A solution of 1-O-octadecyl-3-O-trityl-glycerol (173.51 g, 295.63 mmol) in 895 mL water-free pyridine is added dropwise to a solution of p-toluenesulfonyl chloride (88.49 g, 464.15 mmol) in 670 mL water-free pyridine with constant stirring. The reaction mixture is kept at ambient temperature (20-23° C.) for two days. Diethyl ether (2.8 L) is added, and the organic phase is washed six times with water, twice with 0.5 N HCl (500 mL each), twice with diluted aqueous sodium carbonate, and then washed with water until neutral. After drying the organic phase over sodium sulfate, the solvent is removed under vacuum. The residue is triturated with isopropanol (1140 mL) with stirring until the product crystallizes. After cooling to 4° C., the product, 1-O-octadecyl-2-O-p-toluenesulfonyl-3-O-trityl-glycerol, is isolated by filtration, washed with isopropanol and dried under vacuum. Yield: 190.14 g (86.91%); m.p. 56-58° C.; Rf value (TLC on silica gel 60) of 0.38 with benzene as the developing solvent; and Rf value of 0.74 with benzene/methanol (50/2).
