Addition reactions of heterocyclic compounds. Part LVII. Reactions of pyridines with acetylenic esters in the presence of carbanion sources

Abstract

Pyridine, methylpyridines, isoquinoline, and acridine react with methyl propiolate and nitromethane to give mainly dihydro-N-trans-methoxycarbonylvinyl derivatives with a nitromethyl group usually para to the ring nitrogen atom. Replacing nitromethane by methyl acetoacetate or cyanoacetate, acetylacetone, or malononitrile, gives corresponding products. Acridine reacts with dimethyl acetylenedicarboxylate in nitromethane to give Diels and Alder's ‘red adduct,’ identified as tetramethyl pyrido[2,1-e]acridine-1,2,3,4-tetracarboxylate. The structures of the new compounds are deduced mainly from their n.m.r. spectra.