A mixture of ethyl 2-((diphenylmethylene)amino)acetate (6.0 g, 22.47 mmol), 2-bromopyrazine (7.1 g, 44.90 mmol), potassium carbonate (9.30 g, 67.40 mmol) and tetrabutyl ammonium iodide (8.10 g, 22.40 mmol) in N-methyl-2-pyrrolidone (25 mL) was heated in a sealed tube at 110° C. for 16 hours. The mixture was poured into water (100 mL) and extracted with ethyl acetate (3×50 mL). The organic layers were washed with brine (25 mL) and dried over sodium sulfate. Removal of solvent under vacuum afforded crude product which was purified in Combi-Flash instrument using a gradient of methanol in chloroform. Yield: 4.90 g (63%). 1H NMR (300 MHz, DMSO-d6) δ: 1.16 (t, 3H), 4.07 (q, 2H), 5.26 (s, 1H), 7.18 (dd, 2H), 7.38-7.61 (m, 8H), 8.56 (d, 1H), 8.57 (d, 1H), 8.60 (s, 1H). MS (ES) MH+: 346.3 for C21H19N3O2.
