反应详情

20 ml (270 mmol) of thionyl chloride and 1 ml of dimethylformamide are added respectively to 12.5 g (90 mmol) of 2-hydroxynicotinic acid in suspension in a mixture of 80 ml of dichloromethane and 20 ml of 1,2-dichloroethane. The suspension is stirred at reflux for 2.5 hours. The reaction mixture is cooled to room temperature and the precipitate formed is filtered to yield (11.98 g) of 2-hydroxynicotinic chloride. The solid is suspended in 150 ml of dichloromethane, and then 7.42 g (76 mmol) of N,O-dimethylhydroxylamine hydrochloride and 21.37 ml (152 mmol) of triethylamine are added successively. The reaction mixture is stirred for 2 hours at room temperature, the solvent is evaporated, and then the solid is taken up in a minimum of ethyl acetate (70 ml). The solid is filtered (triethylamine salt) and the filtrate is concentrated to yield after purification by silica gel chromatography (eluent: 10:1 dichloromethane/methanol) 10.5 g (64%) of N-methoxy-N-methyl-2-oxo-1,2-dihydropyridine-3-carboxamide in the form of a white solid.

1. temperatureat reflux for 2.5 hours
2. customthe precipitate formed
3. filtrationis filtered