Tetrahydrofuran → 6-Bromo-2-methoxypyrido[3,2-d]pyrimidine

A 3-necked roundbottom flask purged and maintained with an inert atmosphere of nitrogen was charged with 2,6-dibromopyrido[3,2-d]pyrimidine (10.7 g, 37.04 mmol). To this was added tetrahydrofuran (500 ml) and methanol (150 ml). A solution of sodium (89 mg, 3.87 mmol, 0.10 equiv) in methnaol (60 ml) was then added dropwise with stirring, while warming to a temperature of 40° C. The resulting solution was allowed to react, with stirring, for 1.5 hours while the temperature was maintained at 40° C. The reaction progress was monitored by TLC. The reaction mixture was then quenched by adding 1.5 L of water. The mixture was concentrated under reduced pressure. The resulting slurry was filtered and the solids collected. The solids were then dissolved in 2 L of ethyl acetate. The resulting mixture was washed once with 500 ml of brine. The organic layer was dried over magnesium sulfate, filtered, and concentrated under reduced pressure. The resulting residue was purified recrystallization from 2:1 tetrahydrofuran:methanol to afford the title compound.