Δ 2,4,6 -Cholestatrien。BeiBrug zum机制的HBr-Abspaltung aus 7-溴-胆固醇基苯甲酸酯
摘要:
1.孛DER的HBr-Abspaltung AUS7β-维奇-cholesterylbenzoat wurde ALS Nebenprodukt EIN三烯isoliert,DEM sehr wahrscheinlich死Formel EINESΔ 2,4,6- -Cholestatriens zukommt。
在胆固醇与 BPO 在四氯化碳中的反应中分离出了胆甾烯-2,4,6-三烯(I)、3,3'-双胆甾烯-2,4,6,5'-四烯(II)和苯甲酸。据推测,最初形成的 I 会进一步发生自由基反应,生成 II。还推测形成物质 I 和 II 的一系列反应应该是通过 BPO 热解胆固醇引起的苯氧自由基加成反应,从而导致自由基脱水和自由基脱氢。生成物 I 和 II 应通过形成相应的阳离子或羰离子而被染成蓝色。研究发现,这种颜色反应对具有 5-烯-3-醇或其酯结构的类固醇具有特异性,因此可用于检测和测定这些类固醇。
Comparative cotton effects of steroidal 2,4-dienes and related trienes: origin of the folded conformation in levopimaric acid
作者:Albert W. Burgstahler、Jacek Gawronski、Theodore F. Niemann、Benjamin A. Feinberg
DOI:10.1039/c29710000121
日期:——
The decreased intensity of the positive Cotton effects of a 9α-methyl- and a 19-nor-steroidal 2,4-diene compared to those of other steroidal 2,4-dienes suggests that the peculiar B/C folded conformation in levopimaricacid (negative Cotton effect) is caused by relief of a 1,3-diaxial repulsion between the C-10 angular methyl group and the 11β-hydrogen, probably enhanced by C-4 methyl buttressing, which
Use of a Continuous Nephelometer to Measure Personal Exposure to Particles During the U.S. Environmental Protection Agency Baltimore and Fresno Panel Studies
作者:Cynthia Howard-Reed、Anne W. Rea、Maria J. Zufall、Janet M. Burke、Ron W. Williams、Jack C. Suggs、Linda S. Sheldon、Debra Walsh、Richard Kwok
DOI:10.1080/10473289.2000.10464150
日期:2000.7
population exposurestudies, personalexposure to PM is typically measured as a 12- to 24-hr integrated mass concentration. To better understand short-term variation in personal PM exposure, continuous (1-min averaging time) nephelometers were worn by 15 participants as part of two U.S.EnvironmentalProtectionAgency (EPA) longitudinal PM exposurestudies conducted in Baltimore County, MD, and Fresno, CA
The Anthrasteroid Rearrangement. IV. The Preparation of Several New Anthrasteroids and Some Observations on the Dehydrobromination of 7-Bromo-Δ<sup>5</sup>-steroids<sup>1</sup>
作者:William R. Nes、Robert B. Kostic、Erich Mosettig
DOI:10.1021/ja01583a051
日期:1956.1
Frederiksen; Liisberg, Chemische Berichte, 1955, vol. 88, p. 684