| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain the subject compound high in activity of binding to a vitamin D acceptor, not very high in function of increasing calcium content in the blood, more excellent in safety and useful as calcium metabolism improver. SOLUTION: This compound is shown by formula I (R<1> to R<3> are each H or hydroxyl protective group), e.g. (20S, 22S)-22-ethyl-23,24-dehydro-24,24- dihomo-1α,25-dihydroxyvitamin D3 . The compound shown by the formula I is obtained by a series of steps; (A) aldol condensation of a compound shown by formula II with a compound shown by formula III, (B) reduction of the unsaturated ketone as the dehydration product, to produce unsaturated alcohol, (C) reaction of the unsaturated alcohol with orthoacetic ester, (D) reduction of the product of the step C, (E) reaction of the product of step D with an organic sulfonyl halide in the presence of a base, and (F) reduction of the product of the step E and optical or thermal isomerization of the reduced product.</p> |
