A mixture of 4-(3-(3,4-dimethyl-2-oxo-2,5-dihydro-1H-pyrrol-1-yl)-2-methylphenyl)-7-(2-hydroxypropan-2-yl)-9H-carbazole-1-carboxamide (Example 81-21, 20 mg, 0.043 mmol) and ammonium formate (27.0 mg, 0.428 mmol) in methanol (5 mL) was treated with 10% palladium on charcoal (20 mg, 0.019 mmol). The mixture was stirred under nitrogen at rt for 2 h. Additional ammonium formate (27.0 mg, 0.428 mmol) was added and the mixture was stirred at rt overnight. More ammonium formate (57 mg) and 10% palladium on charcoal (40 mg) were added, and after 6 h more additional ammonium formate (57 mg) was added. The mixture was again stirred overnight, then was diluted with DCM and filtered through Celite. The filtrate was washed with water, dried and concentrated. The residue was purified by preparative HPLC and the appropriate effluent fractions were made basic with 1 M aqueous sodium hydroxide and extracted twice with DCM. The combined organic phases were washed with water, dried and concentrated to provide 4-(3-(3,4-dimethyl-2-oxopyrrolidin-1-yl)-2-methylphenyl)-7-(2-hydroxypropan-2-yl)-9H-carbazole-1-carboxamide as a white solid (11 mg, 55%), which was a mixture of diastereomers. Mass spectrum m/z 452.1 (M+H—H2O)+.
