19431-20-0Relevant academic research and scientific papers
Stereospecific reduction of keto group in 3β-triphenylmethoxy-5α -cholest-8(14)-en-15-one
Ignatov,Misharin
, p. 167 - 168 (2007/10/03)
The reduction of 3β-triphenylmethoxy-5α-cholest-8(14)-en-15-one with lithium aluminum hydride resulted in a quantitative yield of 3β-triphenylmethoxy-5α-cholest-8(14)-en-15β-ol.
Stereo and chemical course of acid-catalyzed double bond migration of cholesta-5,7-dien-3β-ol to 5α-cholesta-8,14-dien-3β-ol
Seto, Hideharu,Fujioka, Shozo,Koshino, Hiroyuki,Takatsuto, Suguru,Yoshida, Shigeo
, p. 1697 - 1703 (2007/10/03)
Acid-catalyzed double bond migration of steroid 5,7-dienes to the 5α-8,14-dienes, a well-known reaction in steroid chemistry, was reinvestigated by using cholesta-5,7-dien-3β-ol 1, and the stereo and chemical course of this reaction was detailed. Treatment of 1 with 36% hydrochloric acid in refluxing ethanol for 3 h afforded a 6:11:65:16:2 mixture of dienols (93%): 5α- and 5β-cholesta-6,8(14)-dien-3β-ols 7a,b, 5α- and 5β-cholesta-8,14-dien-3β-ols 2a,b, and 5α-cholesta-14,16-dien-3β-ol 10a, along with a mixture of enones (1.7%): 5β-cholest-8(14)-,5β-cholest-14- and 14-epi-5β-cholest-8-en-3-ones 11-13. The experiments using 7a,b and 2a,b suggested the reaction sequence: 1→7a,b?7,14-dienols 8a,b?2a,b?8(14),15-dienols 9a,b?10a,b, in which 8a,b?9a,b should be also implicated. The initial step, 1 to 7a,b proceeded irreversibly with the stereoselectivity, ca. 7:3 of 5α-H to 5β-H. Dienols 7a, 8a, 2a and 10a with 5α-H were identified, which were equilibrated at 6:0:92:2. Among dienols with 5β-H, only 7b and 2b were identified, which were equilibrated at 2:98, and this interconversion proceeded in competition with an intramolecular hydride shift from the C-3α to C-6α of 7b, leading to the formation of a mixture of enones 11-13. The considerable difference in activation energies between 1→7a,b and 7a,b→8a,b/11-13 realized the predominant formation of 7a,b: by treatment at 30°C for 44 h, 1 gave a 53:27:5:15 mixture (94%) of 7a, 7b, 8a and 2a. The Royal Society of Chemistry 2000.
Synthesis of meiosis-activating sterols containing fluorine
Wenckens, Martin,Gronvald, Frederik,Hansen, John Bondo
, p. 503 - 507 (2007/10/03)
It is documented that specific types of sterol play a major role in the resumption of meiosis in oocytes from mice in vitro. 4,4-Dimethyl-5α-cholesta-8,14,24-trien-3β-ol (FF-MAS) isolated from human follicular fluid and 4,4-dimethyl-5α-cholesta-8,24-dien-3β-ol (T-MAS) isolated from bull testicular tissue, have been shown to activate (promote) meiosis in vitro. In order to evaluate the biological activity and stability of such compounds, new demethylsterol derivatives have been synthesised. Using diethylaminosulfur trifluoride (DAST) it was possible to synthesise selected Δ8, Δ14 sterols with mono and difluoro substitution at C3. Acta Chemica Scandinavica 1998.
