[CH3:1][C:2]([C:4]1[CH:9]=[CH:8][C:7]([O:10][CH3:11])=[C:6]([O:12][CH3:13])[CH:5]=1)=[O:3].[CH2:14]=O.Cl.[CH3:17][NH:18][CH3:19]>C(O)C>[CH3:13][O:12][C:6]1[CH:5]=[C:4]([C:2](=[O:3])[CH2:1][CH2:17][N:18]([CH3:14])[CH3:19])[CH:9]=[CH:8][C:7]=1[O:10][CH3:11]To a stirred solution of 3,4-Dimethoxy acetophenone (3 g, 0.0166 moles, 1 equiv.) in ethanol was added paraformaldehyde (0.5 g, 0.0166 moles, 1 equiv.), dimethylamine hydrochloride (4.2 g, 0.0499 moles, 3 equiv.) and the reaction mixture was refluxed at 80° C. for 12 h. Consumption of starting materials was confirmed by LC-MS analysis and TLC. Ethanol was evaporated under reduced pressure; the crude solid residue was stirred with acetone at 0° C. for 1 h, filtered, washed with acetone, dried under vacuum. After that the solid was suspended in water, basified with 10% sodium bicarbonate solution (pH˜8), extracted by dichloromethane (2×200 ml), washed with water followed by satd. Brine solution. The organic layer was dried over sodium sulfate and concentrated to get 2.9 g (73% yield) title compound as green oily liquid. It was taken forward for the next step without any further purification.
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