Pyrrole
In organic chemistry, a pyrrole is a five membered aromatic ring, 4 elements of which are carbon atoms, one element of which is a nitrogen atom. The molecular formula for a pyrrole is C4NH5.
Pyrroles are components of larger aromatic rings, including the porphyrins of heme, the chlorins and bacteriochlorins of chlorophyll, and the corrin ring of vitamin B12.
Pyrrole has very low basicity compared to many other nitrogen containing compounds. This is because nitrogens lone pair becomes delocalized in the aromatic ring and thus not very accessible to acids.
