Ammonia → 5-Quinazolinol, 2-methyl- (9CI)

To a stirred solution of 5-methoxy-2-methylquinazoline (0.22 g, 1.26 mmol) in dichloromethane (20 mL) at 0° C. under argon was added a solution of boron tribromide in dichloromethane (1M, 3.8 mL), dropwise over 0.01 h. The resulting mixture was stirred at 20° C. for 48 h then poured into a mixture of ice (50 g) and 0.880 aqueous ammonia (50 mL) and stirred for 0.5 h. Organic phase was separated and aqueous phase washed with dichloromethane (3×30 mL). The aqueous phase was acidified (pH 6) with citric acid and the resulting mixture extracted with ethyl acetate (3×50 mL). The combined ethyl acetate extracts were dried (Na2SO4) and evaporated in vacuo to give the title compound (0.030 g, 15%) as an oil which was used without further purification.