The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 14, 1983
Filed:
Apr. 26, 1982
Osamu Nishikawa, Iwakuni, JP;
Kenji Ishimaru, Iwakuni, JP;
Toru Takeshita, Hino, JP;
Hideki Tsuruta, Iwakuni, JP;
Teijin Limited, Osaka, JP;
Abstract
The present invention relates to a novel process for the preparation of active-type vitamin D.sub.3 compounds and their intermediates. In accordance with the present invention, a large amount of an active-type vitamin D.sub.3 compounds, for example 1.alpha.-hydroxycholecalciferol, 1.alpha.,25-dihydroxycholecalciferol and the like, is efficiently prepared with high industrial advantages by a novel processes, which comprises (i) reacting hydroxycholesta-5-enes having the hydroxyl groups protected with lower alkoxycarbonyl group as a starting material with allylic brominating agent and 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 D.sub.3 compounds or a mixture of the unreacted hydroxycholesta-5,7-dienes and the protected active-type vitamin D.sub.3 compounds, (iii) separating the mixture into the unreacted hydroxycholesta-5,7-dienes and previtamin D.sub.3 compounds or the protected active-type vitamin D.sub.3 compounds, (iv) recycling the unreacted hydroxycholesta-5,7-dienes as reuse and (v) thermally isomerizing the remaining compounds and/or splitting off the protective groups. The process for the preparation of active-type vitamin D.sub.3 compounds, in the present invention, is of very high industrial value, capable of carrying out by simple operation and adaptable to large scale commercial production.