Method for separation and purification of LCZ696 intermediate diastereoisomer

A method for separation and purification of LCZ696 intermediate diastereoisomer includes the following steps: (1) placing the mixture of the diastereoisomer (I-a) and (I-b) in an organic solvent untilthe mixture is completely dissolved, cooling to 0-10 DEG C, recrystallizing until the crystal is stable, filtering, taking a filter cake, and drying to obtain a product mixture, and (2) taking the filtrate, removing the solvent under reduced pressure, and drying the solute to obtain an impurity mixture. The method for separation and purification can efficiently and conveniently separate and purify the diastereomers (I-a) and(I-b) and the purity of the resulting product mixture (I-a) is as high as 95 percent, which can be directly used for preparing a high-purity Sacubitril intermediate to finally synthesize LCZ696 so as to ensure the product quality. 种LCZ696中间体非对映异构体的分离纯化方法，具有以下步骤：1)将任意混合比的非对映异构体(Ⅰ-a)、(Ⅰ-b)的混合物，置于有机溶剂中至溶解完全，降温至0-10℃重结晶，至晶体稳定，过滤，取滤饼，经烘干得到产品混合物；2)取滤液，减压除去溶剂，溶质经烘干得到杂质混合物。本发明分离纯化方法，可高效、方便的分离纯化非对映异构体(