The chemistry of pseudomonic acid, part II. Dehydrative cyclisation of α-acylamino ketones to oxazoles

Abstract

A number of mild methods for the preparation of 2-substituted 5-normonyloxazoles (1) by dehydrative cyclisation of the corresponding monamides (2) have been developed and are described. The preferred conditions involve using trichloroacetyl chloride, pyridine, and 4-N,N-dimethylaminopyridine. The stabilities of the vinyloxazoles to both the reaction conditions and to light are also reported.