Structural characterization of new 2-aryl-5-phenyl-1,3,4-oxadiazin-6-ones and their N-aroylhydrazone precursors

A series of novel 2,5-disubstituted 1,3,4-oxadiazin-6-ones and their N-aroylhydrazone precursors were synthesized and characterized by NMR and UV–Vis spectroscopy. The electronic properties of 2-aryl-5-phenyl-1,3,4-oxadiazin-6-ones are mainly dependent on the 2-aryl substituent and their absorption maxima exhibit a red shift in dichloromethane. Single crystal X-ray diffraction on four acylhydrazones indicated the isolation of isomer with Z configuration of the CN double bond. Intermolecular interactions through strong H-bonding and CH⋯π contacts serve to link the molecules into a three-dimensional supramolecular network.