The formation of 2-benzyloxyoxazol-5(4H)-ones from benzyloxycarbonylamino-acids

Abstract

The cyclodehydration of benzyloxycarbonylamino-acids by successive treatment with acid chloride-forming reagents and triethylamine has been shown to give 2-benzyloxyoxazol-5(4H)-ones, not N-benzyloxycarbonylaziridinones as reported previously. The 2-benzyloxyoxazol-5(4H)-ones, which are the first 2-alkoxyoxazol-5(4H)-ones to be described, are more easily attacked by nucleophiles at position 5 and less easily ionised at position 4 than their well known 2-aryl and 2-alkyl analogues.