C([O:8][C:9](=[O:33])[C:10]1[CH:15]=[C:14]([O:16][CH2:17][C:18]2[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=2)[C:13]([Br:24])=[C:12]([O:25][CH2:26][C:27]2[CH:32]=[CH:31][CH:30]=[CH:29][CH:28]=2)[CH:11]=1)C1C=CC=CC=1.[OH-].[Na+].CCOCC>C1COCC1.O>[CH2:17]([O:16][C:14]1[CH:15]=[C:10]([CH:11]=[C:12]([O:25][CH2:26][C:27]2[CH:32]=[CH:31][CH:30]=[CH:29][CH:28]=2)[C:13]=1[Br:24])[C:9]([OH:33])=[O:8])[C:18]1[CH:19]=[CH:20][CH:21]=[CH:22][CH:23]=1To a stirred solution of 3,5-bis-benzyloxy-4-bromo-benzoic acid benzyl ester (200a) (225 g, 0.45 mol) in THF (400 mL) and H2O (500 mL) was added NaOH (89.4 g, 2.24 mol) in one portion. The mixture was refluxed for 4 hr. TLC (EtOAc/petroleum ether=1/4) showed that the reaction was complete. Et2O (100 mL) was added to the mixture and the organic layer was separated. The aqueous layer was acidified with conc. HCl, and the resulting solid was filtered and dried in vacuo to give the title compound (150 g, 85% yield) as a white solid. 1H NMR (400 MHz, CDCl3): δ 7.48 (dd, 4H), 7.39(t, 4H), 7.31 (m, 4H), 5.27(s, 4H).
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