Process for the preparation of active-type vitamin D.sub.3 compo

Details Process for the preparation of active-type vitamin D.sub.3 compo Process for the preparation of active-type vitamin D.sub.3 compo

1982-04-26

1983-06-14

Roberts, Elbert L.

Chemistry of carbon compounds

Miscellaneous organic carbon compounds

C-metal

C07J 900

Patent

active

043882439

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.

REFERENCES:
patent: 3993675 (1976-11-01), Uskokovic et al.
patent: 4011250 (1977-03-01), Iskikawa et al.
patent: 4226788 (1980-10-01), De Luca et al.

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