Trifluoroacetic acid → 3-(4,5-Dibromo-3-chloro-thiophen-2-yl)-8-(1-ethyl-propyl)-2,6-dimethyl-imidazo[1,2-b]pyridazine

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Reaction Steps

To a solution of 3-(5-bromo-3-chloro-thiophen-2-yl)-8-(1-ethyl-propyl)-2,6-dimethyl-imidazo[1,2-b]pyridazine (5.92 g, 14.34 mmol) and trifluoroacetic acid (40 mL) and 98% H2SO4 (10 ml) is added NBS (3.83 g, 21.15 mmol). After 10 minutes the solution is poured into ice, and made basic with 5M NaOH. The slurry is extracted with EtOAc (3×100 mL), the combined organic layers washed with water (2×400 mL), brine (400 mL), dried over MgSO4, filtered and concentrated to furnish the title compound (6.61 g, 13.44 mmol, 94%). 1H NMR (CDCl3) δ 0.87 (t, J=7.5 Hz, 6H), 1.72-1.92 (m, 4H), 2.47 (s, 3H), 2.52 (s, 3H), 3.25-3.34 (m, 1H), 6.72 (s, 1H). LC/MS (m/z): calcd. for C17H18Br2ClN3S (M+H)+: 489.9; found: 490.0.

Provenance & Evidence