Phthalazine is a heterocyclic compound with the molecular formula C8H6N2 composed of a benzene ring fused with a pyridazine ring. Phthalazine and its derivatives do not exist in nature. Phthalazines are used as starting materials for organic synthesis. Studies have found that phthalazine has a variety of physiological activities, such as anti-cancer, antibacterial, anti-inflammatory and so on. The synthesis of phthalazine compounds with novel structures and better biological activities has become a research hotspot in recent years.
Tetrazoles are doubly unsaturated five-membered aromatic heterocycles consisting of one carbon atom and four nitrogen atoms. Tetrazole derivatives are a major class of heterocyclic compounds that are important for medicinal chemistry and drug design because of their not only isosteric properties with carboxylic acid and amide moieties, but also metabolic stability and other beneficial physicochemical properties.