To a round-bottomed flask equipped with a magnetic stirrer and a reflux condenser tube were added 3,4-diaminotoluene (1.0 mmol), 2,3-butanedione (1.0 mmol) and a catalyst (Cu(II)DiAmSar/SBA-15, 0.005 g). The reaction mixture was heated at 100 °C for an appropriate time and the reaction process was monitored by silica gel thin layer chromatography (TLC). After completion of the reaction, the reaction mixture was cooled and the crude product was purified by column chromatography or crystallization to give 2,3,6-trimethylquinoxaline. The spectral and physical data of the obtained product were in agreement with the reference sample and data reported in the literature.
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