N-bromobutanimide → 5-Bromo-2,6-Diamino-3-(2,3,5-trichlorophenyl)pyrazine

Participants

Reaction Conditions

Reaction Steps

N-Bromosuccinimide (0.194 g, 1.09×10−3 mole) was added over 20 min to a mixture of 2,6-Diamino-3-(2,3,5-trichlorophenyl)pyrazine (0.3 g, 1.04×10−3 mole) in dimethylsulfoxide (10 ml) and water (0.25 ml) below 15° C. The resulting reaction mixture was stirred at 15° C. for 1 hr, poured onto ice water (150 ml) and extracted with ethyl acetate (2×75 ml). The extract was then washed with 2 M sodium carbonate solution (50 ml) and water (100 ml), dried over anhydrous magnesium sulphate, filtered and the filtrate evaporated in vacuo. The residue was purified by ‘flash chromatography’ using 5-13% ethyl acetate in cyclohexane as the eluent. Yield 0.183 g (48%), M.p. 222-224° C.

Provenance & Evidence