Nicotelline
Nicotelline is an alkaloid first identified in 1914 as a chemical constituent of tobacco plants (Nicotiana). The chemical structure of nicotelline wasn't elucidated until 1956, when it was determined that nicotelline is a terpyridine consisting of three linked pyridine rings. This structure was confirmed by laboratory synthesis. Nicotelline has the molecular formula . It is a crystalline solid with a melting point of 147-148 °C. It is soluble in hot water, chloroform, ethanol, and benzene. Nicotelline has long been known to be a constituent of tobacco smoke. As such, it has recently been proposed as a biomarker or environmental tracer for tobacco smoke. References

Alkaloids
Pyridines