Aminopyrazine → 2-(Trifluoromethyl)imidazo[1,2-a]pyrazine

2-Aminopyrazine (12.5 g, 0.13 mol) and 3-bromo-1,1,1-trifluoro-propan-2-one (27.6 g, 0.14 mol) in ethanol (150 ml) was heated at reflux for 24 hours. A further portion of 3-bromo-1,1,1-trifluoro-propan-2-one (2.51 g, 14 mmol) was added and the mixture was heated at reflux for 18 hours. The solvent was evaporated under reduced pressure and the residue was dissolved in water (30 ml). Solid sodium hydrogen carbonate was added to bring the pH to 8 and the solution was extracted with dichloromethane (×3). The combined organic layers were washed with water (20 ml) dried over magnesium sulphate and evaporated under reduced pressure. The residue was purified by medium pressure chromatography on silica gel using methanol in dichloromethane as eluant (gradient from 2:98 to 4:96). The material isolated was further purified by chromatography on silica gel using methanol in dichloromethane as eluant (2:98). The material isolated was recrystallised from ethyl acetate/hexane to give the title compound as an orange brown solid (3 g).

1. temperatureat reflux for 24 hours
2. temperaturethe mixture was heated
3. temperatureat reflux for 18 hours
4. customThe solvent was evaporated under reduced pressure
5. dissolutionthe residue was dissolved in water (30 ml)
6. additionSolid sodium hydrogen carbonate was added
7. extractionthe solution was extracted with dichloromethane (×3)
8. washThe combined organic layers were washed with water (20 ml)
9. dry with materialdried over magnesium sulphate
10. customevaporated under reduced pressure
11. customThe residue was purified by medium pressure chromatography on silica gel
12. customThe material isolated
13. customwas further purified by chromatography on silica gel
14. customThe material isolated
15. customwas recrystallised from ethyl acetate/hexane

ORD-Eintrag

ord-a165851dff2747e197bf007719f1c22c

Quelldatensatz

uspto-grants-2007_01

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07157468B2