Although nicotine and caffeine may at first glance seem unrelated they are in fact very similar. Structurally they both contain a pyridine ring and a pyrrolidine ring joined by a single bond. Both caffeine and nicotine are stimulants, meaning they can both induce heightened alertness and mental process temporarily. Increased heart rate, blood pressure, and production of adrenaline are also side effects. Both amines are found in plants and have been used throughout history as “stay-awake” drugs.
A pyridine ring is a ring of five carbon atoms and a nitrogen atom that is structurally similar to a benzene ring. A pyrrolidine ring is a ring composed of four carbon atoms and a nitrogen atom with a hydrogen atom attached.
These two legal stimulants are widely used today because of their long history of cultural acceptance. Today many people refer to caffeine as the only drug that kids can legally abuse. It is very interesting to think that the only thing that separates caffeine from nicotine is two carbon atoms and two hydrogen atoms.
Baird, Colin. Chemistry in Your Life. Second Edition. “Nitrogen atoms are found in nicotine and caffeine”. Page 297-300. W.H. Freeman and Company. New York. 2006.