Isoquinoline

Isoquinoline is a heterocyclic aromatic organic compound. It is a structural isomer of quinoline. Isoquinoline is also obtained by ring fusion of pyridine and with a benzene ring. It was first isolated by Hoogewerff and Drop from the quinoline fraction of coal tar in 1885. Several derivatives of Isoquinoline also occur in coal tar. Isoquinoline does not occur free in nature but founds frequently in several alkaloids. It is called 2-azanaphthalene or benzo[b]pyridine. The numbering of the atoms in Isoquinoline is similar as followed in quinoline; however, the nitrogen atom is assigned position-2. Isoquinoline has close similarities in the structure with quinoline; therefore both have a close relationship in their physical and chemical properties.