2-alkoxycarbonylcycloimmonium ylides, efficient 1,4-dipole equivalents in the synthesis of new conjugated betaines

Article abstract of DOI:10.1016/S0040-4020(01)89900-2

Several heterocyclic mesomeric betaines containing the bicyclic systems pyrido[1,2-a]pyrazine and pyrido [2,1-f][1,2,4]triazine have been prepared by reaction of 2-alkoxycarbonyl pyridinium N-ylides with phenyl isocyanate and isothiocyanate.