[CH3:1][O:2][C:3](=[O:21])[C:4]([CH3:20])([CH3:19])[CH2:5][N:6]1[CH2:11][CH2:10][N:9](C(OC(C)(C)C)=O)[CH2:8][CH2:7]1.C(O)(C(F)(F)F)=O>C(Cl)Cl>[CH3:19][C:4]([CH3:20])([CH2:5][N:6]1[CH2:11][CH2:10][NH:9][CH2:8][CH2:7]1)[C:3]([O:2][CH3:1])=[O:21]A solution of 568 (1.137 g, 3.79 mmol) and TFA (15 ml) in DCM (30 ml) was stirred at rt for 2.5 h. The reaction mixture was concentrated (azeotropes with DCM), diluted with water, stirred for 1 h, and the pH was adjusted to around 9-10 with 1N NaOH. The alkaline solution was extracted with DCM. The extract was dried over anhydrous magnesium sulfate, filtered, concentrated and dried under high vacuum to afford the desired product 569 (667 mg, 3.33 mmol, 88% yield) as a pale-yellow viscous liquid. The crude material was used in the next step without any further purification. MS (z): 201.1 (M+H).
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