Triethylamine → 1-(4-Bromo-2,5-difluorophenyl)-N,5-dimethoxy-N-methyl-4-oxo-1,4-dihydropyridazine-3-carboxamide

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Reaction Steps

A mixture of 1-(4-bromo-2,5-difluorophenyl)-5-methoxy-4-oxo-1,4-dihydropyridazine-3-carboxylic acid. (25 g, 83 mmol), N,O-dimethylhydroxylamine hydrochloride (8.9 g, 91 mmol), HOBt (12 g, 91 mmol), triethylamine (24 mL, 174 mmol) and WSC (17 g, 91 mmol) in DMF (160 mL) was stirred at room temperature for 18 h. The mixture was diluted with AcOEt, washed with water and brine, dried over MgSO4 and concentrated under reduced pressure. The residue was purified by silica gel column chromatography eluting with Hexane/AcOEt (1/0 to 0/1) and then AcOEt/MeOH (10/1) to give the title compound (11 g, 31% yield) as a yellow solid: LC-MS (ESI) m/z 405 [M+H]+.

Provenance & Evidence