1.0 g of 3β-amino-7α,12α-dihydroxy-5β-cholan-24-oic methylester (FIG. 5A-1) [see Example I] was dissolved in 30 ml dry dimethylformamide and treated with 15 ml triethyl amine under stirring. 1.0 g of arachidoyl chloride in 10 ml dimethylformamide was added dropwise to the resulting solution, and the stirring was continued overnight. The reaction mixture was poured into water, extracted with methylene chloride, the organic fraction was then dried over sodium sulfate, evaporated to dryness and chromatographed over silica gel with a mixture of ethyl acetate and hexane (6:4 and 8:2), to give 0.6 g 3β-arachidylamido-7α,12α-dihydroxy-5β-cholan-24-oic methylester (FIG. 5A-4).
