To a solution of 93 mg (0.223 mM) of 2-methoxy-3-octadecylcarbamoylthiopropylamine IVa6 and 40.4 μl (3.9 mM) of triethylamine in 5 ml of dichloromethane and 2 ml of tetrahydrofuran is added 29.8 μl (3.3 mM) of 3-chloropropanesulfonyl chloride with ice-cooling, and the mixture is stirred for 2 hours and at room temperature for an additional 30 minutes. The product is isolated by dichloromethane extraction and the dichloromethane layer is washed with an aqueous sodium hydrogencarbonate and a saturated aqueous solution of sodium chloride, dried over anhydrous magnesium sulfate, and evaporated. The residue is purified by the column chromatography on silica gel with a benzene-ethyl acetate (4:1) mixture as an eluent to give 83 mg (0.149 mM) of 3-(3-chloropropylsulfonylamino)-2-methoxy-1-octadecylcarbamoylthiopropane IIIa6 as a colorless powder in 67% yield.
