Nitric Acid → 5-Methoxy-2-methyl-4-nitropyridine 1-oxide

Participants

Reaction Conditions

Reaction Steps

21.2 g of 5-methoxy-2-methylpyridine 1-oxide are metered into 35 ml of 65% strength nitric acid, warmed to 60° C., in a manner such that the temperature of the reaction mixture does not rise above 80° C. The mixture is stirred at 80° C. for 1 hour, a further 13 ml of 100% strength nitric acid are added to bring the reaction to completion and the mixture is stirred at 60°-70° C. for a further 2 hours. For working up, the mixture is poured onto 300 g of ice. The yellow precipitate which has separated out is filtered off over a suction filter, washed with water and dried. The dry solid is boiled up with 200 ml of methylene chloride, filtered off and dried. Further TLC-pure product is isolated by concentration of the filtrate. 22.3 g (87% of theory) of 5-methoxy-2-methyl-4-nitropyridine 1-oxide of m.p. 201°-202° C. are obtained; yellow crystals.

Provenance & Evidence