| 摘要 |
The present invention describes a process for producing ezetimibe (EZT) from a protected compound, including a step of deprotecting the 4-(p-hydroxyphenyl) protection group by catalytic hydrogenation, wherein the catalyst is used in an amount of 0.7 wt.-% or lower, relative to the weight of the compound used for the deprotection reaction. After carrying out a step of deprotection reaction, the process preferably comprises: (a) the reaction product is dissolved or extracted in ethyl acetate, and (b) the ethyl acetate solution is washed with an aqueous salt solution. The invention further describes a process for obtaining pure EZT, wherein raw EZT is dissolved in a solvent at a concentration of lower than 0.1 g/ml, and a crystallization step is carried out from this solution. These measures, respectively alone and particularly in combination contribute to attain ezetimibe (EZT) free of critical impurities described herein, and thus to use exceptionally pure ezetimibe (EZT) to be formulated into a pharmaceutical composition together with a pharmaceutically acceptable carrier or excipient.
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