title: Hydroxylation and epimerization of ecdysteroids in alkaline media: stereoselective synthesis of 9α-hydroxy-5α-ecdysteroids.
abstract: Autoxidation of diacetonides of 20-hydroxyecdysone and ponasterone A under treatment with excess of NaOH in methanol leads to the formation of 9α-hydroxy-5α-ecdysteroids previously not described. Their structures have been determined by detailed NMR analysis. Catalytic hydrogenation (Pd-C, MeOH-MeONa) of hydroxylated ecdysteroids affords the 7,8α-dihydro-9α-hydroxy-5α-ecdysteroids.
authors.affiliation: Institute of Petrochemistry and Catalysis, Russian Academy of Science, Laboratory of Organic Synthesis, Prospekt Oktyabrya 141, 450075 Ufa, Russian Federation. Electronic address: rimasavchenko@mail.ru.
authors.forename: Rimma G
authors.initials: RG
authors.lastname: Savchenko
authors.affiliation: Institute of Petrochemistry and Catalysis, Russian Academy of Science, Laboratory of Organic Synthesis, Prospekt Oktyabrya 141, 450075 Ufa, Russian Federation.
authors.forename: Svetlana A
authors.initials: SA
authors.lastname: Kostyleva
authors.affiliation: N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospekt 47, 119991 Moscow, Russian Federation.
authors.forename: Vadim V
authors.initials: VV
authors.lastname: Kachala
authors.affiliation: Institute of Petrochemistry and Catalysis, Russian Academy of Science, Laboratory of Organic Synthesis, Prospekt Oktyabrya 141, 450075 Ufa, Russian Federation.
authors.forename: Leonard M
authors.initials: LM
authors.lastname: Khalilov
authors.affiliation: Institute of Petrochemistry and Catalysis, Russian Academy of Science, Laboratory of Organic Synthesis, Prospekt Oktyabrya 141, 450075 Ufa, Russian Federation.
authors.forename: Victor N
authors.initials: VN
authors.lastname: Odinokov
mesh_terms: D060326:Chemistry Techniques, Synthetic; D026461:Ecdysteroids / Q000138:chemical synthesis* / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D006900:Hydroxylation; D000432:Methanol / Q000737:chemistry; D012972:Sodium Hydroxide / Q000737:chemistry; D013237:Stereoisomerism; D013379:Substrate Specificity
chemical_list: D026461:Ecdysteroids; D012972:Sodium Hydroxide; D000432:Methanol
keywords: Autoxidation; Ecdysteroids; Epimerization; Hydrogenation