反应详情

A portion (58.3 mg) of the product from Example 1 is transferred to a 3-necked, 200 ml, round-bottomed flask equipped with a gas dispersion tube, gas exit bubbler and a thermometer. A charge of 150 mg of anthracene in 150 ml of benzene is added and the resulting solution irradiated at 10° C. (cold room) under a steady stream of nitrogen gas using 3-22 watt, circular fluorescent light bulbs. After 42 h of irradiation, TLC indicates the complete disappearance of a spot co-migrating with 5,6-trans-1α-hydroxyvitamin D3 and the appearance of a new spot co-migrating with 1α-hydroxyvitamin D3. After 45 h of irradiation the reaction is worked up by evaporation of the solvent. The residue is taken up in 15 ml of ether and filtered. The precipitate is washed with ether (3 ml, 3×). The combined filtrate and washings are evaporated and the residue applied in benzene to a 1×55 cm silica gel column. The column is eluted with benzene then with ethyl acetate/hexane mixtures, to yield 45 mg of a white powder shown to be identical with 1α-hydroxyvitamin D3 by comparison of nmr, uv, mass spectra and chromatographic properties with those of an authentic sample of this compound (prepared from 1α-hydroxycholesterol). Utilizing procedures essentially similar to that described above, but substituting other appropriate 5,6-trans-vitamin D compounds for 5,6-trans-1α-hydroxyvitamin D3, there is obtained 1α-hydroxyvitamin D2 from 5,6-trans-1α-hydroxyvitamin D2 ; 1α,25-dihydroxyvitamin D3 from 5,6-trans-1α,25-dihydroxyvitamin D3 ; 1α,24,25-trihydroxyvitamin D3 from 5,6-trans-1α,24,25-trihydroxyvitamin D3 ; 1α,25,26-trihydroxyvitamin D3 from 5,6-trans-1α,25,26-trihydroxyvitamin D3 ; 1α,24-dihydroxyvitamin D2 from 5,6-trans-1α,24-dihydroxyvitamin D2 ; 1α,25-dihydroxyvitamin D2 from 5,6-trans-1α,25-dihydroxyvitamin D2 ; 1α,24,25-trihydroxyvitamin D2 from 5,6-trans-1α,24,25-trihydroxyvitamin D2.