title: Potential bile acid metabolites. 25. Synthesis and chemical properties of stereoisomeric 3alpha,7alpha,16- and 3alpha,7alpha,15-trihydroxy-5beta-cholan-24-oic acids.
abstract: Epimeric 3alpha,7alpha,16- and 3alpha,7alpha,15-trihydroxy-5beta-cholan-24-oic acids and some related compounds were synthesized from chenodeoxycholic acid (CDCA) and ursodeoxycholic acid (UDCA), respectively. The key reaction involved one-step remote oxyfunctionalization of unactivated methine carbons at C-17 of CDCA and at C-14 of UDCA as their methyl ester-peracetate derivatives with dimethyldioxirane (DMDO). After dehydration of the resulting 17alpha- and 14alpha-hydroxy derivatives with POCl(3) or conc. H(2)SO(4), the respective Delta(16)- and Delta(14)-unsaturated products were subjected to hydration via hydroboration followed by oxidation to yield the 3,7,16- and 3,7,15-triketones, respectively. Stereoselective reduction of the respective triketones with tert-butylamine-borane complex afforded the epimeric 3alpha,7alpha,16- or 3alpha,7alpha,15-trihydroxy derivatives exclusively. A facile formation of the corresponding epsilon-lactones between the side chain carboxyl group at C-24 and the 16alpha- (or 16beta-) hydroxyl group in bile acids is also clarified.
authors.affiliation: College of Humanities and Sciences, Nihon University, Japan. takaiida@chs.nihon-u.ac.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Iida
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hikosaka
authors.forename: Genta
authors.initials: G
authors.lastname: Kakiyama
authors.forename: Keisuke
authors.initials: K
authors.lastname: Shiraishi
authors.forename: Claudio D
authors.initials: CD
authors.lastname: Schteingart
authors.forename: Lee R
authors.initials: LR
authors.lastname: Hagey
authors.forename: Huong-Thu
authors.initials: HT
authors.lastname: Ton-Nu
authors.forename: Alan F
authors.initials: AF
authors.lastname: Hofmann
authors.forename: Nariyasu
authors.initials: N
authors.lastname: Mano
authors.forename: Junichi
authors.initials: J
authors.lastname: Goto
authors.forename: Toshio
authors.initials: T
authors.lastname: Nambara
mesh_terms: D001647:Bile Acids and Salts / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism*; D002635:Chenodeoxycholic Acid / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism; D013237:Stereoisomerism
chemical_list: D001647:Bile Acids and Salts; D002635:Chenodeoxycholic Acid