Into a 250-mL round bottom flask, was placed a solution of 5-(3,4-dimethylphenyl)pyrazin-2-amine (2 g, 10.04 mmol, 1.00 equiv) in dichloromethane (70 mL), pyridine (2.4 g, 30.34 mmol, 3.00 equiv), and a solution of 5-chloro-2-nitrobenzoyl chloride (2.21 g, 10.05 mmol, 1.00 equiv) in dichloromethane (20 mL). The resulting solution was stirred overnight at 25° C. in an oil bath, then diluted with 150 mL of dichloromethane and washed with 2×100 mL of diluted hydrochloric acid, 2×200 mL of brine and 2×100 mL of sodium carbonate (sat.), and then 2×200 mL of brine. The organic layer was dried over sodium sulfate and concentrated under vacuum. The crude product was triturated with 40 mL of ethyl acetate/n-hexane (1:1). This resulted in 3.66 g (95%) of 5-chloro-N-(5-(3,4-dimethylphenyl)pyrazin-2-yl)-2-nitrobenzamide as an off-white solid.
