General procedure for the synthesis of 4-chloro-7-methoxy-6-ol from 6-acetoxy-4-chloro-7-methoxyquinazoline: 4-chloro-7-methoxyquinazolin-6-yl acetate (prepared according to the method described in Example 25-5 of WO01/66099, 10.1 g, 40 mmol) was suspended in 6 N methanol-ammonia solution (200 mL) and stirred at room temperature for 90 minutes at room temperature. Upon completion of the reaction, the solvent was removed by evaporation under vacuum. Water was added to the residue and the resulting suspension was filtered. The collected solids were washed sequentially with water and ether and subsequently dried at high temperature. Finally, vacuum drying in the presence of phosphorus pentoxide gave 4-chloro-7-methoxyquinazolin-6-ol (7.9 g, 94% yield). The NMR hydrogen spectrum (DMSO-d6) data were as follows: δ 4.02 (s, 3H), 7.40 (s, 1H), 7.43 (s, 1H), 8.81 (s, 1H).
