It has been revealed that 1-azirines having an ester function at C can be synthesized by the thermally induced skeletal rearrangement of 5-alkoxyisoxazoles and 5- alkylmercaptoisoxazles. Characterization of the azirines obtained was made by chemical reactions as well as by spectrometry. A further thermal transformation of azirine esters into oxazole derivatives could not be found. Mass spectra of representative 1-azirines are ...
