N-bromobutanimide → 2-Bromo-5-fluoro-3-methylbenzo[b]thiophene

Participants

Reaction Steps

A 3 neck 2 L round bottom flask is fitted with a septum, a mechanical stirrer, and stopper. The flask is charged with 5-fluoro-3-methylbenzothiophene (55.4 g, 0.311 moles) and acetonitrile (350 mL). The mixture is stirred with a mechanical stirrer and the reaction temperature is monitored. NBS is added portion wise. The reaction temperature rises slightly, and the reaction is cooled with ice water bath. A solid crashes out of solution. The solid is filtered and rinsed 2 times with a 1:1 mixture of acetonitrile and water (100 mL). The solid is dried in a vacuum oven overnight at room temperature to obtain the title product (69 g, 95%). 1H-NMR (DMSO-d6), δ 2.41 (s, 3H), 7.34 (td, J=10, 2 Hz, 1H), 7.69 (dd, J=10, 2 Hz, 1H), 8.04 (dd, J=9, 5 Hz, 1H) ppm.

Provenance & Evidence