Chloroacetone → 8-Chloro-2-methylimidazo[1,2-a]pyrazine

Temperature

0 °C

A solution of 2-amino-3-chloropyrazine (10 g, 77.5 mmol), chloroacetone (30 mL, 387 mmol) in MeOH (25 mL) is refluxed overnight at 88° C. It is then stirred for 1 h at 0° C. and any solid that forms, is filtered off and washed twice with MeOH (5 mL). The mother liq. are evaporated, diluted with EtOAc, and washed with HCl 2N, water and brine. The water and HCl mother liq. are evaporated to give a yellow solid that is neutralized with a saturated solution of K2CO3 in water, extracted with DCM, dried with MgSO4 anh. filtered and concentrated. The crude material is purified by column chromatography using a gradient of (DCM/MeOH: 1/0 to 99/1) to give 8-Chloro-2-methyl-imidazo[1,2-a]pyrazine as an orange solid (1.02 g, 7.7%).

1. filtrationany solid that forms, is filtered off
2. washwashed twice with MeOH (5 mL)
3. customThe mother liq. are evaporated
4. additiondiluted with EtOAc
5. washwashed with HCl 2N, water and brine
6. customThe water and HCl mother liq. are evaporated
7. customto give a yellow solid
8. extractionextracted with DCM
9. dry with materialdried with MgSO4 anh. filtered
10. concentrationconcentrated
11. customThe crude material is purified by column chromatography

ORD record

ord-11bc6c510268416392ca4501d243b67c

Source dataset

uspto-grants-2013_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08362018B2