Preparation of Lecithin-Type of Phospholipid Analogues and Mesomorphic States

Enol phosphates (3), arising from reaction of vinylene carbonate-tetrachloromethane telomers (2) with phosphite, were readily converted by successive procedures involving hydrolytic cleavage of carbonate rings, acylation and introduction of ethylamine moieties, to the unnatural types of cephalin and lecithin analogues, which possessed saturated long (C18 : 0) and short (C8 : 0) chains. Two kinds of fatty acid residues were selectively introduced by monoacylation with acid anhydrides followed by treatment with acid chlorides. Use of phosphonite in place of phosphite gave the same type of enol phosphonate which may serve for phosphono-lipid preparation. Synthetic phospholipid analogues thus formed exisist in thermotropic and lyotropic liquid crystalline states within definite temperature range. Their phase transition temperatures and Craft points as well as the lipid-water binary phase diagrams were compared with those of the corresponding natural phospholipids.