Triethylamine → 2-bromo-N-(pyrazin-2-yl)acetamide

A stirred solution of amino pyrazole (10 g, 105 mmol) in acetone (100 ml) is treated with triethylamine (16.1 ml, 115 mmol) and then cooled to 0-5° C. using an ice bath. To the cooled solution is added drop-wise bromoacetyl chloride (8.76 g, 105 mmol) in acetone (10 ml). The cooled reaction mixture is stirred for 3 hours and then filtered. The solvent is removed in vacuo and purification by chromatography on silica (eluting with ethyl acetate-iso-hexane, 2:1 increasing to 100% ethyl acetate) affords the titled compound.