| 摘要 |
<p>PURPOSE:To provide the subject derivative comprising an alkyl(22E)1alpha,3beta- disubstituted silyloxy-24-fluoro-24-methylhomochol-5,7,22-trien-25-oate and useful for the therapy of renal failure rachitis, osteoporosis, etc. CONSTITUTION:A 20(R)-formylmethyl-1alpha,3beta-disubstituted silyloxy-pregna-5,7-diene of formula I (R1, R2 are trialkylsilyl, triarylsilyl as hydroxyl group-protecting groups, etc.) is reacted with a 2-fluoropropionic acid alkyl ester and a lithium dialkylamide in an anhydrous ether solvent, and the reaction product is reacted with an alkylsulfonic acid chloride, etc., in the presence of a tertiary organic amine in an anhydrous hydrocarbon halide solvent to produce the objective alkyl (22E)-1alpha,3beta-disubstituted silyloxy-24-fluoro-24-methyl homochol-5,7,22-trien-25-oate of formula II (R3 is 1-3C alkyl).</p> |
