Reactions of lysolecithin, phosphate esters and fatty acids with bromine in organic solvents

Abstract

Lysolecithin reacts with bromine in various solvents. The rate and nature of the reaction is solvent dependent. In solvents such as chloroform and benzene lysophosphatidic acids and choline are formed. In primary and secondary alcohols the corresponding alcohol esters of the lysophosphatidic acid are formed and choline is also liberated. No reaction occurs in tert-butanol. In isopropyl ether a new product is formed which contains all the ester, P, and choline of the original lysolecithin but which has a different chromatographic mobility on paper. This new product is tentatively identified as a mixed isopropyl ether fatty acid ester of glycerylphosphorylcholine. In alcohol the lysophosphatidic aicds are slowly broken down to glycerol phosphate (ester) and the fatty acid ester of the corresponding alcohol. Bromine also catalyzed the breakdown of glycerylphosphorylethanolamine and glycerylphosphorylserine in aqueous methanol to yield GP and the free N-base (ethanolamine or serine respectively). No reaction occurs with phosphorylethanolamine or phosphorylserine. Furthermore the reaction with lecithin is very slow. This data strongly suggests that a cyclic phosphate intermediate is involved in these bromine catalyzed reactions. Bromine catalyzes the esterification of stearic acid in various alcohols. The rate of reaction is fastest in methanol.