[CH2:1]([O:8][C:9]1[CH:10]=[CH:11][C:12]([O:18][CH3:19])=[C:13]([CH:17]=1)[C:14](O)=[O:15])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.C(Cl)(=O)C(Cl)=O.[NH4+:26].[OH-].Cl>C(Cl)Cl.C1COCC1>[CH2:1]([O:8][C:9]1[CH:10]=[CH:11][C:12]([O:18][CH3:19])=[C:13]([CH:17]=1)[C:14]([NH2:26])=[O:15])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1
To a stirred solution of 5-(benzyloxy)-2-methoxybenzoic acid (8, 1.16 g. 4.5 mmol) in CH2Cl2 (25 mL) at room temperature was added oxalyl chloride (1.5 mL, 17.9 mmol). The reaction mixture was stirred at room temperature for 2 h. It was concentrated to dryness to provide the crude acid chloride as a brown-yellow waxy solid. The crude acid chloride was dissolved in THF (10 mL) and was added dropwise to a stirred mixture of concentrated NH4OH (20 mL) and THF (10 mL) at 0° C. The reaction mixture was warmed to room temperature and stirred for 1 h and was adjusted to pH 8 with 2 N HCl. The precipitate was collected, washed with water, and dried in vacuo to afford the title compound (0.73 g, 63%) as a white solid: 1H NMR (500 MHz, CDCl3) δ 7.88 (d, J=3.3 Hz, 1H), 7.82 (br s, 1H), 7.47-7.43 (m, 2H), 7.40-7.37 (m, 2H), 7.33-7.30 (m, 1H), 7.10 (dd, J=9.0, 3.3 Hz, 1H), 6.94 (d, J=9.0 Hz, 1H), 5.75 (br s, 1H), 5.08 (s, 2H), 3.94 (s, 3H); ESI MS m/z 258 [M+H]+.
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