N-bromobutanimide → tert-Butyl 4-(3-amino-6-bromopyrazin-2-yl)-2-fluorobenzoate

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of tert-butyl 4-(3-aminopyrazin-2-yl)-2-fluorobenzoate (37.7 g, 130 mmol) in acetonitrile (800 mL) at 0° C. was added N-bromosuccinimide (23.19 g, 130 mmol) in one portion. The reaction was stirred at 0° C. for 2 h, then quenched with saturated NaHCO3 solution (200 mL) and stirred at 0° C. for 30 min. The mixture was diluted with water (300 mL) and extracted with EtOAc (3×250 mL). The combined organics were washed with water (200 mL) and brine (2×200 mL), dried over magnesium sulfate, filtered and concentrated. The crude material was purified using flash chromatography on silica gel (0 to 40% EtOAc in heptane over 40 min), giving tert-butyl 4-(3-amino-6-bromopyrazin-2-yl)-2-fluorobenzoate (30.9 g, 64%) as a solid. LCMS (m/z): 368/370 (MH+), 1.03 min; 1H NMR (400 MHz, DMSO-d6) δ ppm 8.14 (s, 1H) 7.97-7.74 (m, 1H) 7.62-7.39 (m, 2H) 6.64 (s, 2H) 1.54 (s, 9H).

Provenance & Evidence