Pyridine → N-(5-bromopyrazin-2-yl)-2,2-dimethylpropanamide

Participants

Reaction Conditions

Reaction Steps

A solution of 2-amino-5-bromopyrazine (10.00 g, 57.47 mmol) and pyridine (5.6 mL, 68.96 mmol) in methylene chloride (144 mL) was cooled to 0° C. and then was treated slowly with trimethylacetyl chloride (8.6 mL, 68.96 mmol). The resulting reaction mixture was stirred at 0° C. for 30 min and then was allowed to warm to 25° C. where it was stirred for 18 h. At this time, the reaction mixture still contained the starting material 2-amino-5-bromopyrazine. The reaction mixture was treated with an additional amount of trimethylacetyl chloride (4.3 mL, 34.48 mmol) and then stirred at 25° C. for 4 h. The reaction mixture was then concentrated in vacuo to remove methylene chloride. The resulting residue was diluted with ethyl acetate (700 mL). The organic layer was washed with a 1N aqueous hydrochloric acid solution (2×200 mL) and a saturated aqueous sodium chloride solution (1×200 mL), dried over sodium sulfate, filtered, and concentrated in vacuo. Biotage chromatography (FLASH 65M, Silica, 1/9 ethyl acetate/hexanes) afforded N-(5-bromo-pyrazin-2-yl)-2,2-dimethyl-propionamide (12.19 g, 82%) as a white solid: mp 122–124° C.; (ES)+-HRMS m/e calcd for C9H12BrN3O (M+H)+ 258.0237, found 258.0240.

Provenance & Evidence