Benazepril hydrochloride is prepared through the following steps:
Step 1: Preparation of (R)-ethyl 2-hydroxy-4-phenylbutyrate using ethyl 2-oxo-4-phenylbutyrate as a raw material and cinchonidine as a chiral ligand through asymmetric catalytic hydrogenation under high pressure.
Step 2: The intermediate obtained from step 1 reacts with p-nitrobenzenesulfonyl chloride or trifluoromethanesulfonic anhydride to obtain the corresponding sulfonate.
Step 3: The sulfonate obtained from step 2 undergoes nucleophilic substitution and salt hydrolysis with (3S)-3-amino-2,3,4,5-tetrahydro-2-oxo-1H-benzazepine-1-tert-butyl acetate to obtain benazepril hydrochloride.
This procedure has been described in detail in documents such as
CN110835319A, US4785089, WO02076375, EP206993, and CN105061312.