Amide and thioamide of cyanoacetic acid in АdNE type reactions with 2-halopyridinium salts

Abstract

A mixture of pyridine-2-thiones and 2-amino-1-cyanoindolizines was obtained by condensation of N-[(alkoxycarbonyl)methyl]- or N-[(aroyl)methyl]-2-chloro(bromo)pyridinium halides in the presence of 2 equivalents of triethylamine. Furthermore, reacting cyanoacetamide with N-[(alkoxycarbonyl)methyl]-2-chloro(bromo)pyridinium salts afforded a mixture of 2-amino-1-carbamoylindolizine-3-carboxylates and a novel heterocyclic system, 2,4-dioxo-2,3,4,5-tetrahydropyrido[1,2-d][1,4]diazepine-1-carbonitrile.