Chenodeoxycholic acid is very important in the preparation of UDCA, there are three sources of UDCA: ① Drainage of bile bile, which is the current method of condemnation. ② Chemical synthesis, many scholars have explored, looking for a simple and feasible chemical pathways. ③ Biotransformation method, it has been reported that CDCA in chicken bile can be transformed into UDCA by the transformation of Clostridium heterophylla. Chenodeoxycholic acid plays an important role in both chemical synthesis and biotransformation.
Artificial drainage of bile bile is the main method of obtaining UDCA, and the formation of industrial scale, this method not only harm the conservation and health of bear animals, while studies suggest that in the artificial bile bear bile, chenodeoxycholic acid content is higher than natural bear bile, the more frequent the drainage, the higher the content of CDCA, the quality and pharmacological effects of drainage bear bile can not be guaranteed. In the synthesis of ursodeoxycholic acid, chenodeoxycholic acid is an important intermediate, but also an important raw material, reported to chenodeoxycholic acid, and then synthesized to synthesize UDCA, Zhuang Zhiping reported using NBS or Jones reagent to oxidize methyl goose deoxycholic acid, and then in the oxidation of 3α-5β-hydroxy-7-carbonyl cholic acid (7K-LCA) N-butanol with metal sodium, nickel dioxide reduction, the total yield of about 42%. Zhang Guoping reported using NBS in acetone and water oxidation of CDCA, made 7K-LCA, the yield of up to 89%. European patent reports 7K-LCA with metal nickel in the presence of KOCMe3, Me2CHOH under normal pressure at 40 ℃ hydrogenation UDCA, yield up to 95%.
Japanese Patent Report 7K-LCA was heated to 100 ° C for 5 hours in an autoclave in the presence of NaOH, BuOH and Pd /C to give 88.2% of UDCA. The Japanese patent also reported that 7K-LCA was treated with KOH in acetone and refluxed for 2 h, and 99.5% of the chrysanthemic acid-containing UDCA mixture was reacted with H2-RaneyNi at 80 ° C at 419 x 105 Pa for 3.5 h to give a reduction yield of 97.7% The There are reports of his synthesis of raw materials UDCA, are based on CDCA as an intermediate. Biotransformation synthesis of UDCA, still with CDCA as the main raw material, is still in the laboratory stage.