C(OC([N:6]1[CH:11]2[CH2:12][CH2:13][CH:7]1[CH2:8][C:9](=[C:14]1[C:27]3[CH:26]=[CH:25][C:24]([C:28](=[O:34])[N:29]([CH2:32][CH3:33])[CH2:30][CH3:31])=[CH:23][C:22]=3[O:21][C:20]3[C:15]1=[CH:16][CH:17]=[CH:18][CH:19]=3)[CH2:10]2)=O)C.Br>C(O)(=O)C>[CH2:32]([N:29]([CH2:30][CH3:31])[C:28]([C:24]1[CH:25]=[CH:26][C:27]2[C:14](=[C:9]3[CH2:10][CH:11]4[NH:6][CH:7]([CH2:13][CH2:12]4)[CH2:8]3)[C:15]3[C:20]([O:21][C:22]=2[CH:23]=1)=[CH:19][CH:18]=[CH:17][CH:16]=3)=[O:34])[CH3:33]A sample of compound 8a (16.0 g, 34.8 mmol) was dissolved in 35 mL acetic acid and 100 mL of 30% HBr in acetic acid was added to the reaction under Argon before heating on a steam bath for 1 h. The reaction was cooled, added to ice cold NaOH and extracted with CH2Cl2. The combined organics were washed with brine and dried over potassium carbonate. Evaporation of the solvent provided 12 g of crude Compound 10a, which was purified by column chromatography with 7% 2 N NH3 in methanol/93% CH2Cl2. to give 7.66 g (19.7 mmol) of Compound 10a. MS m/z=389.3 (M+1); 1H NMR 300 MHz (CDCl3) δ 1.1-1.4 (m, 6H), 1.7 (m, 2H), 2.7-3.0 (m, 4H), 3.4 (br s, 4H), 3.5-3.7 (m, 4H), 7.0-7.3 (m, 7H).
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