反应详情

A solution of 3β-acetoxy-24-hydroxy-5α-chol-8(14)-en-15-one (400 mg) in dry pyridine (3 ml) and a solution of p-toluenesulfonyl chloride (300 mg) in dry pyridine (2 ml) were cooled in sealed vials in a freezer, combined, and kept at 5° C. in a sealed vial for 24 h. The reaction mixture was poured onto ice and the solid product was collected on a filter and washed with water. Reversed phase HPLC analysis on a Microsorb C18 column (solvent, methanol) indicated the following composition: 3β-acetoxy-24-tosyloxy-5α-chol-8(14)-en-15-one, 95%; unreacted 3β-acetoxy-24-hydroxy-5α-chol-8(14)-en-15-one , 3%; and 3β-acetoxy-24-chloro-5α-chol-8(14)-en-15-one, 2%. The crude tosylate (497 mg) was subjected to chromatography on a silica gel (70-230 mesh) column (250 mm×14 mm). Using 5% ethyl acetate in hexane, fractions 20 ml in volume were collected. At fractions 39 and 77, the eluting solvent was changed to 20% ethyl acetate in hexane and 50% ethyl acetate in hexane, respectively. The contents of fractions 41-74 contained 3β-acetoxy-24-tosyloxy-5α-chol-8(14)-en-15-one (392 mg, 66% yield) with a purity of 99% as judged by HPLC analysis. Additional material (62 mg) of 95% purity was recovered in fractions 75-83. The contents of fractions 41-44 (171 mg) were recrystallized from ether-hexane to give 3β-acetoxy-24-tosyloxy-5α-chol-8(14)-en-15-one (150 mg) melting at 158.0°-159.5° C. The structure was confirmed using I.R., N.M.R., and M.S. analyses.

1. customkept at 5° C.
2. customsealed vial for 24 h
3. additionThe reaction mixture was poured onto ice
4. customthe solid product was collected on
5. filtrationa filter
6. washwashed with water
7. customwere collected