27383-91-1

10531-78-9

124-38-9

74-88-4

27383-91-1

Catalyst (9.9 mg, 0.025 mmol, 5 mol%), potassium tert-butoxide (0.0672 g, 0.6 mmol) and DMF (3.0 mL) were added to the reaction flask under argon protection. Subsequently, 5-methylbenzazole (66.58 mg, 0.5 mmol) was added and the reaction mixture was stirred at 80 °C for 18 h at atmospheric pressure. After completion of the reaction, the system was cooled to 65 °C, iodomethane (93 μL, 1.5 mmol) was added and stirring was continued for 1 h at the same temperature. At the end of the reaction, the reaction was quenched with ethyl acetate and purified by column chromatography (eluent: ethyl acetate/petroleum ether, 1:10, v/v) to afford the target product methyl 5-methylbenzo[D]oxazole-2-carboxylate in 88% yield.