Reaction Steps
Dichlorotriphenylphosphorane (1.65 g, 5.1 mmol) was added to a solution of 56 (1.34 g, 2.55 mmol) in pyridine (75 mL) and the solution stirred at 20° C. After 10 min more dichlorotriphenylphosphorane (2.06 g, 6.4 mmol) was added, and after a further 10 min the solution was poured into H2O and the mixture stirred for 5 min. The precipitated solid was filtered off, washed with H2O, and redissolved in CH2Cl2 (400 mL). This solution was filtered through Celite, eluting with CH2Cl2, and the filtrate was dried (Na2SO4) and evaporated. The resulting orange solid was recrystallized from CH2Cl2 giving methyl 1-(chloromethyl)-5-nitro-3-[(5,6,7-trimethoxyindol-2-yl)carbonyl]-1,2-dihydro-3H-pyrrolo[3,2-e]indole-7-carboxylate (31) as an orange powder (0.88 g, 64%), mp 246-247.5° C. The mother liquor was evaporated onto silica and purified by chromatography (50% EtOAc-petroleum ether) to give further 31 (0.50 g, 36%). 1H NMR (CDCl3) δ 10.39 (s, 1 H, NH), 9.42 (s, 1 H, NH), 9.39 (s, 1 H, H-4), 7.31 (d, J=2.2 Hz, 1 H, H-8), 6.97 (d, J=2.4 Hz, 1 H, H-3'), 6.86 (s, 1 H, H-4'), 4.80 (t, J=10.0 Hz, 1 H, H-2), 4.69 (dd, J=10.8, 4.4 Hz, 1 H, H-2), 4.32-42.3 (m, 1 H, H-1). 4.09 (s, 3 H, OMe), 4.05 (dd, J=11.4, 3.9 Hz, 1 H, CH2Cl), 4.02 (s, 3 H, OMe), 3.95 (s, 3 H, OMe), 3.91 (s, 3 H, OMe), 3.77 (dd, J=11.4, 8.8 Hz, 1 H, CH2Cl); 13C NMR [(CD3)2SO] δ 160.5, 160.0, 149.2, 140.0, 139.0, 137.5, 133.6, 132.1, 131.3, 130.2, 127.7, 126.1, 125.5, 123.2, 111.3, 107.5, 106.4, 97.9, 61.1, 60.9, 55.9, 54.1, 52.3, 47.0, 42.0. Anal. Calculated for C25H23ClN4O8 : C, 55.3; H, 4.3; N, 10.3. Found: C, 55.4; H, 4.1; N, 10.3%.
