A New Approach to the Synthesis of 4H-1,3,5-Oxadiazine Derivatives

Derivatives of 1,3,5-oxadiazine are of great interest as potential biologically active compounds. In this work, we report on a new method for synthesizing 1,3,5-oxadiazine derivatives. The method is based on the elimination of hydrogen sulfide from N-((1-carboxamido-2,2,2-trichloroethyl)carbamothioyl)benzamides by the action of dicyclohexylcarbodiimide (DCC). Presumably, at the first stage of the transformation, an intermediate carbodiimide is formed, which then enters into the [4+2] cycloaddition reaction with another DCC molecule to form the final products - N-(2,2,2-trichloro-1-(((2Z,4E)-3-cyclohexyl-2-(cyclohexylimino)-6-phenyl-2,3-dihydro-4H-1,3,5-oxadiazin-4-ylidene)amino)ethyl)carboxamides. Target products were obtained in 68-89% yields. The structure of the obtained compounds was confirmed by IR, 1H NMR, 13C NMR spectroscopy, and mass spectrometry.