Substitution und Elimination durch Aluminiumoxyd: 3-Benzoyloxycholesten-(1) und 1-Benzoyloxy-cholesten-(2)
作者:Ch. Tamm、R. Albrecht
DOI:10.1002/hlca.19590420646
日期:——
Reaktionsprodukte: Cholestadien-(1,3) (IX) (Elimination), 3α-Hydroxycholesten-(l) (VII) (Substitution) und einen mit VII isomeren ungesättigten Alkohol, der nicht aufgeklärt wurde. IX wurde auch durch Pyrolyse von IV erhalten. Analog lieferte 3α-Benzoyloxy-cholesten-(l) (VI) mit Al2O3 3β-Hydroxycholesten-(1) (II) als Hauptprodukt.
3β-苯甲酰氧基胆甾醇-(l)(IV)在用“中性”活化的Al 2 O 3处理后产生了三种新的反应产物:胆甾二烯- (1,3)(IX)(消除),3α-羟基胆甾烯醇-(l )(VII)(取代)和未明确说明的VII醇异构体。IX也通过IV的热解获得。类似地,具有Al 2 O 3的3α-苯甲酰氧基胆甾烯-(1)(VI)给出了3β-羟基胆甾烯-(1)(II)作为主要产物。
Steroids and Walden inversion. Part LXII. The chlorination of 5α-cholestan-1-one
作者:C. W. Shoppee、S. C. Sharma
DOI:10.1039/j39680000245
日期:——
Monochlorination of 5α-cholestan-1-one is slow and yields 28% of the axial 2β-chloro-ketone and 32% of the equatorial 2α-chloro-ketone under conditions in which the 2β-chloro-ketone undergoes inversion to the extent of 49%; the values, 28 and 32%, take account of this transformation caused by acid-catalysed enolisation. Monochlorination of the axial 2β-chloro-ketone to give the 2,2-dichloro-ketone
Steroids and Walden inversion. Part LX. Some reactions of the epimeric 5α-cholestan-1-ols and the solvolysis of their toluene-p-sulphonates
作者:C. W. Shoppee、Ruth E. Lack、S. C. Sharma、Lorraine R. Smith
DOI:10.1039/j39670001155
日期:——
gives a similar mixture of the same three olefins and some 5α-cholestan-1α-ol. 5α-Cholestan-1β-ol with the same reagents gives a single crystalline olefin, 9aζ A-nor-B-homo-19-norcholest-5(10)-ene, whilst solvolysis of 5α-cholestan-1β-yl toluene-p-sulphonate yields mainly the non-crystalline 9a-methylene-A-nor-B-homo-19-nor-5α-cholestane, and some 5α-cholestan-1β-ol.
5α-Cholestan-1a-ol与五氯化磷或亚硫酰氯形成5α-胆甾1-烯,1β-甲基-19-norcholest-5(10)-烯和1β-甲基-19-nor-5α的混合物-cholest-9-ene,同时在缓冲的丙酮水溶液中在65°下溶剂化5α-cholestan-1α-甲苯基对苯二甲酸磺酸盐时,得到的是相同的三种烯烃和一些5α-cholestan-1α-ol的相似混合物。使用相同试剂的5α-Cholestan-1β-ol可得到单晶烯烃9aζA-nor-B-homo-19-norcholest-5(10)-烯,同时溶剂化5α-cholestan-1β-yl甲苯-p -磺酸盐主要产生非晶的9a-亚甲基-A -nor- B -homo-19-nor-5α-胆甾烷和一些5α-胆甾烷-1β-ol。
Photoinduced molecular transformations. Part 133. New photoinduced deconjugation of steroidal α,β-unsaturated cyclic ketone oxime into the β,γ-unsaturated isomer involving stereospecific proton transfer
photo-Beckmann rearrangement was formed. Deuterium-labelling studies on the photoreactions of 1-methyl-5α-cholest-1-en-3-one oxime established that either a proton or a deuteron is stereospecifically introduced at the 2α-position of the steroidal oxime in this photodeconjugation. A pathway which involves the sterospecific addition of either a proton or deuteron to the photogenerated, twisted double bond of