- Also called:
- heterocycle
- Related Topics:
- propylene oxide
- benzimidazole
- pyridazine
- pteridine
- phenazine
heterocyclic compound
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What is a heterocyclic compound?
Heterocyclic compounds are a class of organic chemical compounds where atoms are joined in rings, with at least one atom being an element other than carbon. The term cyclic refers to the presence of a ring structure, while hetero- indicates the presence of noncarbon atoms (heteroatoms) within the ring.
Heterocyclic compounds are essential in many biochemical materials, such as nucleic acids, pigments, vitamins, and antibiotics. They are also used in synthetic drugs, pesticides, dyes, and plastics.
These compounds can be classified as saturated, unsaturated, or aromatic, influencing their chemical behavior. The synthesis of heterocyclic compounds involves various methods, including forming new heterocyclic rings from acyclic precursors or modifying substituents on existing rings.
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How is a heterocyclic compound different from a regular ring compound?
Heterocyclic compounds are a class of organic chemical compounds with molecules joined in rings containing at least one atom of an element other than carbon. These noncarbon atoms are also known as heteroatoms.
In contrast, regular ring compounds, also referred to as carbocyclic or alicyclic compounds, have only carbon atoms in the ring. Examples of carbocyclic compounds include cyclopropane and benzene.
The presence of heteroatoms gives heterocyclic compounds physical and chemical properties that are often quite distinct from those of their all-carbon-ring analogs.
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What types of atoms can be found in the ring of a heterocyclic compound?
A heterocyclic compound is a class of organic chemical compounds with a ring structure that contains at least one atom of an element other than carbon. The heteroatoms commonly found in these rings are nitrogen, oxygen, and sulfur. However, a wide variety of other elements can also form heterocyclic rings, including silicon, germanium, tin, lead, chlorine, bromine, iodine, selenium, and tellurium.
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What are some examples of heterocyclic compounds?
Heterocyclic compounds are organic compounds with ring structures that contain at least one atom of an element other than carbon. These non-carbon atoms are also known as heteroatoms.
Examples of heterocyclic compounds:
* Pyrrolidine A saturated heterocyclic compound
* Pyridine A heteroaromatic substance
* Furan The simplest member of the furan family of oxygen heterocycles
* Thiazoles This ring system occurs in thiamin (thiamine, vitamin B1), the bacitracin and penicillin antibiotics, and in numerous synthetic drugs, dyes, and industrial chemicals
* Purine The purine structure is present in many natural substances. Two purine nucleotide bases, adenine and guanine, occur together with the pyrimidine bases in DNA and RNA1 Britannica SourceCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
Why are heterocyclic compounds important in biology and medicine?
Heterocyclic compounds are essential in biology and medicine due to their unique chemical properties and presence in crucial biomolecules. These compounds, characterized by rings containing carbon and at least one other element, are building blocks for nucleic acids (DNA and RNA) that carry genetic information.
Many natural pigments, antibiotics, and vitamins are heterocyclic. For instance, Vitamin B12 has a benzimidazole unit, and Vitamin B1 (thiamine) contains a thiazole ring.
Modern medicine relies on synthetic heterocycles in drugs like antihistamines, anti-inflammatory drugs, and antiepileptics. They also appear in dyes, pesticides, and plastics. Certain compounds, such as those found in crown ethers, can selectively bind metal ions, which has led to applications in medical diagnostics and environmental testing.
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How are heterocyclic compounds used in making pharmaceuticals or other useful products?
Heterocyclic compounds are essential in many biochemical materials and are also important in the creation of synthetic materials. They are used in a variety of applications:
- Pharmaceuticals Many modern drugs utilize synthetic heterocycles. For example, aziridine derivatives are used to treat cancer. Also, oxetanes are being studied as anti-inflammatory and antiviral agents.
- Plastics Polymers and copolymers of oxirane and aziridine are useful plastics.
- Other Useful Products Crown ethers are used in medical diagnostics and for separating radioactive isotopes. Caprolactam, an azepine derivative, is used to make nylon-6, films, coatings, and synthetic leather.
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heterocyclic compound, any of a major class of organic chemical compounds characterized by the fact that some or all of the atoms in their molecules are joined in rings containing at least one atom of an element other than carbon (C). The cyclic part (from Greek kyklos, meaning “circle”) of heterocyclic indicates that at least one ring structure is present in such a compound, while the prefix hetero- (from Greek heteros, meaning “other” or “different”) refers to the noncarbon atoms, or heteroatoms, in the ring. In their general structure, heterocyclic compounds resemble cyclic organic compounds that incorporate only carbon atoms in the rings—for example, cyclopropane (with a three-carbon-atom ring) or benzene (with a six-carbon-atom ring)—but the presence of the heteroatoms gives heterocyclic compounds physical and chemical properties that are often quite distinct from those of their all-carbon-ring analogs.
Heterocyclic compounds include many of the biochemical material essential to life. For example, nucleic acids, the chemical substances that carry the genetic information controlling inheritance, consist of long chains of heterocyclic units held together by other types of materials. Many naturally occurring pigments, vitamins, and antibiotics are heterocyclic compounds, as are most hallucinogens. Modern society is dependent on synthetic heterocycles for use as drugs, pesticides, dyes, and plastics.
General aspects of heterocyclic compounds
The most common heterocycles are those having five- or six-membered rings and containing heteroatoms of nitrogen (N), oxygen (O), or sulfur (S). The best known of the simple heterocyclic compounds are pyridine, pyrrole, furan, and thiophene. A molecule of pyridine contains a ring of six atoms—five carbon atoms and one nitrogen atom. Pyrrole, furan, and thiophene molecules each contain five-membered rings, composed of four atoms of carbon and one atom of nitrogen, oxygen, or sulfur, respectively.
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Pyridine and pyrrole are both nitrogen heterocycles—their molecules contain nitrogen atoms along with carbon atoms in the rings. The molecules of many biological materials consist in part of pyridine and pyrrole rings, and such materials yield small amounts of pyridine and pyrrole upon strong heating. In fact, both of these substances were discovered in the 1850s in an oily mixture formed by strong heating of bones. Today, pyridine and pyrrole are prepared by synthetic reactions.Their chief commercial interest lies in their conversion to other substances, chiefly dyestuffs and drugs. Pyridine is used also as a solvent, a waterproofing agent, a rubber additive, an alcohol denaturant, and a dyeing adjunct.
Furan is an oxygen-containing heterocycle employed primarily for conversion to other substances (including pyrrole). Furfural, a close chemical relative of furan, is obtained from oat hulls and corncobs and is used in the production of intermediates for nylon. Thiophene, a sulfur heterocycle, resembles benzene in its chemical and physical properties. It is a frequent contaminant of the benzene obtained from natural sources and was first discovered during the purification of benzene. Like the other compounds, it is used primarily for conversion to other substances. Furan and thiophene were both discovered in the latter part of the 19th century.
In general, the physical and chemical properties of heterocyclic compounds are best understood by comparing them with ordinary organic compounds that do not contain heteroatoms.