title: Highly efficient synthesis of steroid-17-spiro-5'-oxazolidine-2',4'-diones from 17-keto steroids.
abstract: Spiro[androst-4-en-17 alpha,5'-oxazolidine]-2',3,4'-trione 8a and spiro[androst-4-en-17 alpha,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 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 17 alpha-hydroxy-17-carboxyesters and 17 alpha-hydroxy-17-carboxamides is described. Attempts to synthesize the title compounds from these products were unsuccessful.
authors.affiliation: Cattedra di Chimica Medica, Facoltà di Medicina e Chirurgia, Florence, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Ginanneschi
authors.forename: M
authors.initials: M
authors.lastname: Chelli
authors.forename: A
authors.initials: A
authors.lastname: Papini
authors.forename: G
authors.initials: G
authors.lastname: Rapi
mesh_terms: D015068:17-Ketosteroids; D015394:Molecular Structure; D010080:Oxazoles / Q000138:chemical synthesis*; D013141:Spiro Compounds / Q000138:chemical synthesis*; D013256:Steroids / Q000138:chemical synthesis*
chemical_list: D015068:17-Ketosteroids; D010080:Oxazoles; D013141:Spiro Compounds; D013256:Steroids