Regioselectivity in the anodic electrochemical oxidation of cholic acid with different anodes is described. The oxidation with PbO2 anode affords the dehydrocholic acid in quantitative yield after 22 h. 3α,12α-Dihydroxy-7-oxo-5β-cholan-24-oic acid (59%) and 3α-hydroxy-7,12-dioxo-5β-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 3α,12α-dihydroxy-7-oxo-5β-cholan-24-oic acid (96%) while the 3α,7α-dihydroxy-12-oxo-5β-cholan-24-oic acid (34%) is obtained together with the other oxo acids. Copyright © 2001 Elsevier Science Inc.
Anodic electrochemical oxidation of cholic acid
Medici A.;Pedrini P.;De Battisti A.;Fantin G.;Fogagnolo M.;Guerrini A.
2001
Abstract
Regioselectivity in the anodic electrochemical oxidation of cholic acid with different anodes is described. The oxidation with PbO2 anode affords the dehydrocholic acid in quantitative yield after 22 h. 3α,12α-Dihydroxy-7-oxo-5β-cholan-24-oic acid (59%) and 3α-hydroxy-7,12-dioxo-5β-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 3α,12α-dihydroxy-7-oxo-5β-cholan-24-oic acid (96%) while the 3α,7α-dihydroxy-12-oxo-5β-cholan-24-oic acid (34%) is obtained together with the other oxo acids. Copyright © 2001 Elsevier Science Inc.| File | Dimensione | Formato | |
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