1,3-Dipolar reactivity in N-acylimino-derivatives of mesoionic ring systems
Abstract
N-Acylsydnone imines, anhydro-4-N-benzoylimino-2,3-diphenylthiazolium hydroxide, and anhydro-4-N-benzoylimino-2,3-diphenyl-1-methylimidazolium hydroxide undergo 1,3-dipolar cycloaddition with dimethyl acetylenedicarboxylate with the formation of substituted pyrazoles, the thiophen and pyrrole, respectively.