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

Temperature

15 °C

N-Bromosuccinimide (0.194 g, 1.09×103 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.

1. customThe resulting reaction mixture
2. additionpoured onto ice water (150 ml)
3. extractionextracted with ethyl acetate (2×75 ml)
4. washThe extract was then washed with 2 M sodium carbonate solution (50 ml) and water (100 ml)
5. dry with materialdried over anhydrous magnesium sulphate
6. filtrationfiltered
7. customthe filtrate evaporated in vacuo
8. customThe residue was purified by ‘flash chromatography’

ORD record

ord-1858076994e746d0ae32addd9b7c62c3

Source dataset

uspto-grants-2003_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06503909B1