Synthesis of substituted 1,2-dihydropyridines by reaction of ethyl N-arylmalonamates with ethyl 2-(ethoxymethylidene)-3-oxobutanoate

Michael addition of ethyl N-arylmalonamates to ethyl 2-(ethoxymethylidene)-3-oxobutanoate in ethanol in the presence of triethylamine at room temperature afforded the corresponding adducts which underwent cyclization to diethyl 1-aryl-6-methyl-2-oxo-1,2-dihydropyridine-3,5-dicarboxylates in 17–65% yield. N-Alkylmalonamic acid esters failed to react with ethyl 2-(ethoxymethylidene)-3-oxobutanoate under analogous conditions.