Synthesis of 4-(5-aryl-1 3,4-oxadiazol-2-yl)phenyl-hydrazine derivatives from 3-(4-hydrazinocarbonyl-phenyl)sydnones

The synthesis of potential fluorescent active 4-(5-aryl-1,3,4-oxadiazol-2-yl)phenylhydrazine derivatives was accomplished in three steps. The key step was the dehydration cyclization of 1,2-diacylhydrazines to form the 1,3,4-oxadiazole ring by use of acetic anhydride/perchloric acid mixture as the dehydrating agent. The sydnone moiety served as the masked hydrazines, which could be demasked by HCl for further application. (c) 2007 Wiley Periodicals, Inc.