To a solution of 5-(5-(quinazolin-4-yloxy)pentyloxy)-2-(hydroxymethyl)-4H-pyran-4-one 15 (0.53 g, 1.49 mmol) in CH2Cl2 (20 mL) was added at 0° C. triethylamine (252 μL, 1.78 mmol), methanesulfonyl chloride (138 μL, 1.78 mmol). The solution was stirred at RT for 1 h. Dichloromethane (50 mL) was added and the solution was washed with water (2×100 mL), dried over MgSO4, filtered and evaporated. (5-(5-(Quinazolin-4-yloxy)pentyloxy)-4-oxo-4H-pyran-2-yl)methyl methanesulfonate 20 was obtained (0.64 g, 99% yield) as a pale yellow oil.
