A solution (100 ml) of diethyl 2-acetamido-2-[2-(4-octylphenyl)ethyl]malonate (11.55 g) in anhydrous tetrahydrofuran was dropwise added to a solution (260 ml) of lithium aluminum hydride (3.0 g) in anhydrous tetrahydrofuran under ice-cooling. The mixture was stirred for 1 hour under ice-cooling and then at room temperature for 2 hours. A saturated aqueous solution of sodium sulfate was dropwise added under ice-cooling to decompose lithium aluminum hydride, which was then filtered off. The resultant mixture was extracted with ethyl acetate and the ethyl acetate layer was washed and dried. The solvent was distilled away and the residue was purified by silica gel column chromatography (chloroform/methanol=9/1) to give crystals of 2-acetamido-2-[2-(4-octylphenyl)ethyl]-1,3-propanediol, melting point 66°-68° C. The obtained compound was dissolved in pyridine (40 ml) and acetic anhydride (30 ml) was added thereto under ice-cooling. The mixture was left standing at room temperature overnight. The reaction mixture was poured into a 10% aqueous hydrochloric acid solution (500 ml) and extracted with ethyl acetate. The ethyl acetate layer was washed with an aqueous potassium hydrogencarbonate solution and saturated brine, and dried over anhydrous magnesium sulfate. The solvent was distilled away and the residue was purified by silica gel column chromatography (ethyl acetate/hexane=2/1) to give 8.25 g of the subject compound.
