[C:1]1([C:7]2[N:8]=[C:9]3[CH2:14][CH2:13][CH2:12][CH2:11][N:10]3[CH:15]=2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.[Br:16]Br.C([O-])(O)=O.[Na+]>C(Cl)Cl>[Br:16][C:15]1[N:10]2[CH2:11][CH2:12][CH2:13][CH2:14][C:9]2=[N:8][C:7]=1[C:1]1[CH:2]=[CH:3][CH:4]=[CH:5][CH:6]=1To a solution of 2-phenyl-5,6,7,8-tetrahydro-imidazo[1,2-a]pyridine (1.7 g, 8.9 mmol) in dry CH2Cl2 (55 mL) slowly add bromine (0.5 mL, 9.8 mmol) and stir at room temperature for 3 hours. Then, add a saturated aqueous solution of NaHCO3 (100 mL) and extract with CH2Cl2 (3×100 mL). Wash the combined organic layers with NaHSO3 (40%, 30 mL) followed by saturated aqueous sodium chloride (50 mL), dry (MgSO4), and concentrate in vacuo. Purify the residue by flash chromatography (SiO2, eluent:CH2Cl2 to CH2Cl2/MeOH 20:1) to obtain a brown solid, 2.0 g, 82% yield. MS((ES+): m/z=277.0, (M+H)+
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