title: Preparation of (25R)- and (25S)-26-functionalized steroids as tools for biosynthetic studies of cholic acids.
abstract: A new synthesis of both epimeric forms of 26-cholestanoic acids and 26-alcohols containing a 3beta-hydroxy-Delta(5)- or a Delta(4)-3-keto-functionality in ring A is described starting from stigmasterol or (20S)-3beta-acetoxy-pregn-5-en-20-carboxylic acid. The obtained compounds are useful as standards for studies of cholic acids. Construction of the side chain was achieved by linkage of steroidal 23-iodides to sulfones prepared from (2R)- and (2S)-3-hydroxy-2-methylpropanoates. Oxidation of intermediate 26-alcohols into the corresponding carboxylic acids ensuring preservation of stereochemistry at C-25 and functional groups in the cyclic part was achieved with sodium chlorite catalyzed by TEMPO and bleach.
authors.affiliation: Laboratory of Chemistry of Steroids, Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus, Kuprevich Str. 5/2, 220141 Minsk, Belarus. khripach@iboch.bas-net.by
authors.forename: Vladimir A
authors.initials: VA
authors.lastname: Khripach
authors.forename: Vladimir N
authors.initials: VN
authors.lastname: Zhabinskii
authors.forename: Olga V
authors.initials: OV
authors.lastname: Konstantinova
authors.forename: Natalya B
authors.initials: NB
authors.lastname: Khripach
authors.forename: Alexey V
authors.initials: AV
authors.lastname: Antonchick
authors.forename: Andrey P
authors.initials: AP
authors.lastname: Antonchick
authors.forename: Bernd
authors.initials: B
authors.lastname: Schneider
mesh_terms: D000438:Alcohols / Q000737:chemistry; D002247:Carbon Isotopes; D002264:Carboxylic Acids / Q000737:chemistry; D002384:Catalysis; D002778:Cholestanones / Q000138:chemical synthesis* / Q000737:chemistry; D002793:Cholic Acids / Q000096:biosynthesis*; D002855:Chromatography, Thin Layer; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010084:Oxidation-Reduction; D011278:Pregnanes / Q000737:chemistry; D013237:Stereoisomerism; D013256:Steroids / Q000737:chemistry; D013265:Stigmasterol / Q000737:chemistry; D013450:Sulfones / Q000737:chemistry
chemical_list: D000438:Alcohols; D002247:Carbon Isotopes; D002264:Carboxylic Acids; D002778:Cholestanones; D002793:Cholic Acids; D011278:Pregnanes; D013256:Steroids; D013450:Sulfones; D013265:Stigmasterol