2458-53-9Relevant articles and documents
Sterochemical Aspects of Acid-Catalyzed Cyclopropane Ring-Opening Reactions. A Stereospecific Pathway to Crinosterol and Brassicasterol
Lang, Robert W.,Djerassi, Carl
, p. 407 - 418 (2007/10/02)
It is shown that the acid-catalyzed ring-opening of the two diastereoisomeric 23,24-methylenecholosterols 3 and 5 on treatment with gaseous HCl in acetic acid leads sterospecifically to the naturally occuring crinosterol (4) and brassicasterol (6), respectively (Scheme 1).This isomerization can be viewed as a biomimetic model of an in vivo methylation process of the type already known in plant sterol metabolism (cf. cycloeucalenol --> obtusifoliol, 1-->2).The synthetic application of this method provides a convenient labelling of sterol side chain for tracer experiments.The mechanistic features of the reaction with respect to its particular stereospecificity are discussed.
A Simple Method for the Reduction of the 7,8-Double Bond of Steroidal 5,7-Dienes
Anastasia, Mario,Ciuffreda, Pierangela,Fiecchi, Alberto
, p. 1169 - 1170 (2007/10/02)
1,4-Cycloadducts of various steroidal 5,7-dienes and 4-phenyl-1,2,4-triazoline-3,5-dione gave a separable mixture (3 : 2) of the corresponding Δ5- and Δ7-sterols in good yield when treated with lithium dissolved in refluxing ethylamine.