title: Anodic electrochemical oxidation of cholic acid.
abstract: Regioselectivity in the anodic electrochemical oxidation of cholic acid with different anodes is described. The oxidation with PbO(2) anode affords the dehydrocholic acid in quantitative yield after 22 h. 3alpha,12alpha-Dihydroxy-7-oxo-5beta-cholan-24-oic acid (59%) and 3alpha-hydroxy-7,12-dioxo-5beta-cholan-24-oic acid (51%) are obtained stopping the reaction at lower time. The rate of the OH-oxidation is C7 > C12 > C3. The electro-oxidation with platinum foil anode gives selectively the 7-ketocholic acid in 40% yield. On the other hand, the graphite plate anode, varying the reaction conditions, produces selectively the dehydrocholic acid in quantitative yield or the 3alpha,12alpha-dihydroxy-7-oxo-5beta-cholan-24-oic acid (96%) while the 3alpha,7alpha-dihydroxy-12-oxo-5beta-cholan-24-oic acid (34%) is obtained together with the other oxo acids.
authors.affiliation: Dipartimento di Chimica, Università di Ferrara, Via L. Borsari 46, I-44100, Ferrara, Italy. mda@dns.unife.it
authors.forename: A
authors.initials: A
authors.lastname: Medici
authors.forename: P
authors.initials: P
authors.lastname: Pedrini
authors.forename: A
authors.initials: A
authors.lastname: De Battisti
authors.forename: G
authors.initials: G
authors.lastname: Fantin
authors.forename: M
authors.initials: M
authors.lastname: Fogagnolo
authors.forename: A
authors.initials: A
authors.lastname: Guerrini
mesh_terms: D019826:Cholic Acid / Q000737:chemistry*; D002849:Chromatography, Gas; D004563:Electrochemistry; D004566:Electrodes; D010084:Oxidation-Reduction
chemical_list: D019826:Cholic Acid