Method for preparing tauro ursodesoxy cholic acid

The invention discloses a method for preparing tauro ursodesoxy cholic acid. The synthetic method comprises the following steps: a step (1) of adding ursodeoxycholic acid and phenolic compounds into chloralkane organic solvent at room temperature, performing cooling to 10-20 DEG C, adding a condensing agent; after the condensing agent is added dropwise, reacting completely at 5-45 DEG C, performing filtration and then concentrating filtrate to obtain a crude product, performing recrystallization and then obtaining high-finished product ursodesoxycholic acid phenolic ester as shown in a formula (II); a step (2) of adding the high-finished product ursodesoxycholic acid phenolic ester and taurine salt into an organic alcohol solvent to undergo the reaction completely, lowering the temperature to room temperature and then performing filtration, dissolving filter cake in water, using acid to adjust the pH to 1.0-3.0, and performing stirring and crystallization to obtain tauro ursodesoxy cholic acid as shown in a formula (I). The synthetic method is low cost, simple to operate, controllable and high in product yield and purity, an isomer impurity taurochenodeoxycholic acid of tauro ursodesoxy cholic acid can be controlled well, and the method is suitable for industrial production.