[Cl:1][C:2]1[CH:3]=[C:4]([CH:8]=[CH:9][C:10]=1[Cl:11])[CH:5]=[N:6][OH:7].[Cl:12]N1C(=O)CCC1=O>CN(C)C=O.O>[Cl:1][C:2]1[CH:3]=[C:4]([C:5]([Cl:12])=[N:6][OH:7])[CH:8]=[CH:9][C:10]=1[Cl:11]The title compound of Step A (3.7 g) was dissolved in 100 mL of dimethylformamide and 2.6 g of N-chlorosuccinimide was added. The reaction mixture was stirred at about 30° C. for 2 h and then at room temperature overnight. The mixture was diluted with 200 mL of water and extracted with three 100 mL portions of diethyl ether. The combined organic extracts were dried (MgSO4), filtered, and concentrated to give 5.8 g of the title compound of Step B as an oil. 1H NMR (CDCl3): δ 10.41 (s,1H), 7.95 (d,1H,J=2 Hz), 7.69 (dd,1H,J=2, 8 Hz), 7.46 (d,1H,J=8 Hz). The crude oil also contained DMF. The crude material was triturated in hexane and collected by filtration to yield 5.2 g of white solid, still containing DMF, which was used in the next step without additional purification or characterization.
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