). The reaction mixture was stirred at 25 °C for 3 hours. Upon completion of the reaction, the mixture was acidified to pH < 7 with dilute hydrochloric acid and a white solid was precipitated. The solid product was collected by filtration, washed with deionized water and subsequently dried under vacuum. Finally, the crude product was purified by silica gel column chromatography (eluent: petroleum ether/ethyl acetate=1:1, v/v) to afford the target compound 2-methyl-5-benzoxazolecarboxylic acid (0.30 g, 65% yield) as a white solid.
