The preparation and mass spectrometric studies of carboxy-substituted oxazoles derived from (S)-serine

Abstract

The copper(11) complex formed by the reaction of bis((S)-serinato)copper(11) and formaldehyde under alkaline conditions was treated with sodium borohydride to give the sodium salt of dihydro-1 H,3H,5H- oxazolo[3,4-c]oxazole-7a-carboxylic acid. This reaction does not cause appreciable cleavage of the oxazole ring system. The methyl and ethyl esters of the acid were prepared and characterized by gas chromatography/mass spectrometry (g.c.-ms.). Breakdown patterns involving loss of formaldehyde are described.