Development of a Diversity-Oriented Approach to Oxazole-5-amide Libraries

A highly versatile route to oxazole-5-amides is presented. Conversion of readily accessible oxazole-5-trifluoroacetamides into their Boc-protected 5-aminooxazole derivatives provides intermediates amenable to parallel amide synthesis utilizing a reliable, one-pot, acylation−deprotection procedure. During preparation of the N-Boc compounds from trifluoroacetamides, a competing intramolecular rearrangement giving rise to novel N-(oxazol-5-yl)-2,2,2-trifluoroacetimidates was identified, the extent of which is primarily determined by the choice of reaction conditions.