To a solution of N-cyclopropyl-3-[6-(2,3-dihydroxy-2-methylpropoxy)-4-oxoquinazolin-3(4H)-yl]-4-methylbenzamide (0.2 g) in pyridine (10 ml) was added p-toluenesulfonylchloride (0.18 g) followed by 4-dimethylaminopyridine (cat.) and the mixture heated at 60° C. for 18 hours. The reaction mixture was concentrated under reduced pressure and redissolved in ethyl acetate. The organics were washed with 1N citric acid, brine, dried (magnesium sulfate) and concentrated to give the crude 3-[(3-{5-[(cyclopropylamino)carbonyl]-2-methylphenyl}-4-oxo-3,4-dihydroquinazolin-6-yl)oxy]-2-hydroxy-2-methylpropyl 4-methylbenzenesulfonate (0.21 g) which was used without further purification.
