The acylation of piperazine (I) with 1,4-benzodioxan-2-ylcarbonyl chloride (II) by means of sodium acetate in water-acetone gives N-(1,4-benzodioxan-2-carbonyl)piperazine (III), which is then condensed with 4-amino-2-chloro-6,7-dimethoxyquinazoline (IV) in refluxing butanol.