Cl.C(OCC)(=O)C.[CH2:8]([O:15][C:16]([NH:18][C@H:19]1[CH2:24][CH2:23][N:22]([C:25](OC(C)(C)C)=[O:26])[CH2:21][C@H:20]1[O:32][CH3:33])=[O:17])[C:9]1[CH:14]=[CH:13][CH:12]=[CH:11][CH:10]=1.C[Si]([N:38]=C=O)(C)C.CO>C(OCC)(=O)C>[C:25]([N:22]1[CH2:23][CH2:24][C@H:19]([NH:18][C:16](=[O:17])[O:15][CH2:8][C:9]2[CH:14]=[CH:13][CH:12]=[CH:11][CH:10]=2)[C@H:20]([O:32][CH3:33])[CH2:21]1)(=[O:26])[NH2:38]
A 4 N hydrochloric acid/ethyl acetate solution (30 ml, 120 mmol) was added to a solution of tert-butyl cis(±)-4-{[(benzyloxy)carbonyl]amino}-3-methoxypiperidine-1-carboxylate obtained in Example (103a) in ethyl acetate (10 mL). The mixture was stirred for 45 minutes and the solvent was evaporated under reduced pressure. The residue was diluted with dichloromethane, washed with a 1 N aqueous sodium hydroxide solution and brine, dried over anhydrous magnesium sulfate, and then concentrated under reduced pressure. Trimethylsilyl isocyanate (0.86 g, 7.5 mmol) was added to the resulting residue, and the mixture was stirred at room temperature for 15 hours. Methanol (1 mL) was added, followed by stirring for 30 minutes. The precipitated solid was filtered off and washed with dichloromethane to obtain 1.44 g of the title compound as a colorless solid (81%).
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