p-Toluenesulfonic acid → di(tert-butyl) 2-[({1-(chloromethyl)-5-nitro-3-(5,6,7-trimethoxyindol-2-carbonyl)-1,2-dihydro-3H-benzo[e]indol-7-yl}sulfonyl)amino]ethyl phosphate

Participants

Reaction Steps

A mixture of 227 (77 mg, 0.13 mmol), 5,6,7-trimethoxyindole-2-carboxylic acid (44 mg, 0.17 mmol), EDCI (102 mg, 0.52 mmol), and TsOH (5 mg, 0.03 mmol) in DMA (1.5 mL) was stirred at room temperature for 2 h. Ice-cold aqueous NaHCO3 was added and the mixture was extracted with EtOAc (×2). The combined extracts were washed with brine (×2), dried, and the solution was evaporated onto silica Chromatography, eluting with EtOAc/petroleum ether (3:2 then 4:1 then EtOAc alone) gave di(tert-butyl) 2-[({1-(chloromethyl)-5-nitro-3-(5,6,7-trimethoxyindol-2-carbonyl)-1,2-dihydro-3H-benzo[e]indol-7-yl}sulfonyl)amino]ethyl phosphate (228) (71 mg, 66%) as a yellow solid. A sample was triturated with CH2Cl2: mp 231-236° C. (dec.); 1H NMR [(CD3)2SO] δ 11.60 (d, J=1.6 Hz, 1H), 9.24 (s, 1H, 8.87 (d, J=1.7 Hz, 1H), 8.44 (d, J=8.9 Hz, 1H), 8.15 (br s, 1H), 8.01 (dd, J=8.9, 1.8 Hz, 1H), 7.20 (d, J=2.1 Hz, 1H), 6.98 (s, 1H), 4.96-4.90 (m, 1H), 4.68-4.59 (m, 2H), 4.18-4.07 (m, 2H), 3.95 (s, 3H), 3.87-3.82 (ni 2H), 3.84 (s, 3H), 3.81 (s, 3H), 3.10-3.04 (m, 2H), 1.36 (s, 18H). Anal, (C35H44ClN4O12PS) C, H, N.

Provenance & Evidence