The mechanisms of the photochemical conversion of isoxazoles to oxazoles and ketoketenimines have been investigated. Isonitrile 14 was detected by an ir band at 2160 cm- l in the photoconversion of 5 to 15 at-77'. Compound 14 was further identified by independent synthesis and by hydrolysis to formamide 17 in acid. Ir bands at 1690 and 1655 cm-l are consistent with the hypothesis that azirine 13 is the precursor to isonitrile 14. It is ...
