Water → 2,4-Dibromothiazole-5-carboxamide

Participants

Reaction Steps

A suspension of 2,4-dibromo-1,3-thiazole-5-carboxylic acid (16.33 g, 56.91 mmol) in dry DCM (250 mL) and DMF (0.400 mL) was cooled in an ice bath. Thionyl chloride (40.0 mL, 548 mmol) was added dropwise. The cooling bath was removed and the suspension was stirred at rt for 2.5 hours. Toluene (80 mL, 800 mmol) was added and the suspension was heated to reflux for 1 hour. The mixture was cooled to room temperature, the solvent was removed and the residue was azeotroped with toluene (2×100 mL) to give a crude intermediate. This material was suspended in DCM (230 mL) and cooled in an ice bath. N,N-Dimethylaminopyridine (0.70 g, 5.7 mmol) was added, followed by the slow addition of 8.5 M ammonium hydroxide in water (100.0 mL, 850.0 mmol). The mixture was stirred at room temperature overnight. The mixture was filtered and the aqueous layer was separated and extracted with DCM (3×100 mL). The combined DCM layers were washed with water, brine, dried over Na2SO4, filtered, and evaporated to give a solid product (11.2 g, 69%). LCMS: (FA) ES+ 287 and ES− 285.

Provenance & Evidence