N-bromobutanimide → Ethyl 6-bromo-2-aminobenzo[b]thiophene-3-carboxylate

Participants

Reaction Steps

Ethyl 2-amino-1-benzothiophene-3-carboxylate (10.4 g, 44.7 mmol) was dissolved in chloroform (100 mL) and treated with NBS (7.95 g, 44.7 mmol). Upon completion of the reaction, a light tan solid precipitated from the mixture. The slurry was concentrated to ˜30% of the original volume on a rotavap and then filtered. The solid was slurried in EtOAc (300 mL) and treated with satd NaHCO3 (200 mL) to obtain two clear phases. The organic phase was washed further with satd NaHCO3 (4X˜200 mL) and water (200 mL). The organic layer was collected, dried with sodium sulfate, filtered, and concentrated to yield an off-white solid (9.1 g, 68%). 1H NMR (DMSO-d6) δ 8.00 (s, 2H), 7.85 (s, 1H), 7.83 (d, 1H), 7.36 (d, 1H), 4.28 (q, 2H), 1.33 (t, 3H).

Provenance & Evidence