Sodium Hydroxide → 2,6-Dimethyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid monomethyl ester

Participants

Reaction Steps

Dimethyl 2,6-dimethyl-4-(m-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate (17.3 g, 0.05 mole) is suspended in methanol (280 ml) and thereto a solution of NaOH (15.9 g, 0.4 mole) in water (52 ml) is added at room temperature under stirring. The reaction mixture is stirred at reflux temperature for 5 hours, cooled, water (1050 ml) is added under stirring and the resulting mixture is filtered. The precipitate is the unreacted starting compound, i.e. dimethyl 2,6-dimethyl-4-(m-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate. To the clear filtrate activated carbon (1 g) is added and the mixture is stirred at 50°-60° C. for 30 minutes. After cooling the activated carbon is filtered off, the filtrate is acidified with 1 n HCl to pH 2.5 and the precipitate is filtered and washed with water (2×15 ml). Thus, there is obtained the pure title compound (11 g, 66%), m.p. 202°-206° C.

Provenance & Evidence