Phosphorus oxychloride → ethyl 5-bromo-8-cyano-9H-carbazole-2-carboxylate

Participants

Reaction Conditions

Reaction Steps

Step 1 A suspension of ethyl 5-bromo-8-carbamoyl-9H-carbazole-2-carboxylate (Intermediate 48-1, 2.2 g, 6.09 mmol) in phosphorus oxychloride (45.4 mL, 487 mmol) was heated at 105° C. for 1 h. The suspension was cooled to rt and concentrated to give a brown solid, which was suspended in water. The precipitate was collected by filtration, washed with water and dried to provide ethyl 5-bromo-8-cyano-9H-carbazole-2-carboxylate (2.05 g, 98%) as light brown solid. 1H NMR (400 MHz, DMSO-d6) δ 12.78 (s, 1H) 8.71 (d, J=8.57 Hz, 1H) 8.24 (s, 1H) 7.95 (d, J=8.57 Hz, 1H) 7.89 (d, J=8.13 Hz, 1H) 7.61 (d, J=8.13 Hz, 1H) 4.39 (q, J=7.10 Hz, 2H) 1.37 (t, 2H). Mass spectrum m/z 360, 362 (M+NH4)+.

Provenance & Evidence