[Br:1]Br.[Br:3][C:4]1[N:9]=[CH:8][C:7]([C:10](=[O:12])[CH3:11])=[CH:6][CH:5]=1.Br>C(Cl)Cl>[Br:1][CH2:11][C:10]([C:7]1[CH:8]=[N:9][C:4]([Br:3])=[CH:5][CH:6]=1)=[O:12]A solution of bromine (4 g, 25 mmol) in DCM (10 mL) was added drop wise over 5 min to a cooled (0° C.) solution of 1-(6-bromo-pyridin-3-yl)-ethanone (5 g, 25 mmol) and HBr (48%, 0.2 mL). The cooling bath was removed 40 min later and stirring was continued at RT for 66 h. The solid that formed was filtered, washed with DCM and dried at room temperature to give the impure title intermediate (8.1 g) as a yellow solid. 1H NMR (CD3OD, 400 MHz) δ (ppm): 8.96 (m, 1H), 8.28-8.25 (m, 1H), 7.82-7.79 (m, 1H), 4.7 (s, 2H).
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