In a similar fashion, they can be created from 1,4 diketones in the Paal-Knorr synthesis, and three-four substituted ones are formed in the Piloty-Robinson synthesis.
These compounds can be created from alpha amino-ketones and from compounds containing a methylene group alpha-bonded to a carbonyl group in the Knorr synthesis. In a similar fashion, they can be created from 1,4 diketones in the Paal-Knorr synthesis, and three-four substituted ones are formed in the Piloty-Robinson synthesis. Also created by the Hantzch synthesis, their chemistry was investigated by Hans Fischer, and they are components of biological macromolecules including chlorophyll and heme. It is very similar in structure to thiophene and furan, except that its non-carbon atom is not sulfur or oxygen, but rather nitrogen. FTP, name this heterocyclic aromatic compound, a five-membered ring with two double bonds containing four carbons and one nitrogen atom.
These compounds can be created from alpha amino-ketones and from compounds containing a methylene group alpha-bonded to a carbonyl group in the Knorr synthesis.
pyrrole