Sodium Sulfite → 3-Bromo-7-{[2-chloro-3-(trifluoromethyl)phenyl]carbonyl}-2-(trifluoromethyl)-5,6,7,8-tetrahydroimidazo[1,2-a]pyrazine

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Reaction Steps

7-{[2-Chloro-3-(trifluoromethyl)phenyl]carbonyl}-2-(trifluoromethyl)-5,6,7,8-tetrahydroimidazo[1,2-a]pyrazine (0.181 g, 0.455 mmol, Example 2) was dissolved in N,N-dimethylformamide (DMF) (2 mL) and treated with N-bromosuccinimide (NBS, 0.097 g, 0.546 mmol). The solution was stirred at room temperature for 16 hr. The mixture was poured onto water (100 ml) containing 1% sodium sulfite (w/w) and extracted into ethyl acetate (3×50 ml). The combined extracts were washed with brine (50 ml), dried over anhydrous sodium sulfate and concentrated to afford crude product (0.323 g). The crude product was purified by mass-directed automated preparative HPLC to afford 3-bromo-7-{[2-chloro-3-(trifluoromethyl)phenyl]carbonyl}-2-(trifluoromethyl)-5,6,7,8-tetrahydroimidazo[1,2-a]pyrazine (0.135 g, 0.283 mmol, 62.2% yield).

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