Water → 4-bromo-3-chloro-7-(2-hydroxypropan-2-yl)-9H-carbazole-1-carboxamide

Participants

Reaction Conditions

Reaction Steps

A solution of ethyl 5-bromo-8-carbamoyl-6-chloro-9H-carbazole-2-carboxylate (4.14 g, 10.5 mmol) in THF (200 mL) cooled in a dry ice-acetone bath was treated portionwise over 30 min with 1.6 M methyllithium in hexanes (45.8 mL, 73.2 mmol). The mixture was stirred at −78° C. for 60 min, then was treated portionwise with saturated aqueous NH4Cl. Water was added and the mixture was extracted twice with EtOAc. The combined organic phases were washed twice with water. All aqueous phases were combined and extracted with DCM, and this organic phase was washed with water. All organic phases were combined, dried and concentrated. The residue was crystallized from EtOAc to give a solid. The residue from concentration of the mother liquor was purified by chromatography on silica gel (330 g), eluting with EtOAc-hexanes (gradient from 0-100%), to give additional solid. The two solids were combined to give 4-bromo-3-chloro-7-(2-hydroxypropan-2-yl)-9H-carbazole-1-carboxamide as a light yellow solid (3.13 g, 78% yield). Mass spectrum m/z 363, 365, (M+H—H2O)+. 1H NMR (400 MHz, DMSO-d6) δ 11.71 (s, 1H), 8.56 (d, J=8.6 Hz, 1H), 8.29 (br. s., 1H), 8.17 (s, 1H), 7.97 (d, J=1.3 Hz, 1H), 7.66 (br. s., 1H), 7.42 (dd, J=8.6, 1.8 Hz, 1H), 1.52 (s, 6H).

Provenance & Evidence