Bromine → 3-Bromoimidazo(1,2-a)pyrazine

Temperature

-10 °C

Imidazo[1,2-a]pyrazine (1.191 g, 10 mmol, Intermediate 1) and sodium acetate (0.984 g, 12.00 mmol) were suspended in methanol (10 ml) saturated with potassium bromide (excess) and cooled to −10° C. Bromine (0.515 mL, 10.00 mmol) was added dropwise and the mixture stirred at −10° C. for 10 min. The solution was quenched by the addition of 1N sodium sulfite solution (10 ml) and concentrated in vacuo. The residue was partitioned between ethyl acetate (100 ml) and 50% saturated sodium bicarbonate solution (100 ml). The aqueous phase was extracted with ethyl acetate (2×100 ml), combined, washed with brine (50 ml), dried over anhydrous sodium sulfate and concentrated to give crude 3-bromoimidazo[1,2-a]pyrazine (1.66 g, 8.38 mmol, 84% yield) that was used in subsequent steps without further purification 3-bromoimidazo[1,2-a]pyrazine (1.66 g, 8.38 mmol, 84% yield).

1. customThe solution was quenched by the addition of 1N sodium sulfite solution (10 ml)
2. concentrationconcentrated in vacuo
3. customThe residue was partitioned between ethyl acetate (100 ml) and 50% saturated sodium bicarbonate solution (100 ml)
4. extractionThe aqueous phase was extracted with ethyl acetate (2×100 ml)
5. washwashed with brine (50 ml)
6. dry with materialdried over anhydrous sodium sulfate
7. concentrationconcentrated

ORD record

ord-a38ee1bb9fa74b64ab2c2707adc97017

Source dataset

uspto-grants-2013_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08513248B2