反应详情

(2)-(1) A solution of 2-chlorobenzaldehyde (14.0570 g), ethyl 4,4-diethoxyacetoacetate (21.8240 g) and piperidine (1 ml) in benzene (100 ml) was refluxed under azeotropic dehydration for 4 hours. The resultant solution was washed with water, dried and concentrated to give oily ethyl 2-(2-chlorobenzylidene)-4,4-diethoxyacetoacetate. The mixture of the compound obtained above and ethyl 3-aminocrotonate (12.92 g) was heated in an oil bath (about 100° C.) for 8 hours. The reaction mixture was dissolved in ethyl acetate, washed with water, dried and then the solvent was removed to give crude oil (52.4 g). The oil was purified by column chromatography on silica gel with an eluent (benzene:ethyl acetate=20:1) to give diethyl 2-methyl-4-(2-chlorophenyl)-6-diethoxymethyl-1,4-dihydropyridine-3,5-dicarboxylate, which was recrystallized from n-hexane to give the pure crystals (20.2445 g), m.p. 75° to 77° C.

1. washThe resultant solution was washed with water
2. customdried
3. concentrationconcentrated