ethyl 5-bromo-8-carbamoyl-9H-carbazole-2-carboxylate → 4-bromo-7-(1-hydroxycyclopropyl)-9H-carbazole-1-carboxamide

Participants

Reaction Steps

Step 1 A solution of ethyl 5-bromo-8-carbamoyl-9H-carbazole-2-carboxylate (Intermediate 48-1, 0.275 g, 0.761 mmol) was treated with titanium (IV) isopropoxide (0.31 mL, 1.07 mmol), followed by ethylmagnesium chloride (2 M in THF, 3.81 mL, 7.61 mmol). The mixture was stirred at rt for 1 h, then was cooled on ice and treated with water (10 mL). After 30 min, the solid was removed by filtration and rinsed with ether (150 mL). The organic layer was dried and concentrated to give 4-bromo-7-(1-hydroxycyclopropyl)-9H-carbazole-1-carboxamide as a yellow solid (0.220 g, 79%). 1H NMR (400 MHz, DMSO-d6) δ 11.65 (1 H, s), 8.52 (1 H, d, J=8.4 Hz), 8.25 (1 H, br. s.), 7.84-7.89 (2 H, m), 7.61 (1 H, br. s.), 7.45 (1 H, d, J=8.1 Hz), 7.13 (1 H, dd, J=8.5, 1.7 Hz), 6.11 (1 H, s), 1.21-1.27 (2 H, m), 1.06-1.11 (2 H, m).

Provenance & Evidence