Naphthalene is a hydrocarbon produced by the distillation of coal tar and is an aromatic white crystalline substance. Naphthalene is the most abundant component in coal tar. It is used as an insect repellant and insect fumigant. The compound is used in the manufacture of celluloid, dyes, hydrogenated naphthalenes, oil fumes, smokeless powders and synthetic resins.
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.