1,2-Dichloroethane → 4-bromo-7-(4-methylpiperazine-1-carbonyl)-9H-carbazole-1-carboxamide

Participants

Reaction Steps

A suspension of 5-bromo-8-carbamoyl-9H-carbazole-2-carboxylic acid (Intermediate 49-1, 1.84 g, 4.97 mmol), EDC (1.334 g, 6.96 mmol), and HOBT (1.066 g, 6.96 mmol) in THF-DCM-DMF (4:1:1) (124 mL) was treated with 1-methylpiperazine (1.656 mL, 14.91 mmol) and the mixture was stirred at rt for 3 days. The mixture was concentrated and the residue was partitioned between DCM and NaHCO3 (aq). The organic phase was washed with brine, dried and concentrated to afford an oil. This was purified by column chromatography (DCM-2 M methanolic ammonia, 100:0 to 95:5 to 92.5:7.5). The resulting solid was suspended in EtOAc, collected by filtration and dried to provide 4-bromo-7-(4-methylpiperazine-1-carbonyl)-9H-carbazole-1-carboxamide (1.57 g, 76%). 1H NMR (400 MHz, DMSO-d6) δ 11.83 (s, 1H) 8.57 (d, J=8.13 Hz, 1H) 8.20 (br. s., 1H) 7.84 (d, J=8.35 Hz, 1H) 7.79 (s, 1H) 7.56 (br. s., 1H) 7.42 (d, J=8.13 Hz, 1H) 7.22 (d, J=8.13 Hz, 1H) 3.30-3.70 (m, 4H) 2.19-2.39 (m, 4H) 2.16 (s, 3H). Mass spectrum m/z 415, 417 (M+H)+.

Provenance & Evidence