GENERAL METHODS: To a solution of 6,7-dimethoxyquinazoline (200.0 mg, 1.05 mmol) in anhydrous ethanol (20 mL) was sequentially added 40% peracetic acid (1.0 mL, 5.26 mmol) and concentrated sulfuric acid (0.01 mL, 1.8 mmol). The reaction mixture was stirred in an oil bath at 60 °C for 4-12 h (the progress of the reaction was monitored by TLC). Upon completion of the reaction, the system was cooled to room temperature and residual peroxides were quenched by the addition of excess sodium bisulfite (541.8 mg, 5.26 mmol). After continued stirring for 20 min, the insoluble material was removed by filtration and the filtrate was concentrated under reduced pressure to give the crude product. The crude product was washed with a solvent mixture of ethanol and petroleum ether (1:1, v/v) to afford 6,7-dimethoxyethoxyquinazolin-4-one (179.7 mg, 83% yield) as a light yellow solid with a melting point of >300°C. The crude product was washed with a solvent mixture of ethanol and petroleum ether (1:1, v/v) to afford 6,7-dimethoxyethoxyquinazolin-4-one as a light yellow solid.
