A convenient three-step synthesis of the phosphorothioate analogue of phosphatidylethanolamine is described. The reaction pathway involves the conversion of a 1,2-diacyl-sn-glycerol to its corresponding thiophosphoric acid dichloride by using PSC13 in the presence of a tertiary base. Treatment of the dichloride with ethanolamine results in the formation of a cyclic thiophosphoramidate which, upon acidification, undergoes P-N cleavage, giving rise to 1,2-diacyl-sn-glycero-3-thiophosphorylethanolamine. 31P NMR reveals that both diastereoisomers are present in equivalent amounts. It is not possible, however, to separate the two isomers by high-pressure liquid chromatography. 31P NMR and high-pressure liquid chromatography are used to show that phospholipases A2 and C exhibit absolute and opposite stereoselectivity in the hydrolysis of the pair of diastereoisomers.
ASJC Scopus subject areas