| 摘要 |
1463985 Dihydroxy steroid-5-enes and vitamin D derivatives RESEARCH INSTITUTE FOR MEDICINE & CHEMISTRY Inc 10 Jan 1974 [10 Jan 1973 21 May 1973] 1257/74 Headings C2V and C2U In a process for the production of a 1α,3#- dihydroxysteroid - 5 - ene or a 1α - protectedhydroxyl derivative thereof, a corresponding 1α - hydroxy- or 1α,2α - epoxy - steroid - 4,6- dien - 3 - one or a 1α - hydroxy or 1α,2α- epoxy-steroid-4-ene having a readily eliminatable 6-substituent or a 1α-protected-hydroxyl derivative is reduced with an alkali metal or an alkaline earth metal in ammonia or a liquid amine in the presence of a proton source, e.g. an ammonium or amine salt or an alcohol. The steroid of the starting material may be a cholestene and the resulting 1α,3# - dihydroxycholesta-5-ene may be dehydrogenated to 1α,3# - dihydroxy - cholesta - 5,7 - diene which may be subjected to actinic radiation to obtain 1α-hydroxyprevitamin D; this may be isomerized by heating to 1α-hydroxy vitamin D, which in turn may be isomerized with iodine to the trans-isomer or may be subjected to further actinic radiation to produce the corresponding 1α-hydroxy-tachysterol derivative, which on reduction yields the corresponding 1α-hydroxy- 9,10-dihydrotachysterol derivative. In examples cholesterol is reacted with dichlorodicyanoquinone to obtain cholesta-1,4,6-trien-3-one which is oxidized with hydrogen peroxide to 1α,2α-epoxycholesta-4,6-dien-3-one and this is reduced with lithium metal in liquid ammonia containing ammonium chloride to 1α,3#-dihydroxycholest-5-ene; 1α2α-epoxycholesta-4,6- dien-3-one is reduced with zinc dust to 1α- hydroxycholesta - 4,6 - diene - 3 - one and this is converted to its trimethylsilyl ether and reduced with lithium metal, liquid ammonia and ammonium chloride to 1α,3#-dihydroxycholest- 5-ene; 1α,3#-dihydroxycholest-5-ene is converted to 1α,3#-dibenzoyloxycholest-5-ene and then reacted with dibromodimethylhydantoin to obtain 1α,3# - dibenzoyloxycholesta - 5,7 -diene which was hydrolysed and then irradiated to obtain 1α-hydroxy vitamin D 3 ; 25-hydroxycholesterol is reacted with dichlorodicyanoquinone to form the trienone and this is reacted with hydrogen peroxide to obtain 1α,2α-epoxy- 25 - hydroxycholesta - 4,6 - dien - 3 - one which is reduced with zinc dust to 1α,25-dihydroxycholesta - 4,6 - dien - 3 - one, converted to the trimethylsilyl ether and reduced with lithium and ammonia to 1α,3#-25-trihydroxycholest-5- ene; 1α,3#-diacetoxycholesta-5,7-diene is irradiated to the previtamin which is contacted with iodine to obtain the tachysterol derivative and, is also heated to obtain 1α-hydroxy vitamin D 3 , which is converted to 5,6-trans-vitamin by contact with iodine; cholest-5-ene is acetylated, brominated and dehydrobrominated to obtain 1α,3#,25-triacetoxycholesta-5,7-diene which is irradiated, heated and hydrolysed to 1α,25- dihydroxy vitamin D 3 , which on contact with iodine forms the trans-isomer. |
