Synthesis of 1,4-Dihydropyridine Carboxylic Acids (II)

1,4-디하드로피리딘 산류의 합성(II)

2,6-dimethyl-4-(3'-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid 3-methyl 5-(2'-methylthio)ethyl ester methyl iodide salt (7a) was hydrolyzed by treatment with NaOH in aquous EtOH solution to give 2,6-dimethyl-4-(3'-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid mono methyl ester (2b) in 88% yield. By the same procedure, 2,6-dimethyl-4-(3'-nitrophenyl)-1,4-dihydropyridinine-3,5-dicarboxylic acid 3-mono isopropyl ester (2c), 2,6-dimethyl-4-(2'-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid 3-mono methyl ester (2d), 2,6-dimethyl-4-(2',3'-dichlorophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid 3-mono methyl ester (2e) and 2,6-dimethyl-4-(3'-nitrophenyl)-1,4-dihydropyridin-3,5-dicarboxylic acid (2f) were obtained from the methyl iodide salts in 91-98% yield.