Water → 2-Amino-3-bromo-5-methylpyrazine

To a suspension of 5-methylpyrazin-2-amine (1.09 g, 10 mmol) in chloroform (100 mL) was added pyridine (0.85 mL, 10.5 mmol). The mixture was stirred in a foil-wrapped flask fitted with an addition funnel, and a solution of bromine (0.54 mL, 10.5 mmol) in chloroform (10 mL) was added dropwise over 10 min. The mixture was allowed to react an additional 20 minutes after addition was complete and then poured into a separatory funnel containing 10 mL water. The phases were separated and the organics washed again with water, dried over sodium sulfate, filtered and concentrated in vacuo. The resulting red oil was purified by silica gel chromatography with 12-100% EtOAc/hexanes. The major UV active peak was collected to give 3-bromo-5-methylpyrazin-2-amine (1.06 g, 5.64 mmol, 56.4% yield) as a cream-colored solid. 1H NMR (500 MHz, DMSO-d6) δ ppm 7.85 (s, 1H) 6.42 (br. s., 2H) 2.25 (s, 3H). MS (LC/MS) R.T.=0.93; [M+H]+=189.9.

1. customfitted with an addition funnel
2. customto react an additional 20 minutes
3. additionafter addition
4. additionpoured into a separatory funnel
5. customThe phases were separated
6. washthe organics washed again with water
7. dry with materialdried over sodium sulfate
8. filtrationfiltered
9. concentrationconcentrated in vacuo
10. customThe resulting red oil was purified by silica gel chromatography with 12-100% EtOAc/hexanes
11. customThe major UV active peak was collected

ORD record

ord-10c123996df84035831a42c218e977c3

Source dataset

uspto-grants-2012_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08309577B2