title: Synthesis of 4- and 16 alpha-hydroxylated equine estrogens.
abstract: 4-Hydroxyequilin, 4-hydroxyequilenin, and 16 alpha-hydroxyequilenin were synthesized as authentic specimens for the metabolic studies of equine estrogens. The synthetic route leading to the 4-hydroxylated compounds was started from o-vanillin, which was transformed into the beta-ketosulfoxide (2b) by sequential multistep reactions. This was converted to the alpha,beta-unsaturated ketone (3) as Michael acceptor. Condensation of 3 with 2-methylcyclopentane-1,3-dione, followed by ring closure with methanesulfonic acid provided the cyclized estrapentaene (5). Several oxidoreduction reactions were then performed to give the desired compounds. Preparation of 16 alpha-hydroxyequilenin was attained by reductive cleavage of the 16 alpha,17 alpha-epoxide formed from equilenin.
authors.affiliation: Faculty of Pharmaceutical Sciences, Higashi-Nippon-Gakuen University, Hokkaido, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Ikegawa
authors.forename: T
authors.initials: T
authors.lastname: Kurosawa
authors.forename: M
authors.initials: M
authors.lastname: Tohma
mesh_terms: D015068:17-Ketosteroids / Q000138:chemical synthesis*; D001547:Benzaldehydes; D055598:Chemical Phenomena; D002621:Chemistry; D004855:Equilenin / Q000031:analogs & derivatives / Q000138:chemical synthesis*; D004857:Equilin / Q000031:analogs & derivatives / Q000138:chemical synthesis*; D006900:Hydroxylation; D015394:Molecular Structure; D010084:Oxidation-Reduction
chemical_list: D015068:17-Ketosteroids; D001547:Benzaldehydes; C060843:2-vanillin; D004857:Equilin; C065251:16-hydroxy-equilenin; C065250:4-hydroxy-equilenin; C065248:4-hydroxy-equilin; C100058:vanillin; D004855:Equilenin