Some transformations of N-ethoxycarbonyl-methylpyridinium bromides with a pyridyl or 1,4-dihydropyridyl substituent at position 3

Article abstract of DOI:10.1007/BF02256759

The direction of the reaction of derivatives of N-ethoxycarbonylmethylpyridinium bromide with chalcone in the presence of bases depends on the substituent at position 3 of the pyridine ring. In the presence of a pyridyl substituent a derivative of 2,3-dihydroindolizine is formed. In the case of a 1,4-dihydropyridyl substituent cycloaddition does not occur, and a Michael addition product (an acyclic betaine) is formed. The latter can be transformed into a derivative of indolizine only under the conditions of decarboxylation. 1997 Plenum Publishing Corporation.