N-((1S)-1-{[((1S)-3-Chloro-2-oxo-1-{[(3S)-2-oxopyrrolidin-3-yl]methyl}propyl)amino]carbonyl}-3,3-dimethylbutyl)-1H-indole-2-carboxamide
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 N2-(tert-butoxycarbonyl)-N1-((1S)-3-chloro-2-oxo-1-{[(3S)-2-oxopyrrolidin-3-yl]methyl}propyl)-4-methyl-l-leucinamide and indole-2-carboxylic acid and making no other critical variations provided a crude yellow foam. This material was purified by Biotage MPLC (40 M column, 2.5–3.5% methanol/chloroform) to afford 1.06 g (62%) of the title compound as a light yellow foam. 1H NMR (DMSO-d6) δ 11.59 (s, 1H), 8.58 (d, J = 8 Hz, 1H), 8.50 (d, J = 8 Hz, 1H), 7.64 (s, 1H), 7.61 (d, J = 8 Hz, 1H), 7.41 (d, J = 8 Hz, 1H), 7.23 (s, 1H), 7.17 (t, J = 8 Hz, 1H), 7.02 (t, J = 8 Hz, 1H), 4.62–4.50 (m, 3H), 4.45 (m, 1H), 3.10 (m, 2H), 2.25 (m, 1H), 2.08 (m, 1H), 1.96 (m, 1H), 1.80 (m, 1H), 1.72–1.58 (m, 3H), 0.94 (s, 9H); MS (ESI+) for C24H31ClN4O4m/z 475.1 (M + H)+; anal. calcd for C24H31ClN4O4·0.35 CHCl3: C, 56.59; H, 6.12; N, 10.84. Found: C, 56.38; H, 6.18; N, 10.75; HRMS (ESI+) calcd for C24H31ClN4O4 475.2107, found 475.2122.