N-alkylation of Hantzsch 1,4-dihydropyridines with esters of halogenocarboxylic acids

Abstract

1,4-Dihydropyridine derivatives IIIa,b,d,e and IVa,b,e were prepared from the corresponding Hantzsch dihydropyridines I and II by alkylation with ethyl halogenocarboxylates after deprotonation of the starting compounds with sodium hydride in dimethylformamide. Attempts to prepare compounds IIIc and IVc,d by this method failed. Spectral characteristics of the products and their fragmentation on electron impact are discussed.