[CH3:1][O:2][C:3]([C@@H:5]1[CH2:9][C@H:8]([NH:10][C:11]([O:13][CH2:14][C:15]2[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=2)=[O:12])[CH2:7][N:6]1C(OC(C)(C)C)=O)=[O:4]>Cl.O1CCOCC1>[CH3:1][O:2][C:3]([C@@H:5]1[CH2:9][C@H:8]([NH:10][C:11]([O:13][CH2:14][C:15]2[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=2)=[O:12])[CH2:7][NH:6]1)=[O:4](2S,4S)-4-Benzyloxycarbonylaminopyrrolidine-1,2-dicarboxylic acid 1-t-butyl ester 2-methyl ester (10.4 g, 28 mmol) was dissolved in a 4M solution of HCl in 1,4-dioxane. The solution was stirred at room temperature for 3 hours and then evaporated. The residue was partitioned between EtOAc (200 mL) and 1M NaOH (100 mL), the layers separated and the aqueous layer re-extracted with EtOAc (100 mL). The combined organics were washed with saturated aqueous NaCl (100 mL), dried over Na2SO4, and evaporated to afford the title compound (5.4 g, 19 mmol) as a white solid, which was used without further purification. MS m/z: [M+H]+ calcd for C1-4H18N2O4, 278.3. found 279.2.
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