Synthesis of 28-O-(1,2-Diacyl-sn-glycero-3-phospho)-betulin

Abstract Novel phospholipid derivatives of betulin (1), betulin diacylphosphatides (3a, c), were obtained by coupling betulin (1) with 1,2-dipalmitoyl-sn-glycero-3-phosphatidic acid (2a) or its salt (2b) or with 1,2-diacyl-sn-glycero-3-phosphatidic acid (2c), obtained from phosphatidylcholine isolated from egg yolk. The syntheses were carried out with application of various coupling agents: 2-mesitylenesulfonyl chloride, p-toluenesulfonyl chloride, and N,N′-dicyclohexylcarbodiimide and in the presence of 4-dimethylamino-pyridine in pyridine.