pyrrol

Pyrrol is a five-membered heterocyclic organic compound with the chemical formula C4H5N. It features a fully unsaturated ring containing one nitrogen atom and four carbon atoms. Pyrrol is aromatic, meaning it possesses a planar ring structure with a delocalized pi electron system. This aromaticity contributes to its chemical stability.

The pyrrol ring is a fundamental building block in many biologically important molecules. For instance, it is a key component of porphyrins, which are essential for the function of heme in hemoglobin and chlorophyll in plants. The nitrogen atom in pyrrol can act as a weak base.

Pyrrol itself is a colorless liquid that turns brown when exposed to air. It is soluble in water and most organic solvents. It can be synthesized through various methods, including the Paal-Knorr pyrrole synthesis, which involves the reaction of a 1,4-dicarbonyl compound with ammonia or a primary amine. Derivatives of pyrrol are widespread in nature and in synthetic chemistry, finding applications in pharmaceuticals, dyes, and polymers.