To a solution of 3.6 gm of the tetrafluoroborate salt of the allyl ester of L-carnitine and 4.5 gm of collidine in 25 ml of acetonitrile is added 5.7 gm of dichlorotetradecylphosphite in 25 ml of acetonitrile. The reaction mixture is stirred at room temperature for 17 hours, and then a solution of 4 gm of sodium metaperiodate in 20 ml of water is added. After stirring at room temperature for two hours, the reaction mixture is filtered through Celite; and the filtrate is concentrated under vacuum. The resulting residue is flash chromatographed on silica gel, initially with a 50/30/5 ratio of methylene chloride/methanol/concentrated ammonium hydroxide and then with a 50/30/8 ratio of the same solvent system. Subsequent flash chromatography on LiChroprep RP-8 silica gel eluting initially with water and then with methanol gave N,N,N-trimethyl-4-oxo-4-[(2-propenyl)oxyl]-2-[{hydroxy(tetradecyloxy)phosphinyl}oxy]-1-butanaminium hydroxide, inner salt as an amorphous solid (31P NMR=0.108 ppm).
