C([O:3][C:4]([C:6]1[O:7][C:8]2[CH:15]=[CH:14][CH:13]=[C:12]([O:16][CH2:17][CH:18]([OH:24])[CH2:19][NH:20][CH:21]([CH3:23])[CH3:22])[C:9]=2[C:10]=1[CH3:11])=[O:5])C.[OH-].[Na+].Cl>CO>[OH:24][CH:18]([CH2:19][NH:20][CH:21]([CH3:23])[CH3:22])[CH2:17][O:16][C:12]1[C:9]2[C:10]([CH3:11])=[C:6]([C:4]([OH:5])=[O:3])[O:7][C:8]=2[CH:15]=[CH:14][CH:13]=1A solution of 4-(2-hydroxy-3-isopropylamino-propoxy)-3-methyl-benzofuran-2-carboxylic acid ethyl ester (100 mg) in methanol (5 ml) was treated with 5 N NaOH solution (1 ml) at room temperature, and the resulting mixture was stirred overnight at the same temperature. The solution was acidified with 1N HCl solution (6 ml) and concentrated in vacuo. The residue was dissolved in H2O and passed through Sep-Pak Cartridge (C18) which was developed with H2O-MeOH. The fractions containing the target compound were collected and concentrated in vacuo to give 4-(2-hydroxy-3-isopropylamino-propoxy)-3-methyl-benzofuran-2-carboxylic acid (79 mg) as a white powder. FAB-MS: m/z 308 (MH+); 1H-NMR (DMSO-d6): δ 1.05 (6H, d, J=6 Hz), 2.65 (3H, s), 2.73 (1H, dd, J1=12 Hz, J2=7 Hz), 2.86 (2H, m), 3.99 (1H, m), 4.16 (2H, d, J=5 Hz), 6.68 (1H, d, J=8 Hz), 7.01 (1H, d, J=8 Hz), 7.17 (1H, t, J=8 Hz).
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