Chloroacetaldehyde → Imidazo(1,2-a)pyrazine

Temperature

100 °C

Pyrazin-2-amine 4a (5 g, 52 mmol) was dissolved in a 40% 2-chloroacetaldehyde solution (15 mL, 78 mmol), followed by addition of sodium bicarbonate (6.60 g, 78 mmol). After stirring for 48 hours at 100° C., the reaction mixture was cooled to room temperature, added with 100 mL of a saturated potassium carbonate solution, and extracted with dichloromethane (100 mL×3). The organic phase was combined, dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated under reduced pressure to obtain imidazo[1,2-a]pyrazine 4b (3 g, yield 50.0%) as a brown solid.

1. temperaturethe reaction mixture was cooled to room temperature
2. extractionextracted with dichloromethane (100 mL×3)
3. dry with materialdried over anhydrous sodium sulfate
4. filtrationfiltered
5. concentrationThe filtrate was concentrated under reduced pressure

ORD record

ord-18e409b58c634ae8986b858380f617b3

Source dataset

uspto-grants-2016_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09273052B2