2-Amino-3,5-dibromopyrazine → 2-Amino-5-bromo-3-methoxypyrazine

A 30% w/w solution of NaOMe in MeOH (8.4 mL, 44.8 mmol) was added to a stirring suspension of 3,5-dibromo-2-aminopyrazine (10 g, 39.5 mmol) in dry MeOH (40 mL). The reaction mixture was heated to reflux and maintained for 3 h. The reaction was allowed to cool to rt and concentrate to 1/3 volume. The reaction was then partitioned between DCM and saturated aqueous NaHCO3 solution. The layers were separated and the organic phase was washed with saturated aqueous NaHCO3 solution (3×). The combined aqueous portions were back extracted with DCM (3×). The combined organic portions were washed with brine, dried (Na2SO4), and concentrated to provide 8.1 g of 5-bromo-3-methoxypyrazin-2-amine: 1H NMR (300 MHz, CDCl3): 7.64 (s, 1H), 4.79 (br s, 2H), 4.01 (s, 3H).

1. temperatureThe reaction mixture was heated
2. temperatureto reflux
3. temperaturemaintained for 3 h
4. concentrationconcentrate to 1/3 volume
5. customThe reaction was then partitioned between DCM and saturated aqueous NaHCO3 solution
6. customThe layers were separated
7. washthe organic phase was washed with saturated aqueous NaHCO3 solution (3×)
8. extractionThe combined aqueous portions were back extracted with DCM (3×)
9. washThe combined organic portions were washed with brine
10. dry with materialdried (Na2SO4)
11. concentrationconcentrated

ORD record

ord-5faa875b7a154b739555ca30d32ca7df

Source dataset

uspto-grants-2014_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08865732B2