Highly efficient synthesis of steroid-17-spiro-5'-oxazolidine-2', 4' -diones from 17-keto steroids
作者:Mauro Ginanneschi、Mario Chelli、Annamaria Papini、Gianfranco Rapi
DOI:10.1016/0039-128x(90)90088-s
日期:1990.11
Spiro[androst-4-en-17alpha, 5'-oxazolidine]-2', 3, 4'-trione 8-alpha and spiro]androst-4-en-17alpha, 5'-oxazolidine[-2', 3, 4', 11-tetraone 8b, two potentially bioactive spiranes, were prepared from the parent 17-ketones in four steps (64% and 49.5% yield, respectively). The key intermediates were the hydroxyimidates 5a and 5b, which easily underwent cyclization to the corresponding spirooxazolinone 4'-enol ethers when treated with alkychlorocarbonates. The respective N-amyl derivatives of the spiranes 8a and 8b were obtained with n-pentyl bromide in the presence of KF. A new method for the synthesis of steroid 17-alpha-hydroxy-17-carboxyesters and 17-alpha-hydroxy-17-carboxamides is described. Attempts to synthesize the title compounds from these products were unsuccessful.