(3S)-3-{[N-(1H-Benzimidazol-2-ylcarbonyl)-l-leucyl]amino}-2-oxo-4-[(3S)-2-oxopyrrolidin-3-yl]butyl 2,6-Dichlorobenzoate (31)
Following the procedure described for the preparation of N-((1S)-1-{[((1S)-3-chloro-2-oxo-1-{[(3S)-2-oxopyrrolidin-3-yl]methyl}propyl)amino]carbonyl}-3-methylbutyl)-4-methoxy-1H-indole-2-carboxamide but substituting (3S)-3-{[N-(tert-butoxycarbonyl)-l-leucyl]amino}-2-oxo-4-[(3S)-2-oxopyrrolidin-3-yl]butyl 2,6-dichlorobenzoate and 1H-benzimidazole-2-carboxylic acid and making noncritical variations provided a crude yellow oil. This material was purified by Biotage MPLC (25 M, 3–4% methanol/dichloromethane) to afford 95 mg (72%) of the title compound as an off-white foam. 1H NMR (DMSO-d6) δ 13.32 (s, 1H), 8.89 (d, J = 8 Hz, 1H), 8.60 (d, J = 8 Hz, 1H), 7.74 (d, J = 8 Hz, 1H), 7.59 (m, 5H), 7.29 (m, 2H), 5.20 (d, J = 20 Hz, 1H), 5.15 (d, J = 20 Hz, 1H), 4.56 (m, 2H), 3.12 (m, 2H), 2.30 (m, 1H), 2.01 (m, 2H), 1.83 (m, 1H), 1.65 (m, 4H), 0.92 (d, J = 8 Hz, 3H), 0.89 (d, J = 8 Hz, 3H); MS (ESI+) for C29H31Cl2N5O6m/z 616.0 (M + H)+. Anal. calcd for C29H31Cl2N5O6: C, 56.50; H, 5.07; N, 11.36. Found: C, 57.28; H, 5.32; N, 11.35. HRMS (ESI+) calcd for C29H31Cl2N5O6+H1 616.1724, found 616.1729.