Novel syntheses of symmetrical 2,5-diaryl-1,3,4-oxadiazoles and 1,4-phenylenebis-1,3,4-oxadiazoles

The reactions of trichloromethylarenes with excess hydrazine hydrate in ethanol gives symmetrical 2,5-diaryl-1,3,4-oxadiazoles in 68–96% yields. The reaction of 1,4-bis(trichloromethyl)benzene with acylhydrazines in an ethanol-pyridine mixture gives the corresponding substituted or unsubstituted 1,4-phenylenebis-1,3,4-oxadiazoles in 35–51% yields. The mass spectra of 2,5-diaryl-1,3,4-oxadiazoles and 1,4-phenylenebis-1,3,4-oxadiazoles were studied. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2309–2316, November, 1998.