Compared to quinolines, isoquinolines are also prominent structural motifs present in many biologically significant natural and synthetic compounds. Some well-known isoquinoline alkaloids include the anticancer and anticonvulsant berberine, the vasodilator and antispasmodic drugs papaverine and emetine. In addition to naturally occurring isoquinolines, synthetic analogs have also shown significant biological activity.
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.