Widely used as a key intermediate in the synthesis of quinazoline-based pharmaceuticals, particularly in the development of antihypertensive and anticancer agents. Its chloro-substituted structure allows for selective functionalization, enabling the introduction of various side chains to enhance biological activity. Commonly employed in the preparation of tyrosine kinase inhibitors and benzodiazepine receptor modulators. Also utilized in research settings for structure-activity relationship (SAR) studies due to its rigid heterocyclic framework and hydrogen bonding capability.