Abstract: The present application relates to a method (I) for preparing a brivaracetam intermediate, comprising the steps of dissolving the compound represented by B-P and 1S,2S-diphenylethylenediamine in a solvent for resolution, crystallizing, filtering, and recrystallizing to obtain the compound represented by B-Q, which is then converted to the brivaracetam intermediate represented by B-R. This method can effectively resolve the compound represented by B-P. The present application also provides a method for preparing brivaracetam using the compound represented by B-R. The method can separate the effective components only through simple steps such as extraction, washing, drying, and concentration without requiring use of chiral chromatography column to separate isomers in the preparation process, and thus the separation process is simple, greatly reducing the production cost of brivaracetam.

Abstract: Disclosed is a method for preparing a brivaracetam intermediate shown in formula B-R, comprising: reacting a compound shown in formula B-P and a resolving agent to prepare a compound shown in formula B-Q; and converting the compound shown in formula B-Q into the brivaracetam intermediate shown in formula B-R, wherein the resolving agent is a (1S,2S)-(+)-1,2-diaminocyclohexane compound. Also provided is a method for preparing brivaracetam. According to the method, a mixture of two diastereoisomers of (S)-2-3-propylpyrrolidine-1-yl butyric acid can be conveniently and effectively resolved, and the use of a chiral HPLC column is avoided, thereby greatly shortening the process time, simplifying the operation, reducing the process cost, and facilitating industrial production and enviormental protection.

Abstract: The present application relates to a method (I) for preparing a brivaracetam intermediate, comprising the steps of dissolving the compound represented by B-P and 1S,2S-diphenylethylenediamine in a solvent for resolution, crystallizing, filtering, and recrystallizing to obtain the compound represented by B-Q, which is then converted to the brivaracetam intermediate represented by B-R. This method can effectively resolve the compound represented by B-P. The present application also provides a method for preparing brivaracetam using the compound represented by B-R. The method can separate the effective components only through simple steps such as extraction, washing, drying, and concentration without requiring use of chiral chromatography column to separate isomers in the preparation process, and thus the separation process is simple, greatly reducing the production cost of brivaracetam.