heterocyclic compound

Any of a class of organic compounds whose molecules contain one or more rings of atoms with at least one atom (the heteroatom) being an element other than carbon, most frequently oxygen, nitrogen, or sulfur. As in regular cyclic hydrocarbons, such heterocyclic rings may include single, double, or triple bonds or be aromatic (see covalent bond; aromatic compound), and the compound may contain one or more single rings or have fused rings (in which adjoining rings share two carbon atoms). Compounds having five-membered heterocyclic rings include chlorophyll, hemoglobin, indigo, tryptophan, and certain polymers. Those with six-membered heterocyclic rings include pyridine, pyridoxine (vitamin B₆; see vitamin B complex), vitamin E, quinine, and the pyran nucleus, which is found in sugars and the anthocyanin pigments. Nicotine and morphine have both five- and six-membered heterocyclic rings; some antibiotics (e.g., penicillin) have two different heteroatoms in their rings. Other important heterocyclic compounds are pyrimidines, which occur in barbiturates, and purines, which occur in caffeine and related compounds; pyrimidine and purine are the parent compounds of the nucleic acids.

heterocyclic compound [‚hed·ə·rō′sī·klik ¦käm‚pau̇nd]

(organic chemistry)

Compound in which the ring structure is a combination of more than one kind of atom; for example, pyridine, C₅H₅N.

Mentioned in	?		References in periodicals archive	?		Encyclopedia browser	?		Full browser	?
No references found	Known as selective serotonin reuptake inhibitors (SSRIs), this radically new class of drugs offers distinct advantages over the older tricyclics, heterocyclics, and monoamine oxidase inhibitors. Don't take Prozac lightly by Medical Update	Heterocapsina heterocarpous heterocentric chromosome Heterocera heterocercal Heterocercal Fin Heteroceridae Heterocheilidae heterochlamydeous Heterochlorida heterochromatic photometry Heterochromatin heterochromia Heterochromous Photometry heterochronic mutation Heterochronism heterochrony heterochthonous Heteroclite heterococcolith heterocoelous Heterocorallia Heterocotylea heterocyclic compound Heterocyclic Compounds Heterocyclics heterocyst heterodactylous Heterodera heterodesmic heterodimer heterodisomy heterodont Heterodonta Heterodontoidea heterodox heteroduplex Heterodyne heterodyne analyzer heterodyne conversion transducer heterodyne detector heterodyne frequency heterodyne frequency meter heterodyne interference heterodyne measurement heterodyne modulator heterodyne oscillator heterodyne reception heterodyne repeater Heterodyne Resonance Indicator heterodyne wavemeter	heterocycle heterocycle heterocycle Heterocycles Heterocycles heterocyclic heterocyclic heterocyclic Heterocyclic Amine Heterocyclic Amine Heterocyclic amines Heterocyclic amines Heterocyclic Aromatic Amine Heterocyclic chemistry Heterocyclic chemistry heterocyclic compound heterocyclic compound heterocyclic compound Heterocyclic compounds Heterocyclic compounds Heterocyclic compounds with 4 or more rings Heterocyclic compounds with 4 or more rings Heterocyclic compounds, 1-ring Heterocyclic compounds, 1-ring Heterocyclic compounds, 2-ring Heterocyclic compounds, 2-ring Heterocyclic compounds, 3-ring Heterocyclic compounds, 3-ring heterocyclic ring heterocyclic ring Heterocyclics heterocyst heterocyst Heterocysts Heterocysts heterocytotropic heterocytotropic antibody heterodactyl heterodactyl foot Heterodactylae Heterodactylous Heterodactylous Heterodendrum oleifolium Heterodera heterodermic heterodermic heterodermic heterodermic heterodermic heterodermic graft heterodermic graft heterodermic graft heterodermic graft heterodermic graft heterodesmic heterodeviation heterodidymus Heterodimer Heterodimer Heterodimer Heterodimeric

Mentioned in

References in periodicals archive

Encyclopedia browser

Full browser

No references found

Known as selective serotonin reuptake inhibitors (SSRIs), this radically new class of drugs offers distinct advantages over the older tricyclics, heterocyclics, and monoamine oxidase inhibitors.

Don't take Prozac lightly by Medical Update

Heterocapsina

heterocarpous

heterocentric chromosome

heterochromatic photometry