3-(Dimethylaminomethylidene)-6-methylpyran-2,4-dione → 4-Hydroxy-6-methyl-nicotinic acid

Participants

Reaction Conditions

Reaction Steps

A mixture of 3-(dimethylaminomethylene)-4-oxo-6-methyl-2-pyrone (85.0 g) and ammonium hydroxide (500 ml) is slowly heated to 70° C. with the condenser outlet open. The mixture is heated at 70°-80° C. for 3 hours, concentrated to a volume of about 100 ml and acidified with 3N HCl to pH 5. The product is filtered and washed with water and diethyl ether to give 38.6 g of the title compound. Physical characteristics are as follows:

Provenance & Evidence