Highly efficient synthesis of steroid-17-spiro-5'-oxazolidine-2',4'-diones from 17-keto steroids

Article abstract of DOI:10.1016/0039-128X(90)90088-S

Spiro-2',3,4'-trione 8a and spiro-2',3,4',11-tetraone 8b, two potentially bioactive spiranes, were prepared from the parent 17-ketones in four steps (64percent and 49.5percent 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 alkylchlorocarbonates.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 17α-hydroxy-17carboxyesters and 17α-hydroxy-17-carboxamides is described.Attempts to synthesize the title compounds from these products were unsuccessful.