Facile Synthesis and Structure of Novel 2,5‐Disubstituted 1,3,4‐Selenadiazoles

The reaction of hydrazide with carbonyl chloride in the presence of sodium carbonates leads to the corresponding 1,2‐diacylhydrazines [1a–t, R1C(O)NHNHC(O)R2, R1 = aryl, R2 = aryl or alkyl] in moderate to excellent yield (57–90 %). The latter reacts with 2,4‐diphenyl‐1,3‐diselenadiphosphetane‐2,4‐diselenide (Woollins' reagent, WR) in refluxing toluene to give a series of new 2,5‐disubstituted 1,3,4‐selenadiazoles (2a–t, 51–99 % yield). All compounds were characterized spectroscopically and six compounds were characterized crystallographically. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)