Reaction of hydroxylamine with 5‐aminooxazoles. A new route to isoxazoles

Abstract

Abstract The nucleophilic attack of hydroxylamine at the 5 position of 2‐aryl‐4‐trifluoroacetyl‐5‐amino‐oxazoles leads to a mixture of stereoisomeric isoxazolines. Dehydration of these isomeric isoxazolines in the presence of trifluoroacetic anhydride gives 3‐amino‐4‐acylamino‐5‐trifluoromethylisoxazoles. The structures and spectroscopic data of these compounds are discussed.