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-nitromethylenethiazolidine straightforwardly gives rise to the formation of (Z)-2-(nitro­((E)-p-substituted­phenyldiazenyl)­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.