Reaction Steps
DMAP (89 mg, 0.73 mmol), p-anisidine (0.10 g, 0.81 mmol) and DIC (0.13 mL, 0.81 mmol) were added to the solution of crude [3-(tert-butoxycarbonyl)-9,10-dichloro-2,3,4,5-tetrahydroazepino[4,5-b]indol-6(1H)-yl]acetic acid (0.30 g, 0.73 mmol) in dry THF (3.5 mL). After 4 h, additional p-anisidine (45 mg, 0.37 mmol) was added. The reaction was diluted with EtOAc after another 17 h and washed with 10% aqueous citric acid (20 mL), saturated aqueous NaHCO3 (20 mL), and brine (20 mL). The organic layer was then dried over Na2SO4, decanted, and concentrated impure product. It was then crystallized from EtOAc/heptane, triturated with pentane, and recrystallized from EtOAc/heptane to give 0.14 g (36%) of a white solid: mp 143.0-144.0° C.; 1H NMR (300 MHz, DMSO) δ 10.30 (s, 1H), 7.47 (m, 3H), 7.25 (d, J 8.7 Hz, 1H), 6.88 (d, J=9.0 Hz, 2H), 5.04 (br s, 2H), 3.71 (s, 3H), 3.63 (m, 4H), 3.39 (m, 2H), 2.99 (m, 2H), 1.40 (app d, 9H); IR (diffuse reflectance) 2975, 1666, 1545, 1514, 1474, 1451, 1414, 1365, 1253, 1239, 1222, 1173, 1158, 830, 784 cm1; MS (EI) m/z 517 (M+), 377, 375, 227, 224, 212, 134, 124, 121, 55, 53; MS (FAB) m/z 518 (M+H+), 520, 519, 518, 517, 464, 463, 462, 461, 418, 57; HRMS (EI) calcd for C26H29Cl2N3O4 517.1535, found 517.1537; Anal. Calcd for C26H29Cl2N3O4: C, 60.24; H, 5.64; N, 8.10; found: C, 59.86; H, 5.68; N, 7.94.
