反应详情

温度

2 °C

Charge a 2 L 3-neck round bottom flask with methanol (95 mL) and chill to 2° C. and slowly add acetyl chloride (7.62 mL, 0.107 mol) dropwise under nitrogen. In a separate 1 L 3-neck flask, dissolve 3′-chloro-4-(1,5-dimethyl-1H-pyrazol-4-ylmethyl)-3,4,5,6-tetrahydro-2H-[1,2′]bipyrazinyl (36.5 g, 0.107 mol) in toluene (365 mL). Add this solution to the methanolic HCl solution in one portion. Stir vigorously for 1 hr. and concentrate to one half volume and filter to give 3′-chloro-4-(1,5-dimethyl-1H-pyrazol-4-ylmethyl)-3,4,5,6-tetrahydro-2H-[1,2′]bipyrazinyl hydrochloride as a white solid (25.5 g, 87%). MS (ES): m/z=307.0 [M+H]+.

1. concentrationand concentrate to one half volume
2. filtrationfilter