Table of Contents
Introduction of pyrrole
Pyrrole is a heterocyclic aromatic compound that is commonly found in many natural products and pharmaceuticals. It is known to have important biological activities and is used in the synthesis of many useful drugs. Its presence in the environment makes it important in understanding the environmental chemistry as well as its effects on humans and other living beings. Pyrrole has been studied extensively, and its structure, physical properties, reactivity, pharmacological effects, and uses are all well documented. This article will provide an overview of pyrrole’s introduction, structure, properties and uses.
Pyrrole is one of the most essential five membered heterocyclic compound, containing nitrogen as a hetero atom. Its chemical formula is C4H5N and molecular weight is 67g/mol. It occurs naturally in alkaloids, chlorophyll, hemoglobin etc. (Introduction of pyrrole).
Chemistry of pyrrole
These are 3 pairs of delocalised pi-electron present in pyrrole out of which two pair represents the pi-bond, while the one pair represents the nonbonding electron present in the heteroatom. The aromaticity of the pyrrole is fulfilled by its structure, which indicates it as a cyclic planar molecule.
Properties of pyrrole
1. Pyrrole is liquids which radially turns brown an exposure to air.
2. Boiling point is 139°C.
3. It’s odour like that of chloroform.
4. It is sparingly soluble in water but dissolves in ethanol & ether.
5. It is weakly basic in nature.
Synthesis of pyrrole
1. From furan
It is prepared by passing the mixture of furan, ammonia and steam over the heated alumina ( aluminium oxide catalyst) at 400°C.
2. From succinimide
Succinimide in distillation with zinc dust give pyrrole.
3. From acetylene
Acetylene and ammonia are passed through red hot tube to yield pyrrole.
4. Paal Knorr synthesis(from 1,4-diketones)
In this reaction, 1,4-diketone compound react with ammonia and gives derivatives of pyrrole.
5. Knorr pyrrole synthesis
It involves the condensation of alpha-amino ketone derivatives with a Bita-keto ester in the presence of acetic acid.
Chemical reaction of pyrrole
These are some reactions of pyrrole
1. Nitration of pyrrole
In this reaction, pyrrole is reacted withal acetylnitrate in the presence of sulphuric acid to give 2-nitropyrrole.
2. Sulphonation of pyrrole
In this reaction, pyrrole is treated with sulphuric acid in the presence of pyrimidine to gives pyrrole-2-sulphonic acid.
3. Friedal craft reaction
In this reaction, pyrrole is reacted with acetic anhydride to give 2-acetylpyrrole.
4. Reduction reaction
In this reaction, pyrrole react with zinc and acetic acid to give 3-pyrroline. But on react with hydrogen in presence of nickel give pyrrolidine.
5. Oxidation reaction
In this reaction, pyrrole is oxidized with chromium trioxide in the presence of acetic acid to give maleimide.
Medicinal uses of pyrrole
1. Pyrrole & its derivatives are widely used as an intermediate in synthesis of pharmaceutical, medicines, agrochemicals, dyes, photographic chemical, perfumes & perfumes & another organic compound.
2. They are used as catalyst for polymerization process, corrosion inhibitors, preservatives and as solvents.
3. They are used as the standard of chromatographic analysis.
4. They are used in organic synthesis & the pharmaceutical industry.
Some derivatives and their medicinal uses
1. Procyclidine: It is an anti-muscarinic drug used in the treatment of parkinsonism.
2. Atorvastatin: It is useful to prevent cardiovascular disease.
3. Prodigiosin: It has antibacterial, antifungal, antimalaria and immunosuppressant activity.
4. Triprolidine: It is used as antihistamine.
5. Opipramol: It is used in antipsychotic drug.