Research in the isoxazole series

The thermal decomposition of phenylazotriphenylmethane in 3,5-dimethyl- and 3,4,5-trimethylisoxazole was studied. In 3, 5-dimethylisoxazole only the hydrogen atom of the methyl group in the 3 position is replaced by the (C₆H₅)₃C radical. The activities of the methyl groups of 3,4,5-trimethylisoxazole decrease in the order 3-C>4-C 5-C. The specific direction of the reaction is associated with the orientation of the phenylazotriphenylmethane in the vicinity of the 3-C atom of the isoxazole ring owing to complexing of the azo group with the nitrogen atom. Complexes of 3, 5-dimethyl- and 3, 4, 5-trimethylisoxazole with Eu⁺ have a similar structure. The structures of the reaction products were established by means of their PMR and mass spectra.See [1] for communication XXXII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 608–610, May, 1977.