On the base catalysed ring opening of 3-unsubstituted isoxazoles. Derivatives of 4- and 5-phenylisoxazole

Abstract

The kinetics of the base-induced decomposition of 4- and 5-phenylisoxazole and their p-bromo- and p-nitrophenyl derivatives, and 3-deuterio-5-phenylisoxazole, to the corresponding cyanoenolate anions have been studied. The mechanism of reaction has been established as a one-stage concerted abstraction of the proton in position 3 and scission of the N–O bond. 4-Phenylisoxazole, previously synthesized by laborious methods, has been prepared by a simpler procedure.