5-Methoxycarbonyl-6-dimethoxymethyl-2-methyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3-carboxylic acid → 6-Formyl-5-methoxycarbonyl-2-methyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

A solution of 3-nitrooxy-2,2-bis(nitrooxymethyl)propyl ester of 5-methoxycarbonyl-6-dimethoxymethyl-2-methyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3-carboxylic acid (7.50 g) dissolved in a mixture of 6N hydrochloric acid (22.5 ml) and acetone (90 ml) was stirred for 6.5 hours at 20° C. The resulting mixture was evaporated under reduced pressure. The residue obtained was dissolved in ethyl acetate, and washed successively with water, an aqueous sodium bicarbonate and an aqueous sodium chloride. The ethyl acetate solution was dried over anhydrous magnesium sulfate and evaporated under reduced pressure. The residue obtained was subjected to column chromatography on silica gel (200 g) and eluted with a mixture of toluene and ethyl acetate (10:1 by volume). The fractions containing the desired compound were collected and evaporated under reduced pressure and recrystallized from a mixture of ethyl acetate and diisopropyl ether to give yellow crystals of 3-nitrooxy-2,2-bis(nitrooxymethyl)propyl ester of 6-formyl-5-methoxycarbonyl-2-methyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3-carboxylic acid (5.23 g), mp 125° to 125.5° C.

Provenance & Evidence