[CH3:1][O:2][C:3]1[CH:4]=[C:5]([NH:11][C:12](=[O:14])[CH3:13])[CH:6]=[C:7]([O:9][CH3:10])[CH:8]=1.Cl.[Cl:16]([O-])(=O)=O.[Na+].C([O-])([O-])=O.[K+].[K+]>C(O)(=O)C.O>[Cl:16][C:6]1[C:7]([O:9][CH3:10])=[CH:8][C:3]([O:2][CH3:1])=[CH:4][C:5]=1[NH:11][C:12](=[O:14])[CH3:13]To a stirred solution of N-(3,5-dimethoxy-phenyl)-acetamide (5 g, 25.64 mmol) in acetic acid (17 mL) was added 32% aqueous hydrochloric acid solution (14 mL), followed by a solution of sodium chlorate (1.16 g, 11 mmol) in water (1.5 mL) at 0° C. The resulting reaction mixture was stirred for 30 min. at 0° C. Thereafter reaction mixture was poured into ice water and made it basic with K2CO3 powder. The precipitate was filtered off and washed with water. The residue was purified by silica gel column chromatography (Hexane/EtOAc, 88:12) to afford the title compound (1.8 g, 31% of yield) as a white solid. 1HNMR (DMSO-d6, 300 MHz): δ 9.36 (s, 1H), 7.03 (d, 1H), 6.53 (d, 1H), 3.84 (s, 3H), 3.74 (s, 3H), 2.08 (s, 3H); MS (ESI): 230.2 [M+H]+.
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