C(OC([N:8]1[CH2:11][CH2:10][C@@:9]1([C:13](=[O:30])[N:14]([CH2:22][C:23]1[CH:28]=[CH:27][CH:26]=[C:25]([Cl:29])[CH:24]=1)[CH2:15][CH2:16][CH2:17][C:18]([O:20][CH3:21])=[O:19])[CH3:12])=O)(C)(C)C.Cl>O1CCOCC1>[ClH:29].[CH3:21][O:20][C:18](=[O:19])[CH2:17][CH2:16][CH2:15][N:14]([CH2:22][C:23]1[CH:28]=[CH:27][CH:26]=[C:25]([Cl:29])[CH:24]=1)[C:13]([C@@:9]1([CH3:12])[CH2:10][CH2:11][NH:8]1)=[O:30]To a solution of (R)-2-[(3-chloro-benzyl)-(3-methoxycarbonyl-propyl)-carbamoyl]-2-methyl-azetidine-1-carboxylic acid tert-butyl ester, Intermediate 175 (17.6 g, 1 eq.) in 200 mL of dioxane under nitrogen was added a solution of HCl (4N) in dioxane (50 mL, 5 eq.). The reaction was stirred for 16 h at 20° C., then concentrated under reduced pressure. The crude was solubilised in DCM, poured into Et2O and the resulting solid was filtered, washed with Et2O and pentane and dried to afford 4-[(3-chloro-benzyl)-((R)-2-methyl-azetidine-2-carbonyl)-amino]-butyric acid methyl ester hydrochloride (12.5 g, yield=81%).
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