Process for the preparation of active-type vitamin D3 compounds and of the cholesta-5,7-diene precursors, and products so obtained
申请人:TEIJIN LIMITED
公开号:EP0028484A1
公开(公告)日:1981-05-13
The present invention relates to a novel process for the preparation of active-type vitamin D3 compounds and their intermediates. In accordance with the present invention, a large amount of an active-type vitamin D3 compound, for example 1α-hydroxycholecalciferol, 1α,25-dihydrox- ycholecalciferol and the like, is efficiently prepared with high industrial advantage by a novel process which comprises (i) reacting hydroxycholesta-5-enes having the hydroxyl groups protected with lower alkoxycarbonyl groups as a starting material with an allylic brominating agent and a dehydrobrominating agent to prepare the corresponding hydroxycholesta-5,7-dienes, (ii) exposing the hydroxycholesta-5,7-dienes to ultraviolet irradiation or to a combination of the irradiation with thermal isomerization to obtain a mixture of the unreacted hydroxycholesta-5,7-dienes and previtamin D3 compounds or a mixture of the unreacted hydroxycholesta-5,7-dienes and the protected active-type vitamin D, compounds, (iii) separating the mixture into the unreacted hydroxycholesta-5,7-dienes and previtamin D3 compounds or the protected active-type vitamin D3 compounds, (iv) recycling the unreacted hydroxycholesta-5,7-dienes for reuse and (v) thermally isomerizing the remaining compounds and/or splitting off the protective groups. The process of the invention is of very high industrial value, capable of simple operation and adaptable to large scale commercial production.
本发明涉及一种制备活性型维生素 D3 化合物及其中间体的新工艺。根据本发明,大量活性型维生素 D3 化合物,例如 1α-羟基胆钙化醇、1α,25-二羟基胆钙化醇等、该工艺包括:(i) 以羟基被低级烷氧羰基保护的羟基胆甾烷-5-烯为起始原料,与烯丙基溴化剂和脱氢溴化剂反应,制备相应的羟基胆甾烷-5,7-二烯;(ii) 将羟基胆甾烷-5、(ii) 将羟基胆甾烷-5,7-二烯置于紫外线辐照下,或将辐照与热异构化相结合,以获得未反应的羟基胆甾烷-5,7-二烯与前维生素 D3 化合物的混合物,或未反应的羟基胆甾烷-5,7-二烯与受保护的活性型维生素 D 化合物的混合物、(iii) 将混合物分离为未反应的羟基胆甾烷-5,7-二烯和前维生素 D3 化合物或受保护的活性型维生素 D3 化合物, (iv) 回收未反应的羟基胆甾烷-5,7-二烯以供再利用, (v) 对剩余化合物进行热异构化和/或分离保护基团。本发明的工艺具有极高的工业价值,操作简单,可适应大规模商业生产。