[CH3:1][C:2]1[N:7]2[N:8]=[C:9](N)[N:10]=[C:6]2[C:5]([CH3:12])=[N:4][CH:3]=1.N([O-])=O.[Na+].C(Br)(Br)[Br:18].ClC(Cl)C(O)=O>[Br-].C([N+](CC)(CC)CC)C1C=CC=CC=1.[Al].O>[Br:18][C:9]1[N:10]=[C:6]2[C:5]([CH3:12])=[N:4][CH:3]=[C:2]([CH3:1])[N:7]2[N:8]=1
A mixture of 5,8-dimethyl-[1,2,4]triazolo[1,5-a]pyrazin-2-ylamine (2.4 g, 14.71 mmol), sodium nitrite (10.15 g, 147.08 mmol) and benzyltriethylammonium bromide (8 g, 29.42 mmol) in bromoform (76.2 ml, 872.17 mmol) was stirred at 25° C. for 30 minutes. To this mixture was then added dichloroacetic acid (2.43 ml, 29.42 mmol) and the reaction mixture was stirred at 25° C. for further 20 hours. (The reaction flask was wrapped in aluminum foil to protect the mixture from light). Water (100 ml) was added to the reaction mixture, which was then stirred for 30 minutes at 25° C., and finally extracted 4 times with dichloromethane. The combined organic layers were washed twice with water and brine, dried over anhydrous sodium sulfate, filtered and evaporated. The crude material thus obtained was purified by silica gel column chromatography using hexane ethyl acetate 20% as eluent affording 2-bromo-5,8-dimethyl-[1,2,4]triazolo[1,5-a]pyrazine (4.8 g, 74.72%) as an off white solid. MS: m/z=227 (M+H+)
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