Pyridine → 4-bromo-2,5-difluoro-N-[3,5-dimethyl-4-[(nitromethyl)sulphonyl]phenyl]benzenesulphonamide

Participants

Reaction Steps

1.3 g (16.4 mmol) of pyridine, dried over potassium hydroxide, and then 3.6 g (12.3 mmol) of 4-bromo-2,5-difluorobenzenesulphonyl chloride are added to a solution, maintained under a nitrogen atmosphere, of 2.0 g (8.19 mmol) of 3,5-dimethyl-4-[(nitromethyl)sulphonyl]aniline in 40 ml of anhydrous tetrahydrofuran. The reaction medium is stirred for 7 h 30 min at room temperature and then for 11 h at reflux; after cooling, it is poured into 300 ml of water and extracted 3 times with methylene chloride. The combined organic extracts are washed with water, dried over sodium sulphate and concentrated to dryness under reduced pressure. The solid residue obtained is purified by chromatography on a column of silica (eluent: methylene chloride) and recrystallization from a mixture of hexane and ethyl acetate, to give 0.24 g (6.2%) of 4-bromo-2,5-difluoro-N-[3,5-dimethyl-4-[(nitromethyl)sulphonyl]phenyl]benzenesulphonamide, containing 5 mol % of ethyl acetate.

Provenance & Evidence