Abstract
Bisnorcholenal 3-tetrahydropyranyl ether (1), obtained from bisnorcholenic acid in 3 steps, was coupled with lithium acetylide derived from 2-methyl-3-butyn-2-ol tetrahydropyranyl ether to give in 74% yield a 1 : 1 mixture of the cholest-5-ene-3β, 22, 25-trihydroxy-23-yne 3, 25-bis (tetrahydropyranyl) ethers, 2a and 2b. After resolution of the C-22 epimers and determination of their conflgurations, both isomers were converted to 22, 25-dihydroxycholesterol 3, 22-diacetates, 5a and 5b, and to 25-hydroxy-22-methoxycholesterol 3-acetate, 8a and 8b. These compounds were converted to (22R)-and (22S)-22, 25-dihydroxyvitamin D3, 12a and 12b, and to 25-hydroxy-22-methoxyvitamin D3, 14a and 14b, through the corresponding cholest-5, 7-diene-3β, 22, 25-triol 3, 22-diacetates (9a and 9b) and cholest-5, 7-diene-22-methoxy-3β, 25-diol 3-acetates (10a and 10b). According to preliminary biological testes, 22, 25-(OH)2D3 and 22-CH3O-25-OH-D3 have neither vitamin D activity nor antivitamin D activity.
