N-bromobutanimide → HCID 90092720, compound

Participants

Reaction Steps

A solution of [1-methyl-3-(thiophen-3-yl)-1H-pyrazol-5-yl]methanol (4b) (271 mg, 1.39 mmol) and N-bromosuccinimide (236 mg, 1.32 mmol) in acetonitrile (23 mL) was stirred at room temperature for 1 hour. The reaction mixture was concentrated in vacuo. Water (10 mL) was added and the aqueous layer was extracted with ethyl acetate (2×12 mL). The organic layer was dried over sodium sulfate and concentrated in vacuo. The residue was taken in dichloromethane (5 mL) and manganese dioxide (1.21 g, 13.95 mmol) was added. The reaction mixture was stirred at room temperature for 24 hours, filtered over Celite®, and the filtrate was concentrated in vacuo. to provide 4-bromo-1-methyl-3-(thiophen-3-yl)-1H-pyrazole-5-carbaldehyde (4c) (297 mg, 1.10 mmol, 78%), which was used without further purification.

Provenance & Evidence