Mild oxidative cyclization of sydnone‐benzoylhydrazone with lead oxide to 2,5‐disubstituted‐1,3,4‐oxadiazole–sydnone hybrid derivatives

Abstract magnified image The mild oxidation of sydnone‐benzoylhydrazone hybrids with lead oxide in acetic acid/dichloromethane solution inducted their intramolecular cyclization to provide the corresponding 2,5‐disubstituted‐1,3,4‐oxidiazole derivatives. The sydnone moiety has been efficient preserved for the future work in the mild oxidation. J. Heterocyclic Chem., (2009).