Microwave-Assisted Coupling Reaction of N-Aryl Sydnones with 2-Nitromethylenethiazolidine: Unexpected Formation of (Z)-2-(Nitro((E)-p-substitutedphenyldiazenyl)methylene)thiazolidines

Reaction of N-aryl sydnones with 2-nitro-methylenethiazolidine straightforwardly gives rise to the formation of (Z)-2-(nitro((E)-p-substitutedphenyldiazeny1)methylene)thiazolidines in xylene and dimethoxyethane under microwave irradiation. A meaningful and plausible mechanism for this transformation is proposed, which anticipates the extrusion of an aceto-lactone-like moiety before a coupling occurs. The structures of all the new compounds were identified on the basis of the data obtained from the NMR, IR. X-ray diffraction spectra, HRMS measurements, and physical characteristics.