Abstract-Dehydrogenation of 1-(diphenylphosphinoyl)-2-hydrazino-substituted ethanes and N-butyl-N<- phenylhydrazine to the corresponding hydrazone derivatives is performed. Both reactions were established to involve predominantly, if not exclusively, an azo intermediate. DOI: 10.1134/S1070363206110144 ... Recently we found [1, 2] that triphenyl- and tri- butylhydrazinoethylphosphonium salts, even under moderate heating in alcohol or acetonitrile, are de- hydrogenated to ...