1-[N-Methyl-N-(2-hydroxyethyl)amino]-3-(12-hydroxyoctadecyl)-2-propanol was first prepared from 12-hydroxyoctadecyl glycidyl ether and N-methylethanolamine in the same manner as in the preparation of N-(3-methoxy-2-hydroxy-propyl)-N-methyl-2-hydroxyethylamine in Preparation Example 24. A 200-ml autoclave was charged with 6.3 g (15 mmol) of the thus-prepared compound, 100 ml of diethyl ether and 14.2 g of methyl bromide, and the resultant mixture was stirred at 48° C. for 8 hours. The reaction mixture was then concentrated under reduced pressure, and the resultant residue was dissolved in methanol. Diethyl ether was added to the solution to form crystals. The crystals were collected by filtration, thereby obtaining 6.9 g (yield: 90%) of the title compound (IIb-4).
