Synthesis of 4-Amino-2-chloro-6,7-dimethoxyquinazoline

4-Amino-2-chloro-6,7-dimethoxyquinazoline,a key intermediate of quinazoline drugs such as terazosin,was synthesized from vanillin by methylation,nitration,oxidation,esterification,reduction,cyclization, chlorination and animation.The effects of reaction temperature and mole ratio of the reactants were investigated in the nitration and oxidation.The overall yield of the target compound was about 37%after improvement of the process.