH 3 ), (CH 2 ), (CH 2 ), (CH 3 ), (CH 2 ), (CH 2 ). RP-HPLC t R = min. N-((1R,4R)-4-(tert-butoxy)cyclohexyl)-N-(o-nitrobenzenesulfonyl) methyl glycinate (4f). Yellow oil (369 mg, quantitative); 1 H NMR (400 MHz, CDCl 3 ) δ (m, 1H), (m, 2H), (m,1h), 4.09 (s, 2H), 3.70 (s, 4H), (m, 1H), (m, 4H), (m, 4H), 1.14 (s, 9H). 13 C NMR (101 MHz, CDCl 3 ) δ (Cq), (Cq), (CH), (Cq), (CH), (CH), (CH), (Cq), (CH), (CH 2 ), (CH), (CH 3 ), (CH 2 ), (CH 2 ), (CH 2 ), (CH 3 ), (CH 2 ). RP-HPLC t R = min. Allyl 3-((N-(2-(tert-butoxy)-2-oxoethyl)-o-nitrobenzene)sulfonamido)propanoate (4g). Yellow oil (501.6 mg, 80%); 1 H NMR (400 MHz, CDCl 3 ) δ (m, 1H), (m, 2H), (m, 1H), (m, 1H), (m, 2H), 4.56 (dt, J = 3.32, 1.24 Hz, 2H), 4.14, (s, 2H), 3.68 (t, J = 6.8 Hz, 2H), 2.74 (t, J = 6.8 Hz, 2H), 1.37 (s, 9H). 13 C NMR (101 MHz, CDCl 3 ) δ (Cq), (Cq), (Cq), (CH), (Cq), (CH), (CH), (CH), (CH), (CH 2 ), (CH 2 ), (CH 2 ), (CH 2 ), (CH 2 ), (CH 2 ), (CH 2 ), (CH 3 ). RP-HPLC t R = min. N-(4-((tert-butoxycarbonyl)amino)butyl)-N-(o-nitrobenzenesoulfonyl) methyl glycinate (4h). Yellow oil (957 mg, quantitative); 1 H NMR (400 MHz, CDCl 3 ) δ (m, 1H), (m, 2H), (m, 1H), 4.55 (s, 1H), 4.17 (s, 2H), 3.66 (s, 1H), 3.41 (t, J = 7.2 Hz, 2H), 3.10 (q, J = 6.48 Hz, 2H), (m, 2H), (m, 11H). 13 C NMR (101 MHz, CDCl 3 ) δ (Cq), (Cq), S7

8 (Cq), (CH), (Cq), (CH), (CH), (CH), (CH 3 ), (CH 2 ), (CH 2 ), (CH 2 ), (CH 3 ), (CH 2 ), (CH 2 ). RP-HPLC t R = 9.22 min. Synthesis of tert-butyl 2-(2-((N-(2-methoxy-2-oxoethyl)-2-nitrophenyl)sulfonamido)ethyl)-1Hindole-1-carboxylate (4i) Compound 3i (286 mg, 0.68 mmol) was dissolved in THF and 4-dimethylamino pyridine (4 mg, mmol) and Boc 2 O (180 mg, 0.82 mmol) were added to the solution. The resulting mixture was stirred at 40 C and the reaction monitored by TLC (60% EtOAc in hexanes). Once the reaction completed, the solvent was removed under reduced pressure and the product purified by flash chromatography on silica gel (60% EtOAc in hexanes) to afford the desired compound as a yellow solid (320 mg, 91%); 1 H NMR (400 MHz, CDCl 3 ) δ 8.03 (d, J = 7.88 Hz, 1H), 7.87 (d, J = 7.88 Hz, 1H), (m, 2H), 7.45 (d, J = 7.6 Hz, 1H), 7.38 (t, J = 7.28 Hz, 1H), (m, 2H), 7.24 (m, 1H), 4.28 (s, 2H), (m, 5H), 2.96 (t, J = 7.28 Hz, 2H), 1.66 (s, 9H). 13 C NMR (101 MHz, CDCl 3 ) δ (Cq), (Cq), (Cq), (CH), (Cq), (CH), (CH), (Cq), (CH), (CH), (CH), (CH), (Cq), (CH), (Cq), (CH 3 ), (CH 2 ), (CH 3 ), (CH 2 ). RP-HPLC t R = min. Synthesis of methyl methyl (Z)-6-((tert-butoxycarbonyl)amino)-2,2-dimethyl-12-((2- nitrophenyl)sulfonyl)-4-oxo-3-oxa-5,7,12-triazatetradec-5-en-14-oate (4j) N-Substituted arylsulfonylglycine 4h (102mg, 0.23 mmol) was dissolved in TFA and the solution stirred for 1h at room temperature. The solvent was removed under reduced pressure and the TFA salt was precipitated in diethyl ether. The liquid suspension was removed and the product characterised and used in the next step. Brown gummy oil (105 mg, quantitative); 1 H NMR (400 MHz, CD 3 OD) δ (m, 1H), (m, 3H), 4.22 (s, 2H), 3.62 (s, 3H), (m, 2H), (m, 4H), 2.95 (t, J = 6.72 Hz, 2H), 1.70 (br s, 3H). 13 C NMR (101 MHz, CDCl 3 ) δ (Cq), (Cq), (CH), (Cq), (CH), (CH), (CH), (CH 2 ), (CH 3 ), (CH 2 ), (CH 2 ), (CH 2 ). RP-HPLC t R = 6.74 min. The TFA salt (105 mg, 0.23 mmol) was dissolved in anhydrous MeOH. Triethylamine (3 equiv.) and N,N -Di-Boc-1H-pyrazole-1-carboxamidine (1.5 equiv.) were added to the solution and the mixture stirred for 24 h at room temperature. Then MeOH was removed under reduced pressure and the product dissolved in EtOAc and washed with 0.1N HCl and brine. The organic layers were combined and the solvent removed under reduced pressure. The crude product was purified by flash chromatography on silica gel (Hexanes/EtOAc 1:1) to give the pure product as a colorless oil (85 mg, 66%). 1 H NMR (400 MHz, CDCl 3 ) δ (s, 1H), 8.28 (s, 1H), 8.08 (dd, J = 3.4, 2.4 Hz, 1H), 7.70 (m, 2H), (m, 1H), 4.18 (s, 2H), 3.66 (s, 3H), (m, 4H), (m, 22H). 13 C NMR (101 MHz, CDCl 3 ) δ (Cq), (Cq), (Cq), (Cq), (Cq), (CH), (Cq), (CH), (CH), (CH), (Cq), (Cq), (CH 3 ), (CH 2 ), (CH 2 ), (CH 2 ), (CH 3 ), (CH 3 ), (CH 2 ), (CH 2 ). RP-HPLC t R = min. S8

9 Synthesis of side chain protected N-substituted N-o-nitrobenzenesulfonylglycines (5a-f and 5h-j) N-Substituted glycine methyl ester (4a-f and h-j) was dissolved in THF (0.5M) and a solution of 1M LiOH/H 2 O (2 equiv) added to the mixture. The reaction was closely monitored by TLC 100% CH 2 Cl 2 and stopped upon completion. Then THF was removed under reduced pressure and the aqueous phase washed with EtOAc. The aqueous layer was then acidified with 0.1M HCl and extracted with EtOAc (3 ). The combined organic layers were dried over MgSO 4 and the solvent removed under reduced pressure to afford solid products. If necessary, the crude product was purified by flash chromatography (95/5 DCM/MeOH, 95/2.5/2.5 DCM/MeOH/AcOH). N-(3-(tert-butoxy)propyl)-N-(o-nitrobenzenesulfonyl )glycine (5a). White solid (106.0 mg, 90%); 1 H NMR (400 MHz, (CD 3 ) 2 CO) δ (m, 1H), (m, 3H), 4.26 (s, 2H), 3.54 (t, J = 7.24 Hz, 2H), 3.35 (t, J = 6.04 Hz, 2H), 1.77 (quint, J = 6.08 Hz, 2H), 1.12 (s, 9H). 13 C NMR (101 MHz, MeOD) δ (Cq), (Cq), (CH), (Cq), (CH), (CH), (CH), (Cq), (CH 2 ), (CH 2 ), (CH 2 ), (CH 3 ). HRMS (ESI-): Calcd for C 15 H 22 N 2 O 7 S [M-H] - : Da, found [M-H] - : Da. RP-HPLC t R = 8.83 min. (±) N-(2-(tert-butoxy)propyl)-N-(o-nitrobenzenesulfonyl) glycine (5b). White crystals (155.7 mg, 77%); 1 H NMR (400 MHz, (CD 3 ) 2 CO) δ (s, 1H), (m, 1H), (m, 3H), (m, 2H), (m, 1H), 3.32(m, 1H), 1.20 (t, J = 7.12 Hz, 1H), 1.16 (s, 9H), 1.07 (d, J = 6.2 Hz, 3H). 13 C NMR (101 MHz, (CD 3 ) 2 CO) δ (Cq), (Cq), (CH), (Cq), (CH), (CH), (CH), (Cq), (CH), (CH 2 ), (CH 2 ), (CH 3 ), (CH 3 ). HRMS (ESI-): Calcd for C 15 H 22 N 2 O 7 S [M-H] - : Da, found [M-H] - : Da. RP- HPLC t R = 9.18 min. (R)-N-(1-(tert-butoxy)propan-2-yl)-N-((o-nitrobenzenesulfonyl) glycine (5c). Pale yellow solid (72.1 mg, 83%); 1 H NMR (400 MHz, CDCl 3 ) δ 8.27 (dd, J = 6.4, 1.52 Hz, 1H), (m, 3H), 4.22 (dd, J = 43.12, 5.2 Hz, 2H), 4.12 (m, 1H), (m, 2H), 1.18 (d, J = 6.88 Hz, 3H), 1.06 (s, 9H). 13 C NMR (101 MHz, (CD 3 ) 2 CO) δ (Cq), (Cq), (CH), (Cq), (CH), (CH), (CH), (Cq), (CH 2 ), (CH), (CH 2 ), (CH 3 ), (CH 3 ). HRMS (ESI- ): Calcd for C 15 H 22 N 2 O 7 S [M-H] - : Da, found [M-H] - : Da. RP-HPLC t R = 9.34 min. N-(4-(tert-butoxy)phenethyl)-N-(o-nitrobenzenesulfonyl) glycine (5d). Pale yellow solid (151 mg, 86%); 1 H NMR (400 MHz, (CD 3 ) 2 CO) δ (m, 1H), (m, 3H), 7.11 (d, J = 8.36 Hz, 2H), 6.87 (d, J = 8.4 Hz, 2H), 4.21 (s, 2H), 3.64 (t, J = 7.8 Hz, 2H), 2.88 (t, J = 8.12 Hz, 2H), 1.28 (s, 9H). 13 C NMR (101 MHz, (CD 3 ) 2 CO) δ (Cq), (Cq), (Cq), (CH), (Cq), (CH), (CH), (CH), (CH), (CH), (Cq), (CH 2 ), (CH 2 ), (CH 2 ), (CH 3 ). HRMS (ESI-): Calcd for C 20 H 24 N 2 O 7 S [M-H] - : Da, found [M- H] - : Da. RP-HPLC t R = 9.99 min. N-((1R,2R)-2-(tert-butoxy)cyclopentyl)-N-(o-nitrobenzenesulfonyl) glycine (5e). Pale yellow solid (70.0 mg, 70%); 1 H NMR (400 MHz, (CD 3 ) 2 CO) δ (m, 1H), (m, 3H), 4.22 (m, 2H), (m, 2H), (m, 2H), (m, 3H), (m, 1H), 0.95 (s, 9H). 13 C NMR (101 MHz, (CD 3 ) 2 CO) δ (Cq), (Cq), (CH), (CH), (CH), (CH), (Cq), (CH), (CH), (CH 2 ), (CH 2 ), (CH 3 ), (CH 2 ), 20.48(CH 2 ). HRMS (ESI-): Calcd for C 17 H 24 N 2 O 7 S [M-H] - : Da, found [M-H] - : Da. RP-HPLC t R = 9.35 min. N-((1R,4R)-4-(tert-butoxy)cyclohexyl)-N-(o-nitrobenzenesulfonyl) glycine (5f). Brown solid (125.0 mg, 70%); 1 H NMR (400 MHz, (CD 3 ) 2 CO) δ (s, 1H), (m, 1H), (m, 3H), 4.16 (s, 2H), (m, 1H), (m, 1H), (m, 2H), (m, 4H), S9

10 (m, 2H), 1.12 (s, 9H). 13 C NMR (101 MHz, (CD 3 ) 2 CO) δ (Cq), (Cq) (CH), (Cq), (CH), (CH), (CH), (CH), (Cq), (CH), (CH), (CH 2 ), (CH 2 ), (CH 3 ). HRMS (ESI-): Calcd for C 18 H 26 N 2 O 7 S [M-H] - : Da, found [M- H] - : Da. RP-HPLC t R = 9.25 min. N-(4-((tert-butoxycarbonyl)amino)butyl)-N-(o-nitrobenzenesulfonyl) glycine (5h). White crystals (90.9, 92%); 1 H NMR (400 MHz, (CD 3 ) 2 CO) δ (s, 1H), 8.18 (dd, J = 6.04, 1.28, 1H), (m, 3H), 5.96 (s, 1H), 4.25 (s, 2H), 3.49 (t, J = 7.44 Hz, 2H), 3.05 (q, J = 6.72 Hz, 2H), (m, 2H), (m, 2H), 1.39 (s, 9H). 13 C NMR (101 MHz, (CD 3 ) 2 CO) δ (Cq), (Cq), (Cq), (CH), (Cq), , (CH), (CH), (CH), (Cq), (CH 2 ), (CH 2 ), (CH 2 ), (CH 3 ), (CH 2 ), (CH 2 ). HRMS (ESI-): Calcd for C 17 H 26 N 2 O 6 S [M-H] - : Da, found [M-H] - : Da. RP-HPLC t R = 8.91 min. N-(2-(1-(tert-butoxycarbonyl)-1H-indol-2-yl)ethyl)-N-(o-nitrobenzenesulfonyl) glycine (5i). Yellow solid (42.9 mg, 77%); 1 H NMR (400 MHz, (CD 3 ) 2 CO) δ 8.06 (d, J = 8.12 Hz, 1H), 7.96 (dd, J = 7,0, 1.08 Hz, 1H), (m, 2H), (m, 2H), 7.50 (s, 1H), (dt, J = 6.24, 1.12 Hz, 1H), (dt, J = 6.68, 1.08 Hz, 1H), 4.39 (s, 2H), 3.81 (t, J = 7.32 Hz, 2H), 3.08 (t, J = 7.32, 2H), 1.66 (s, 9H). 13 C NMR (101 MHz, (CD 3 ) 2 CO) δ (Cq), (Cq), (CH), (Cq), (CH), (CH), (CH), (CH), (CH), (CH), (CH), (Cq), (CH), (Cq), (CH 2 ), (CH 2 ), (CH 3 ), (CH 2 ). HRMS (ESI-): Calcd for C 23 H 25 N 3 O 8 S [M-H] - : Da, found [M-H] - : Da. RP-HPLC t R = min. (Z)-6-((tert-butoxycarbonyl)amino)-2,2-dimethyl-12-((2-nitrophenyl)sulfonyl)-4-oxo-3-oxa-5,7,12- triazatetradec-5-en-14-oic acid (5j). White solid (94.9 mg, 94%); 1 H NMR (400 MHz, (CD 3 ) 2 CO) δ 8.28 (br s, 1H), (m, 1H), (m, 3H), 4.27 (s, 2H), 3.53 (t, J = 7,0 Hz, 2H), (m, 2H), (m, 2H), (m, 2H), 1.52 (s, 9H), 1.44 (s, 9H). 13 C NMR (101 MHz, (CD 3 ) 2 CO) δ (Cq), (Cq), (Cq), (Cq), (Cq), (CH), (Cq), (CH), (CH), (CH), (Cq), (Cq), (CH 2 ), (CH 2 ), (CH 2 ), (CH 3 ), (CH 3 ), (CH 2 ), (CH 2 ). HRMS (ESI-): Calcd for C 23 H 35 N 5 O 10 S [M-H] - : Da, found [M-H] - : Da. RP-HPLC t R = 9.50 min. Synthesis of N-(3-(allyloxy)-3-oxopropyl)-N-((2-nitrobenzenesulfonyl) glycine (5g) N-Substituted glycine tert-butyl ester (4g) (214 mg, 0.50 mmol) was dissolved in a mixture of CH 2 Cl 2 and TFA (1:1). The mixture was stirred at room temperature and the reaction monitored by TLC (100% CH 2 Cl 2 ). Once the reaction completed, the solvent was removed under reduced pressure and the crude product used without further purification. White solid (188 mg, 99%); 1 H NMR (400 MHz, (CD 3 ) 2 CO) δ (m, 1H), (m, 3H), (m, 1H), (m, 1H), (m, 1H), (m, 2H), 4.32 (s, 2H), 3.75 (t, J = 7.08 Hz, 2H), 2.79 (t, J = 7.12 Hz, 2H). 13 C NMR (101 MHz, (CD 3 ) 2 CO) δ (Cq), (Cq), (Cq), (CH), (CH 2 ), (CH), (CH), (CH), (CH), (CH 2 ), (CH 2 ), (CH 2 ), (CH 2 ), (CH 2 ). HRMS (ESI-): Calcd for C 14 H 16 N 2 O 8 S [M-H] - : Da, found [M-H] - : Da. RP-HPLC t R = 8.51 min. S10

11 Synthesis of side chain amide derivatives (7a-c) tert-butyl 3-((N-(2-methoxy-2-oxoethyl)-o-nitrobenzene)sulfonamido)propanoate (6) tert-butyl 3-aminopropanoate (3.12 g, 17.2 mmol) was dissolved in CH 2 Cl 2 (1 M) followed by addition of Et 3 N (4.35 g, 43.0 mmol) and the resulting mixture was stirred at room temperature for 30 min. Then, a solution of o-nitrobenzenesulfonyl chloride (3.24 g, 14.6 mmol) in CH 2 Cl 2 (0.85 M) was added slowly and the reaction monitored by TLC (3% MeOH/ CH 2 Cl 2 ). When completed, the reaction was quenched with 0.1M HCl and aqueous phase extracted with CH 2 Cl 2 (3 30 ml). The combined organic layers were washed with brine and dried over MgSO 4. The solvent was removed under reduced pressure to afford the desired compound as a white powder (4.77 g, 99%). 1 H NMR (400 MHz, CDCl 3 ) δ (m, 1H), (m, 1H), (m, 1H), 5.97 (t, J = 5.84 Hz, 1H), 3.32 (q, J = 6.12 Hz, 2H), 2.50 (t, J = 6.12 Hz, 2H), 1.42 (s, 9H). 13 C NMR (101 MHz, CDCl 3 ) δ (Cq), (Cq), (Cq), (CH), (CH), (CH), (CH), (Cq), (CH 2 ), (CH 2 ), (CH 3 ). RP- HPLC t R = 9.54 min. tert-butyl 3-((o-nitrobenzene)sulfonamido)propanoate (3.98 g, 12.0 mmol) was dissolved in anhydrous DMF (0.1 M) in presence of K 2 CO 3 (3.32 g, 24.0 mmol) under argon. The mixture was stirred for 15 minutes before the addition of methyl bromoacetate (2.75 g, 18.0 mmol). The solution was stirred for 3 h at room temperature and quenched with the addition of water. The aqueous phase was extracted with CH 2 Cl 2 (3 ) and the combined organic layers with water (2 ), 5% NaHCO 3 (2 ) and brine (2 ). The organic layer was dried over MgSO 4 and the solvent removed under reduced pressure. The desired product (6) was obtained as a yellow oil (4.75 g, 98%) and used without further purification in the next step. 1 H NMR (400 MHz, CDCl 3 ) δ (m, 1H), (m, 2H), (m, 1H), 4.26 (s, 2H), (m, 5H), 2.61 (t, J = 6.76 Hz, 2H), 1.42 (s, 9H). 13 C NMR (101 MHz, CDCl 3 ) δ (Cq), (Cq), (Cq), (CH), (Cq), (CH), (CH), (CH), (Cq), (CH 3 ), (CH 2 ), (CH 2 ), (CH 2 ), (CH 3 ). RP-HPLC t R = min. Synthesis of side chain amides derivative from tert-butyl 3-((N-(2-methoxy-2-oxoethyl)-onitrobenzene)sulfonamido)propanoate (7a-c) tert-butyl 3-((N-(2-methoxy-2-oxoethyl)-o-nitrobenzene)sulfonamido)propanoate (6) (1.22 g, 2.98 mmol) was dissolved in a solution of 50% TFA in CH 2 Cl 2. The solution was stirred at room temperature and monitored by TLC (100% CH 2 Cl 2 ). Once the reaction is complete, the solvent was removed under reduced pressure and the crude product obtained was used without further purifications. Yellowish powder (1.02g, 97%); 1 H NMR (400 MHz, (CD 3 ) 2 SO) δ (s, 1H), 8.10 (dd, J = 6.24, 1.4 Hz, 1H), 7.96 (dd, J = 6.36, 1.44 Hz, 1H), (m, 2H), 4.25 (s, 2H), 3.57 (s, 3H), 3.53 (t, J = 7.28 Hz, 2H), 2.56 (t, J = 7.32 Hz, 2H). 13 C NMR (101 MHz, (CD 3 ) 2 SO) (Cq), (Cq), (Cq), (CH), (CH), (Cq), (CH), (CH), (CH 3 ), (CH 2 ), (CH 2 ), (CH 2 ). RP- HPLC t R = 7.60 min. The acid compound was dissolved in CH 2 Cl 2 (10 ml/mmol) in presence of the appropriate amine (2 equiv.) and the resulting solution cooled at 0 C. Then 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (2 equiv) and 4-dimethylaminopyridine (0.05 equiv) were added to the mixture. After stirring for 6 h at room temperature, the solution was washed with 0.1N HCl (3 ), 5% NaHCO 3 (3 ) and S11

12 brine (1 ). The organic layer was dried over MgSO 4, the solvent removed under reduced pressure to afford the desired compounds as white powders solids in moderate to excellent yields. Methyl N-((2-nitrophenyl)sulfonyl)-N-(3-oxo-3-(piperidin-1-yl)propyl)glycinate. White solid (133 mg, 73%); 1 H NMR (400 MHz, (CDCl 3 ) δ (m, 1H), (m, 2H), (m, 1H), 4.30 (s, 2H), 3.66 (t, J = 6.6 Hz, 2H), 3.62 (s, 3H), 3.49 (t, J = 5.6 Hz, 2H), 3.36 (t, J = 5.6 Hz, 2H), 2.74 (t, J = 6.56 Hz, 2H), (m, 6H). 13 C NMR (101 MHz, CDCl 3 ) δ (Cq), (Cq), (CH), (Cq), (CH), (CH), (CH), (CH 3 ), (CH 2 ), (CH 2 ), (CH 2 ), (CH 2 ), (CH 2 ), (CH 2 ), (CH 2 ), (CH 2 ). ). RP-HPLC t R = 8.95 min. Methyl N-(3-(diethylamino)-3-oxopropyl)-N-((2-nitrophenyl)sulfonyl)glycinate. White solid (108 mg, 61%); 1 H NMR (400 MHz, (CDCl 3 ) δ (m, 1H), (m, 2H), (m, 1H), 4.32 (s, 2H), 3.69 (t, J = 6.44 Hz, 2H), 3.62 (s, 3H), (m, 4H), 2.75 (t, J = 6.36 Hz, 2H), 1.17 (t, J = 7.12 Hz, 3H), 1.10 (t, J = 7.08 Hz, 3H). 13 C NMR (101 MHz, CDCl 3 ) δ (Cq), (CH), (Cq), (CH), (CH), (CH), (CH 3 ), (CH 2 ), (CH 2 ), (CH 2 ), (CH 2 ), (CH 2 ), (CH 3 ), (CH 3 ). RP-HPLC t R = 8.77 min. Methyl N-((2-nitrophenyl)sulfonyl)-N-(3-oxo-3-(phenylamino)propyl)glycinate. White solid (971 mg, 82%); 1 H NMR (400 MHz, (CDCl 3 ) δ (m, 1H), 7.73 (s, 1H), (m, 2H), (m, 2H), 7.47 (d, J = 7.88 Hz, 2H), 7.30 (t, J = 7.68 Hz, 2H), 7.11 (t, J = 7.4 Hz, 1H), 4.30 (s, 2H), 3.77 (t, J = 5.96 Hz, 2H), 3.66 (s, 3H), 2.76 (t, J = 6.36 Hz, 2H). 13 C NMR (101 MHz, CDCl 3 ) δ (Cq), (CH), (CH), (CH), (CH), (CH), (CH), (CH), (CH 3 ), (CH 2 ), (CH 2 ), (CH 2 ). RP-HPLC t R = 9.24 min. N-Substituted glycine methyl ester was dissolved in THF (0.5M) and a solution of 1M LiOH/H 2 O (2 equiv) added to the mixture. The reaction was closely monitored by TLC 100% CH 2 Cl 2 and stopped when only the desired product was seen. Then THF was removed under reduced pressure and the aqueous phase washed with EtOAc. The aqueous layer was acidified with 0.1M HCl and extracted with EtOAc (3 ). The combined organic layers were dried over MgSO 4 and the solvent removed under reduced pressure to afford solid products that can be used without further purifications. N-((2-nitrophenyl)sulfonyl)-N-(3-oxo-3-(piperidin-1-yl)propyl)glycine (7a). White powder (486.3 mg, 90%); 1 H NMR (400 MHz, (CD 3 ) 2 CO) δ (s, 1H), (m, 1H), (m, 3H), 4.34 (s, 2H), 3.71 (t, J = 6.84 Hz, 2H), 3.47 (t, J = 5.56 Hz, 2H), 3.41 (t, J = 5.48 Hz, 2H), 2.75 (t, J = 6.84 Hz, 2H), (m, 2H), (m, 2H), (m, 2H). 13 C NMR (101 MHz, (CD 3 ) 2 CO) δ (Cq), (Cq), (Cq), (CH), (Cq), (CH), (CH), (CH), (CH 2 ), (CH 2 ), (CH 2 ), (CH 2 ), (CH 2 ), (CH 2 ), (CH 2 ), (CH 2 ). HRMS (ESI-): Calcd for C 16 H 21 N 3 O 7 S [M-H] - : Da, found [M-H] - : Da. RP- HPLC t R = 8.12 min N-(3-(diethylamino)-3-oxopropyl)-N-((2-nitrophenyl)sulfonyl)glycine (7b). White powder (484.1 mg, 91%); 1 H NMR (400 MHz, (CD 3 ) 2 CO) δ (m, 1H), (m, 3H), 4.34 (s, 2H), 3.73 (t, J = 6.76 Hz, 2H), (m, 4H), 2.75 (t, J = 6.72 Hz, 2H), (m, 3H), (m, 3H). 13 C NMR (101 MHz, (CD 3 ) 2 CO) δ (Cq), (Cq), (Cq), (CH), (Cq), (CH), (CH), (CH), (CH 2 ), (CH 2 ), (CH 2 ), (CH 2 ), (CH 2 ), (CH 3 ), (CH 3 ). HRMS (ESI-): Calcd for C 15 H 21 N 3 O 7 S [M-H] - : Da, found [M- H] - : Da. RP-HPLC t R = 7.94 min N-((2-nitrophenyl)sulfonyl)-N-(3-oxo-3-(phenylamino)propyl)glycine (7c). White powder (58 mg, 59%); 1 H NMR (400 MHz, (CD 3 ) 2 CO) δ 9.30 (s, 1H), (m, 1H), (m, 3H), 7.60 (d, J = 7.64 Hz, 2H), 7.28 (t, J = 7.52 Hz, 2H), (m, 1H), 4.35 (s, 2H), 3.81 (t, J = 6.8 Hz, 2H), 2.79 ( t, J = 6.8 Hz, 2H). 13 C NMR (101 MHz, (CD 3 ) 2 CO) δ (Cq), 169,67 (Cq), (Cq), (Cq), S12

13 (CH), (Cq), (CH), (CH), (CH), (CH), (CH), (CH), (CH 2 ), (CH 2 ), (CH 2 ). HRMS (ESI-): Calcd for C 17 H 17 N 3 O 7 S [M-H] - : Da, found [M-H] - : Da. RP-HPLC t R = 8.38 min. Peptoid and Peptomer synthesis The synthesis of peptoid oligomers 8-11 was performed on Rink amide resin ( 50 mg, 0.56 mmol/g) by standard submonomer or monomer method. Submonomer approach Acylation step: Resin-bound free primary or secondary amines were treated with a mixture of 1.2 M bromoacetic acid in DMF (0.8 ml) and DIC (0.2 ml, 1.27 mmol) for 40 min. The resin was filtered and washed with DMF (5 30 s). Amination step: Resin-bound bromoacetylated oligomers were treated with a solution of 1 M primary amine in DMF (1 ml) for 40 min. The resin was filtered and washed with DMF (5 30 s). These 2 steps were repeated until the desired oligomer was obtained. When the synthesis was completed the resin was washed with DMF (5 30 s) and CH 2 Cl 2 (5 30 s) and dried under vacuum. Insertion of monomers or amino acids on peptoids (8-11) A Fmoc-amino acid or ons-nsg monomer (5a-j or 7a-c) (3 equiv.) was added to a mixture of HATU (3 equiv.) and HOAt (3 equiv.). NMM (6 equiv.) was then added to the mixture and the resulting solution introduced into a syringe containing the elongating oligomer on solid support. The mixture was stirred for 3 h and the evolution of the reaction monitored using the chloranil test. Fmoc group removal The Fmoc protecting group was removed by treating the resin twice with a solution of 20% piperidine in DMF (v/v) for 10 min followed by washing with DMF (5 30 s). ons group cleavage The resin bearing ons-protected oligomers was treated with a solution of p-methoxybenzenethiol (15 equiv) and DBU (20 equiv) in DMF (1 ml) for 10 min at room temperature. The step was repeated and the resin washed with DMF (5 30 s). Cleavage of peptoid and peptomer oligomers from the resin The resin bearing the peptoid oligomers was treated with a cleavage solution composed of TFA/water/TIS (95:2.5:2.5) for 1 h. After filtration the resin was washed with CH 2 Cl 2 (5 ) and the filtrate was evaporated to dryness under reduced pressure. The crude products were precipitated in cold Et 2 O and centrifuged. The supernatant was carefully discarded and this process repeated twice. The residue was dried under vacuum and submitted to HPLC, HRMS and MS/MS analyses. Allyl ester deprotection The resin was swollen in CH 2 Cl 2 for 15 minutes before the introduction of a mixture of Pd(PPh 3 ) 4 (0.5 equiv) and phenylsilane (15 equiv) in CH 2 Cl 2 and stirred for 40 minutes. The step was repeated once and the resin washed with CH 2 Cl 2 (3 30 s), with a solution of 0.5% DIPEA in DMF (3 30 s), with a solution of 0.5% sodium diethyldithiocarbamate trihydrate in DMF (3 30s) and another time with CH 2 Cl 2 (3 30 s). Peptoids cyclisation The resin bearing the free carboxylic acid and the free N-terminus amine was swollen in DMF for 15 min. Then a solution of PyAOP (5 equiv), HOAt (5 equiv), and DIPEA (10 equiv) in DMF was added to the resin and the resulting mixture was stirred for 6 h. Finally, the resin was washed with DMF (5 30 s). S13

14 HPLC purification Compounds 8-11 were purified by RP-HPLC on a Vydac 218MS C18 column (22.0 x 250 mm, 300 Å, 10 µm) using 0.1% TFA/H 2 O (A) and 0.1% TFA/CH 3 CN (B), with a linear gradient of 10% to 100% of B for 20 min at 10 ml min -1 and UV detection at 220 nm and 254 nm. The collected fractions were freeze dried to afford the desired peptoid oligomers as white powder. Sequence Table S1. Sequence, characterization data and yields for peptoid oligomers 8-11 RP-HPLC t R (min) 8a b c d e f g h i j k l m HRMS (ESI) m/z Calculated (Da) C 30 H 51 N 7 O C 30 H 51 N 7 O C 30 H 51 N 7 O C 35 H 53 N 7 O C 32 H 53 N 7 O C 33 H 55 N 7 O C 30 H 49 N 7 O C 31 H 54 N 8 O C 37 H 54 N 8 O C 32 H 56 N 10 O C 35 H 58 N 8 O C 34 H 58 N 8 O C 36 H 54 N 8 O C 30 H 47 N 7 O C 47 H 70 N 10 O C 40 H 59 N 9 O Observed (Da) a Yields based on initial loading of Rink Amide AM resin (0.56 mmol/g). Crude purity (%) Purified mass (mg) Purified yields (%) a S14

15 Table S2. Sequence fragments observed by MS-MS from peptoid oligomers in Da Cmpd Y 1 Y 2 Y 3 Y 4 Calculated Observed Calculated Observed Calculated Observed Calculated Observed 8a b c d e f g h i j k l m Cmpd b 1 b 2 b 3 b 4 Calculated Observed Calculated Observed Calculated Observed Calculated Observed 8a b c d e f g h i j k l m S15

16 Figure S1. HPLC traces (λ = 220 nm) and MS (ESI-) of the final ons-nsg monomers (5a-j) 5a 5b S16

17 Figure S1. (continued) 5c 5d S17

18 Figure S1. (continued) 5e 5f S18

19 Figure S1. (continued) 5g 5h S19

20 Figure S1. (continued) 5i 5j S20

21 Figure S1. (continued) 7a 7b S21

22 Figure S1. (continued) 7c S22

23 Figure S2. 1 H NMR and 13 C NMR spectra of the final monomers (5a-j) S23

24 Figure S2. (continued) S24

25 Figure S2. (continued) S25

26 Figure S2. (continued) S26

27 Figure S2. (continued) S27

28 Figure S2. (continued) S28

29 Figure S2. (continued) S29

30 Figure S2. (continued) S30

31 Figure S2. (continued) S31

32 Figure S2. (continued) S32

33 Figure S3. LC-MS/MS characterization for peptoid (8a-m, 9-11) HPLC 2800 Intensity (mau) Time (min) 8a MS [M+2H] 2+ /2 MS MS b y b2 y2 b3 y3 b y4 HPLC 2800 Intensity (mau) Time (min) 8b MS [M+2H] 2+ / MS MS b y b2 y3 y2 b b y4 S33

34 Figure S3. (continued) HPLC 2800 Intensity (mau) Time (min) 8c MS [M+2H] 2+ /2 MS MS b y b2 y3 y2 b b y HPLC Intensity (mau) Time (min) 8d MS [M+2H] 2+ /2 MS MS b1 y b b y2 y3 b y S34

35 Figure S3. (continued) HPLC Intensity (mau) e Time (min) MS [M+2H] 2+ /2 MS MS b1 y b2 b y2 y3 b y4 HPLC 2800 Intenity (mau) f Time (min) MS [M+2H] 2+ /2 MS MS b y b y2 b3 y3 b4 501,3093 y4 S35

36 Figure S3. (continued) HPLC Intensity (mau) g Time (min) MS MS MS y1 b2 y2 y b b b y4 HPLC 2800 Intensity (mau) Time (min) 8h MS [M+2H] 2+ /2 MS MS b2 b y b b y3 y2 y4 S36