1 L three-neck round-bottom flask was charged with 2-chloropyrazine (60.0 g, 0.521 mol, 2.00 eq.), ethyl 2-[(diphenylmethylidene)amino]acetate (70.0 g, 0.262 mol, 1.00 eq.), N-methylpyrrolidone (600 mL), tetrabutylammonium bromide (84.4 g, 0.262 mol, 1.00 eq.) and potassium carbonate (109 g, 0.790 mol, 3.00 eq.). The mixture was stirred overnight at 100 °C under N2 atmosphere. The solid was filtered off, and the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography with ethyl acetate:petroleum ether (EA:PE) (1:10) to afford ethyl 2- [(diphenylmethylidene)amino]-2-(pyrazin-2-yl)acetate (54.0 g, 60% yield) as a yellow oil.