摘要:
                                Condensation of isovaleraldehyde with cyanothioacetamide and ethyl acetoacetate (or its enamine) gives 3-cyano-5-ethoxycarbonyl-4-isobutyl-6-methyl-3,4-dihydropyridine-2(1H)-thione. This compound was used in the synthesis of substituted 1,4-dihydropyridin-2-yl sulfides.