[OH:1][C:2]1[CH:3]=[CH:4][C:5]2[S:9][C:8]([S:10][CH3:11])=[N:7][C:6]=2[CH:12]=1.Br[CH2:14][CH2:15][Cl:16].C([O-])([O-])=O.[K+].[K+]>CN(C=O)C>[Cl:16][CH2:15][CH2:14][O:1][C:2]1[CH:3]=[CH:4][C:5]2[S:9][C:8]([S:10][CH3:11])=[N:7][C:6]=2[CH:12]=1To a solution of 5-hydroxy-2-methylthio-benzothiazole (2.1 g, 11 mmol) in anhydrous DMF (25 mL) was added bromo-2-chloroethane (4.4 mL, 53 mmol) and powdered K2CO3 (7.3 g, 53 mmol). The reaction slurry was heated at 70° C. for 13 h. The slurry was filtered under vacuum and the filtrate was concentrated under reduced pressure. The crude material was chromatographed (SiO2, 0-20% EtOAc/Hex) to afford the title compound (1.2 g, 46%). 1H-NMR (CDCl3): δ 7.62 (1H, d), 7.39 (1H, d), 6.97 (1H, dd), 4.29 (2H, t), 3.85 (2H, t), 2.79 (3H, s); MS(ESI): 259 (MH+).
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