Syntheses of 4-(5-oxo-1,2,4-triazol-3-yl)-sydnones and 4-(4-arylamino-5-oxo-1,2,4-triazol-3-yl)-sydnones from sydnone derivatives and their fragments

4-(5-oxo-1,2,4-triazol-3-yl)-sydnones 11 and 4-(4-arylamino-5-oxo-1,2,4-tri azol-3-yl)-sydnones 13 have been obtained from a-chloroformylarylhydrazine hydrochloride 2. Moreover, the intermediates, including 3, 4, 9 and 10, in this study are synthetically informative and valuable. It is also noteworth y that three reactants, 1, 2 and sydnonecarbaldehydes, were prepared from s ydnone derivatives and their fragments. The oxidative cyclizations of sydno necarbaldehyde semicarbazones 9 and carbazones 10 with two different oxidiz ing agents (Cu(ClO4)(2) and Fe(ClO4)(3)) have been extensively examined. Th e reaction time and the yields of cyclizations were affected by the substit uents of semicarbazones 9 and carbazones 10.