Definitions containing s10-membered
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Cyclodextrins are a family of compounds made up of sugar molecules bound together in a ring. Cyclodextrins are produced from starch by means of enzymatic conversion. They are used in food, pharmaceutical, drug delivery, and chemical industries, as well as agriculture and environmental engineering. Hydroxypropyl Beta Cyclodextrin is the chief active compound found in Procter and Gamble's deodorizing product "Febreze" under the brand name "Clenzaire". Cyclodextrins are composed of 5 or more α-D-glucopyranoside units linked 1->4, as in amylose. The 5-membered macrocycle is not natural. Recently, the largest well-characterized cyclodextrin contains 32 1,4-anhydroglucopyranoside units, while as a poorly characterized mixture, at least 150-membered cyclic oligosaccharides are also known. Typical cyclodextrins contain a number of glucose monomers ranging from six to eight units in a ring, creating a cone shape: ⁕α -cyclodextrin: 6-membered sugar ring molecule ⁕β -cyclodextrin: 7-membered sugar ring molecule ⁕γ -cyclodextrin: 8-membered sugar ring molecule
Compounds based on a seven-membered ring fused to a five-membered ring. Heat can rearrange them to NAPHTHALENES which have two fused six-membered rings. They are similar to guaiazulenes which are SESQUITERPENES with a six-membered ring fused to a five-membered ring.
— U.S. National Library of Medicine
Oxindole is an aromatic heterocyclic organic compound. It has a bicyclic structure, consisting of a six-membered benzene ring fused to a five-membered nitrogen-containing ring. The compound's structure is based on the indoline structure but where a carbonyl is situated at the 2-position of the 5 membered ring.
Isoindoline is a heterocyclic organic compound with the molecular formula C8H9N. It has a bicyclic structure, consisting of a six-membered benzene ring fused to a five-membered nitrogen-containing ring. The compound's structure is similar to indoline except that the nitrogen atom is in the 2 position instead of the 1 position of the five-membered ring.
Carbazole is an aromatic heterocyclic organic compound. It has a tricyclic structure, consisting of two six-membered benzene rings fused on either side of a five-membered nitrogen-containing ring. The compound's structure is based on the indole structure but in which a second benzene ring is fused onto the five-membered ring at the 2–3 position of indole.
An Atrane is a tricyclic molecule with three five-membered rings. It has a transannular dative bond by a nitrogen atom, depicted as A. The name "atrane" was first proposed by Mikhail Grigorievich Voronkov. Various atranes are named depending on the central element, e.g. "silatrane"; "boratrane"; "phosphatrane", etc. It is also proposed that when Y = nitrogen, the prefix "aza" be inserted before element + "atrane" because atranes wherein E = silicon and Y = oxygen have been referred to as just "silatranes". Silatranes exhibit unusual properties as well as biological activity in which the coordination of nitrogen to silane plays an important role. Some derivatives such as phenylsilatrane are highly toxic. The transannular coordinate bond in atranes can be stretched and even broken by controlling their stereoelectronic properties. Proazaphosphatrane is a very strong non-ionic base and is utilized in various types of organic synthesis as an efficient catalyst. In 2000, Robert R. Holmes and his co-workers reported a new class of silatranes that contain three six-membered rings and revealed that these atranes have weaker nitrogen donor interaction in comparison with corresponding ones bearing three five-membered rings. The degree of the interaction depends mainly on the electronegativity effects of an exocyclic ligand.
any of three isomeric compounds having three carbon and three nitrogen atoms in a six-membered ring
— Princeton's WordNet
A cyclic organic peroxide; a mixture of mostly the trimer, (((CH)CO)), (TCAP or TATP), containing a nine-membered ring and the dimer, (((CH)CO)) containing a six-membered ring; it is a high explosive manufactured from acetone and hydrogen peroxide with the aid of sulphuric acid, and has been used by amateur bomb makers.
any mancude assembly of three carbocyclic rings having a six-membered quinonoid ring bonded (in the 1,4 positions) to two odd-membered rings whose size differs by two
A bicyclic heterocycle containing a six-membered ring fused to a five-membered ring, one of the bridging atoms being nitrogen; any derivative of this compound, especially several alkaloids
Indoline is an aromatic heterocyclic organic compound. It has a bicyclic structure, consisting of a six-membered benzene ring fused to a five-membered nitrogen-containing ring. The compound is based on the indole structure, but the 2-3 bond is saturated. By oxidation/dehydrogenation it can be converted to indoles.
In chemistry, pyran, or oxine, is a six-membered heterocyclic, non-aromatic ring, consisting of five carbon atoms and one oxygen atom and containing two double bonds. The molecular formula is C5H6O. There are two isomers of pyran that differ by the location of the double bonds. In 2H-pyran, the saturated carbon is at position 2, whereas, in 4H-pyran, the saturated carbon is at position 4. 4H-Pyran was first isolated and characterized in 1962 via pyrolysis of 2-acetoxy-3,4-dihydro-2H-pyran. It was found too unstable, particularly in the presence of air. 4H-pyran easily disproportionates to the corresponding dihydropyran and the pyrylium ion, which is easily hydrolyzed in aqueous medium. Although the pyrans themselves have little significance in chemistry, many of their derivatives are important biological molecules, such as the pyranoflavonoids. The term pyran is also often applied to the saturated ring analog, which is more properly referred to as tetrahydropyran. In this context, the monosaccharides containing a six-membered ring system are known as pyranoses.
Indole is an aromatic heterocyclic organic compound. It has a bicyclic structure, consisting of a six-membered benzene ring fused to a five-membered nitrogen-containing pyrrole ring. Indole is a common component of fragrances and the precursor to many pharmaceuticals. Compounds that contain an indole ring are called indoles. The amino acid tryptophan is an indole derivative and the precursor of the neurotransmitter serotonin.
An aromatic hydrocarbon or arene is a hydrocarbon with alternating double and single bonds between carbon atoms forming rings. The term 'aromatic' was assigned before the physical mechanism determining aromaticity was discovered, and was derived from the fact that many of the compounds have a sweet scent. The configuration of six carbon atoms in aromatic compounds is known as a benzene ring, after the simplest possible such hydrocarbon, benzene. Aromatic hydrocarbons can be monocyclic or polycyclic. Some non-benzene-based compounds called heteroarenes, which follows Hückel's rule, are also called as aromatic compounds. In these compounds, at least one carbon atom is replaced by one of the heteroatoms oxygen, nitrogen, or sulfur. Examples of non-benzene compounds with aromatic properties are furan, a heterocyclic compound with a five-membered ring that includes an oxygen atom, and pyridine, a heterocyclic compound with a six-membered ring containing one nitrogen atom.
Boron trioxide is one of the oxides of boron. It is a nonlethal toxic white, glassy solid with the formula B2O3. It is almost always found as the vitreous form; however, it can be crystallized after extensive annealing. It is known as one of the most difficult compounds to crystallize. Glassy boron oxide is thought to be composed of boroxol rings which are six-membered rings composed of alternating 3-coordinate boron and 2-coordinate oxygen. This view is controversial, however, because no model has ever been made of glassy boron oxide of the correct density containing a large number of six-membered rings. The rings are thought to make a few BO3 triangles, but mostly link into ribbons and sheets. The crystalline form is exclusively composed of BO3 triangles. This trigonal, quartz-like network undergoes a coesite-like transformation to monoclinic β-B2O3 at several gigapascals.
Muscone is an organic compound that is the primary contributor to the odor of musk. The chemical structure of muscone was first elucidated by Lavoslav Ružička. It consists of a 15-membered ring ketone with one methyl substituent in the 3-position. It is an oily liquid that is found naturally as the-enantiomer, but synthetic material is typically a racemate. It is very slightly soluble in water and miscible with alcohol. Natural muscone is obtained from musk, a glandular secretion of the musk deer, which has been used in perfumery and medicine for thousands of years. Since obtaining natural musk requires killing the endangered animal, nearly all muscone used in perfumery today is synthetic. It has the characteristic smell of being "Musky". One asymmetric synthesis of-muscone begins with commercially available-citronellal, and forms the 15-membered ring via ring-closing metathesis: Muscone is now produced synthetically for use in perfumes and for scenting consumer products.
any of a class of chemical substances, some of which have therapeutically useful antibacterial activity, whose structure contains a beta-lactam ring fused to a six-membered ring containing a sulfur and a nitrogen atom. The first of the series, cephalosporin C, was discovered by G. Brotzu in 1955 in the culture broth of a Cephalosporium species found off the coast of Sardinia. Other cephalosporins have been found to be produced by species of soil bacteria (actinomycetes). Many semisynthetic analogs have been tested for antibacterial effect, and several of them have found use as important clinically useful antibacterial agents, some of which may be taken orally for treatment of bacterial infections. The cephalosporins are the second class of beta-lactam antibiotic to be discovered, the first being the penicillins and more recent classes being the thienamycins and sulfazecins. The cephamycins are a variant of cephalosporins with a methoxyl group on the beta-lactam ring, rendering them more resistant to penicillinases. Among the cephalosporins which have been found clinically useful are cephalexin, cephaloridine, and cephalothin.
A peculiar hydrocarbon fraction occuring as an ingredient of some crude petroleums, mostly mixtures of derivatives of the five- and six-membered saturated cyclic alkanes, cyclopentane and cyclohexane, having the general formula CnH2n.
An unsaturated, five-membered heterocyclic compound of arsenic, CHAs; any substituted form of this compound
Any six-membered aromatic heterocycle containing four carbon atoms, two nitrogen atoms and three double bonds
Any of a class of organic compound, cyclic ethers, having a three-membered ring; they are prepared by the selective oxidation of alkenes or by ring-closure of halohydrins; used to make plastics.
a class of heterocyclic compounds having a four-membered ring containing 3 carbon atoms and 1 oxygen atom; the parent compound CHO
any of a class of aromatic compounds having two carbonyl functional groups in the same six-membered ring
any of a class of compounds having five-membered ring heterocycles (or their benzo derivatives) which possess a sextet of u03C0-electrons in association with the atoms comprising the ring, but which cannot be represented by any one covalent or polar structure; typically the ring structure contains both positive and negative delocalised charges which cannot be associated with any one ring atom, and the negative charge can also be associated with a conjugated exocyclic atom (typically oxygen, sulfur, or nitrogen).
A lactam having a three-membered ring structure.
A lactam having a four-membered ring structure; a structural element of many antibiotics such as penicillin.
any of a class of heterocyclic amines having a saturated five-membered ring; especially the parent compound of this class, CHN
Any of three isomeric monounsaturated heterocycles having a five-membered ring and one nitrogen atom CHN; any derivative of these compounds
A five-membered, saturated heterocycle, containing two carbon atoms and three oxygen atoms; any derivative of this compound
Any of a class of organic compounds formed by the cyclization of N-acyl-u03B1-amino acids; they are five-membered heterocycles containing both a nitrogen and oxygen atom in the ring, with the oxygen adjacent to a carbonyl.
the unsaturated six-membered heterocycle having four carbon atoms, two oxygen atoms and two double bonds
any cyclic hemiacetal form of a monosaccharide having a five-membered ring (the tetrahydrofuran skeleton)
either of two isomeric heterocyclic compounds having a five-membered ring with three nitrogen atoms and two double bonds in the ring; any organic derivative of these compounds
Any polycyclic saturated hydrocarbon consisting of fused five-membered rings.
any polycyclic unsaturated hydrocarbon consisting of fused five-membered rings
a heterocyclic ether having a five-membered ring with four carbon atoms and one carbon; it is a colourless liquid with an ether-like smell, and is used as a polar solvent
any cyclic hemiacetal form of a monosaccharide having a six-membered ring (based on tetrahydropyran)
a six-membered heterocyclic ether having five carbon atoms and one oxygen; the core structure of pyranose sugars
an allotropic form of carbon consisting of a low-density, three-dimensional web of graphene plates, distorted by the inclusion of some seven-membered rings
An electrically conducting polymer in which the repeat units are azulene molecules linked through the five-membered ring.
A bicyclic aromatic hydrocarbon containing a five- and a seven-membered fused ring; it is a blue, oily liquid first obtained from the essential oil of wormwood.
A heterocyclic organic compound containing two nitrogen atoms separated by a carbon atom in a five-membered ring, called 1,3-diazole in w:IUPAC nomenclature.
Any of a class of six-membered, saturated heterocycles having four carbon atoms and two oxygen atoms in the ring
A saturated heterocyclic compound, CHN, containing two nitrogen atoms in a six-membered ring; it is used as an anthelmintic.
Any of a class of drugs, used to treat diabetes, containing a five-membered heterocyclic ring containing a nitrogen and a sulfur atom and two carbonyl groups.
A three-membered heterocycle containing two methylene groups and an imine; the nitrogen equivalent of ethylene oxide.
A seven-membered unsaturated heterocycle having two nitrogen atoms and three double bonds; any derivative of this compound
A bicyclic aromatic heterocycle containing a benzene ring fused with five-membered cyclic amide
Any of a class of five-membered, saturated heterocycles containing two carbon atoms, a nitrogen, boron and oxygen atom
An unsaturated heterocyclic compound containing a five-membered ring, one double bond, one nitrogen and one sulfur atom; any derivative of this compound
An unsaturated heterocyclic compound containing a five-membered ring, one double bond, one nitrogen and one oxygen atom; any derivative of this compound
Any of several isomeric non-aromatic bicyclic heterocycles, of formula CHN, having two six-membered rings with the nitrogen atom as one of the bridge atoms; any of very many known derivatives of these compounds
Any of a class of five-membered unsaturated heterocycles having three carbon atoms, one nitrogen atom and two double bonds
Having a specified number of members; e.g. a five-membered ring
A saturated, five-membered heterocycle containing one atom of sulfur; it is added to natural gas to provide it with a detectable smell
Any of several isomeric five-membered heterocycles having one nitrogen atom, two phosphorus atoms and two double bonds
A five-membered saturated heterocycle containing three carbon atoms, an oxygen atom and a hypervalent iodine atom; its derivatives (especially the benziodoxols) are used as pharmaceuticals etc
Any of four isomeric tricyclic heterocycles consisting of a pyridine ring fused with the five-membered ring of an indole; many of their derivatives have biological action
A cycloalkene with a four-membered ring and one double bond.
A cycloalkene having a seven-membered ring and three double bonds; removal of a hydride ion produces the aromatic tropylium ion
Any of several isomers of a cycloalkene having an eight-membered ring and two double bonds, but especially 1,5-cyclooctadiene that is used as a ligand in organometallic chemistry
A cycloalkene having an eight-membered ring and alternating single and double bonds; being nonplanar, it is not aromatic
The unsaturated heterocycle consisting of a three-membered ring containing one carbon atom and two nitrogen atoms connected by a double bond; it is isomeric with diazomethane
Either of two unsaturated heterocycles consisting of a five-membered ring containg three carbon atoms, two nitrogen atoms and two double bonds - namely pyrazole and imidazole
A heterocyclic organic compound containing two nitrogen atoms next to each others in a five-membered ring, called 1,2-diazole in w:IUPAC nomenclature.
Any of a class of heterocycle having a four-membered ring with two carbon atoms and two oxygen atoms
Any heterocycle having a five-membered ring with three carbon atoms and two oxygen atoms
Any five-membered heterocycle having two carbon atoms, two nitrogen atoms, one oxygen atom, and two double bonds
A five-membered heterocycle containing three carbon atoms, two non-adjacent nitrogen atoms and one double bond
A five-membered heterocycle having three carbon atoms, one oxygen atom, one nitrogen atom and two double bonds; the 1,3- isomer is aromatic
A six membered, saturated heterocycle tetrahydro-1,4-oxazine containing four carbon atoms, one nitrogen and one oxygen atom; it has a number of industrial applications
Any of three isomeric six-membered saturated heterocycles containing four carbon atoms, one oxygen and one sulfur atom
Any unsaturated six-membered heterocycle containing four carbon atoms, one oxygen, one nitrogen atom and two double bonds
The unsaturated seven-membered heterocycle containing six carbon atoms, one oxygen atom and three double bonds; it is tautomeric with the epoxide benzene oxide
The five-membered homocyclic compound containing five nitrogen atoms and two double bonds
A six-membered heterocycle containing four carbon atoms, one nitrogen and one sulfur atom, and two double bonds; many of its derivatives have important applications
Any six-membered heterocycle having two carbon atoms, four nitrogen atoms and three double bonds
A five-membered heterocycle having one carbon atom, four nitrogen atoms and two double bonds
Any of a class of hydrocarbons consisting of spiro-linked cyclopropane units only, but with a common [n]membered ring in the middle; they are named n-rotanes depending on the size of the inner ring
A five-membered heterocycle having four carbon atoms, one silicon atom and two double bonds; it is analogous to cyclopentadiene
A six-membered saturated heterocycle having two carbon atoms and four oxygen atoms; especially the isomer having two peroxide groups (as in the acetone peroxide dimer)
Any of several isomeric five-membered heterocycles having two carbon atoms, two nitrogen atoms, one sulfur atom and two double bonds
Any of several isomeric five-membered heterocycles having two carbon atoms, two nitrogen atoms, one sulfur atom and one double bond
Any of several isomeric five-membered heterocycles having one carbon atoms, three nitrogen atoms, one sulfur atom and two double bonds
Any of several isomeric five-membered heterocycles having one carbon atoms, three nitrogen atoms, one sulfur atom and one double bond
The saturated three-membered heterocycle containing two carbon atoms and one sulfur atom; ethylene sulfide
Any saturated six-membered heterocycle having three carbon atoms and three oxygen atoms
A polycyclic aromatic hydrocarbon containing an unsaturated five-membered ring ortho- and peri-fused to the 1- and 9- positions of anthracene
A polycyclic aromatic hydrocarbon containing an unsaturated five-membered ring ortho- and peri-fused to the 1- and 9- positions of naphthalene.
A polycyclic aromatic hydrocarbon containing an unsaturated five-membered ring ortho- and peri-fused to the 1- and 9- positions of phenanthrene
A saturated seven-membered heterocycle having six carbon atoms and one nitrogen atom
An unsaturated seven-membered heterocycle having six carbon atoms, one nitrogen atom and three double bonds
An unsaturated seven-membered heterocycle having six carbon atoms, one oxygen atom and three double bonds
A saturated seven-membered heterocycle having six carbon atoms and one oxygen atom
An unsaturated seven-membered heterocycle having six carbon atoms, one sulfur atom and three double bonds
A saturated seven-membered heterocycle having six carbon atoms and one sulfur atom
A saturated eight-membered heterocycle having seven carbon atoms and one nitrogen atom
An unsaturated eight-membered heterocycle having seven carbon atoms, one nitrogen atom and four double bonds
An unsaturated eight-membered heterocycle having seven carbon atoms, one oxygen atom and three double bonds
A saturated eight-membered heterocycle having seven carbon atoms and one oxygen atom
A saturated eight-membered heterocycle having seven carbon atoms and one sulfur atom
An unsaturated eight-membered heterocycle having seven carbon atoms, one sulfur atom and three double bonds
An unsaturated six-membered heterocycle consisting of five carbon atoms. one sulfur atom and two double bonds
An unsaturated six-membered heterocycle having three carbon atoms, one oxygen atom, two nitrogen atoms and two double bonds
An unsaturated five-membered heterocycle having three carbon atoms, one oxygen atom, one sulfur atom and one double bond
An unsaturated ten-membered heterocycle having eight carbon atoms, two nitrogen atoms and five double bonds
The unsaturated six-membered heterocycle containing four carbon atoms, two sulfur atoms and two double bonds
The unsaturated five-membered heterocycle having three carbon atoms, one oxygen atom, one phosphorus atom and two double bonds.
The unsaturated five-membered heterocycle having four carbon atoms, one phosphorus atom and two double bonds; an analogue of pyrrole
The unsaturated five-membered heterocycle having two carbon atoms, one oxygen atom, one sulfur atom, one nitrogen atom and one double bond
The unsaturated six-membered heterocycle having four carbon atoms, one oxygen atom, one sulfur atom and two double bonds
The unsaturated three-membered heterocycle having two carbon atoms, one oxygen atom and one double bond
The unsaturated nine-membered heterocycle having eight carbon atoms, one oxygen atom and four double bonds
The six-membered aromatic heterocycle containing four carbon atoms, one nitrogen atom and one arsenic atom
The six-membered aromatic heterocycle containing four carbon atoms, one nitrogen atom and one phosphorus atom
The six-membered unsaturated heterocycle containing four carbon atoms, one oxygen atom, one phosphorus atom and two double bonds
The unsaturated three-membered heterocycle containing two carbon atoms, one sulfur atom and a double bond.
Any monosaccharide having the configuration of an eight-membered ring
Any monosaccharide having a configuration with a four-membered ring
Any monosaccharide having a configuration with a three-membered ring
Any monosaccharide having a configuration containing a seven-membered ring
A five-membered unsaturated heterocycle containing three carbon atoms, one nitrogen and oxygen atoms (adjacent) and a carbon-nitrogen double bond
A five-membered saturated heterocycle having a three carbon atoms, one oxygen atom and one sulfur atom
A three-membered heterocycle having two carbon atoms and one oxygen atom; ethylene oxide
A five-membered saturated heterocyclic ketone having one nitrogen atom, one oxygen atom and two carbonyl groups
The five-membered, unsaturated heterocyclic ketone having four nitrogen atoms and one double bond opposite the carbonyl group
A five-membered unsaturated heterocyclic ketone having three nitrogen atoms, one double bond and a carbonyl group
Any reactive intermediate in the form of a three-membered unsaturated cyclic cation containing a positively charged halogen atom
Any of a class of unstable heterocycles containing three successive oxygen atoms in a five-membered ring; the 1,2,3-trioxolanes
Any of a class of cyclic chemical compounds that contain an unsaturated six-membered ring with one oxygen atom and a ketone functional group.
A saturated five-membered heterocycle containing three carbon atoms and two nitrogen atoms
A saturated, five-membered heterocycle containing three carbon atoms and a sulfur and nitrogen atom in the 1,2 positions; any derivative of this compound
A saturated, five-membered heterocycle containing three carbon atoms and a sulfur and nitrogen atom in the 1,3 positions; any derivative of this compound
Any of a class of saturated heterocycles having a three-membered ring, one carbon atom and two oxygen atoms
Any of a class of saturated heterocycles having a four-membered ring, three carbon atoms and one sulfur atom
Any of a class of heterocycle having a four-membered ring with two carbon atoms and two sulfur atoms
The five-membered saturated heterocycle having four carbon atoms and one sulfur atom; any derivative of this compound
Any of a class of bacterial products characterized by nine- or ten-membered rings containing two triple bonds separated by a double bond, many of which are highly toxic to DNA and used as antitumour agents.
the most stable chemical conformation of a six membered single bonded carbon ring like cyclohexane
A six-membered saturated heterocycle containing three carbon atoms, two nitrogen atoms and one oxygen atom; any derivative of this compound
A six-membered saturated heterocycle containing four carbon atoms and two nitrogen atoms; any derivative of this compound
A five-membered unsaturated heterocycle containing two carbon atoms, one sulfur atom, two nitrogen atoms and one double bond; any derivative of this compound
The six-membered aromatic heterocycle containing three carbon atoms and three nitrogen atoms arranged alternately; any derivative of this compound
A seven-membered heterocycle containing five carbon atoms, two oxygen atoms and two double bonds
The five-membered unsaturated heterocycle consisting of three carbon atoms, one oxygen atom, one hypervalent iodine atom and one double bond; any derivative of this compound
A seven-membered unsaturated heterocycle containing five carbon atoms, one nitrogen and one oxygen atom, and three double bonds; any derivative of this compound
Any six-membered unsaturated heterocycle containing four carbon atoms, one oxygen and one nitrogen atoms and one double bond
Any of three isomeric six-membered saturated heterocycles having three carbon atoms and three sulfur atoms; any derivative of these compounds
Any of three isomeric six-membered saturated heterocycles having four carbon atoms and two sulfur atoms; any derivative of these compounds
A saturated, four-membered heterocycle containing two carbon atoms, one oxygen atom and one nitrogen atom; any derivative of this compound
A seven-membered unsaturated heterocycle containing six carbon atoms, one phosphorus atom and three double bonds; any derivative of this compound
A saturated, five-membered heterocycle having two carbon atoms, two nitrogen atoms and one phosphorus atom; any derivative of this compound
A saturated, five-membered heterocycle having four carbon atoms and one phosphorus atom; any derivative of this compound
A five-membered, unsaturated heterocycle having four carbon atoms, one oxygen atom and one double bond; any derivative of this compound
An unsaturated, five-membered heterocycle containing four carbon atoms, one sulfur atom and one double bond; any derivative of this compound
A five-membered heterocycle containing three carbon atoms, two adjacent nitrogen atoms and one double bond
Any of three isomeric, six-membered, unsaturated heterocycles having five carbon atoms, one nitrogen atom and one double bond; any derivative of these compounds
Any of several isomeric five-membered saturated heterocycles having two carbon atoms, one boron atom and two oxygen atoms; any derivative of this compound
A five-membered, saturated heterocycle having two carbon atoms, and one each of nitrogen, sulfur and oxygen; any derivative of this compound
A saturated four-membered heterocycle having two carbon atoms, one silicon and one oxygen atom; any of its derivatives
A five-membered saturated heterocycle having two carbon atoms, two nitrogen atoms and a boron atom; any derivative of this compound
An unsaturated five-membered heterocycle having two carbon atoms, three nitrogen atoms and one double bond (between two of the nitrogen atoms); any derivative of this compound
A five-membered unsaturated heterocyclic ketone (or lactam), derived from pyrazole, that is the basis of several pharmaceuticals
A six-membered aromatic heterocyclic cation containing five carbon atoms and an oxygen atom that carries a positive charge; any derivative of this compound
Any of several isomeric seven-membered, unsaturated heterocycles containing four carbon atoms, two nitrogen atoms, one oxygen atoms and three double bonds
Any of several isomeric seven-membered, unsaturated heterocycles containing four carbon atoms, two nitrogen atoms, one sulfur atom and three double bonds
A seven-membered unsaturated heterocycle having three nitrogen atoms and three double bonds; any derivative of this compound
Any of four isomeric, saturated, eight-membered heterocycles having six carbon atoms and two oxygen atoms
Any of four isomeric, saturated, eight-membered heterocycles having six carbon atoms and two sulfur atoms
An unsaturated, five-membered heterocycle containing two sulfur atoms, one nitrogen atom and two double bonds
An unsaturated four-membered heterocycle containing three carbon atoms, one nitrogen atom and two double bonds
Oxetane, or 1,3-propylene oxide, is an heterocyclic organic compound with the molecular formula C3H6O, having a four-membered ring with three carbon atoms and one oxygen atom. The term oxetane may also refer more generally to any organic compound containing an oxetane ring.
Triazole refers to either one of a pair of isomeric chemical compounds with molecular formula C2H3N3, having a five-membered ring of two carbon atoms and three nitrogen atoms. The two isomers are: ⁕1,2,3-Triazole ⁕1,2,4-Triazole
Tetrazine is an unstable compound that consists of a six-membered aromatic ring containing four nitrogen atoms with the molecular formula C2H2N4. The name tetrazine is used in the nomenclature of derivatives of this compound. Three core-ring isomers exist: 1,2,3,4-tetrazines, 1,2,3,5-tetrazines and 1,2,4,5-tetrazines.
Pyrones or pyranones are a class of cyclic chemical compounds. They contain an unsaturated six membered ring containing one oxygen atom and a ketone functional group. There are two isomers denoted as 2-pyrone and 4-pyrone. The 2-pyrone structure is found in nature as part of the coumarin ring system. 4-Pyrone is found in some natural chemical compounds such as chromone, maltol and kojic acid.
HMX, also called octogen, is a powerful and relatively insensitive nitroamine high explosive, chemically related to RDX. Like RDX, the compound's name is the subject of much speculation, having been variously listed as High Melting eXplosive, Her Majesty's eXplosive, High-velocity Military eXplosive, or High-Molecular-weight rdX. The molecular structure of HMX consists of an eight-membered ring of alternating carbon and nitrogen atoms, with a nitro group attached to each nitrogen atom. Because of its high molecular weight, it is one of the most potent chemical explosives manufactured, although a number of newer ones, including HNIW and ONC, are more powerful.
Mordenite is a zeolite mineral with the chemical formula, Al2Si10O24·7H2O. According to Ullmann's Encyclopedia of Industrial Chemistry, it is one of the six most abundant zeolites and is used commercially. It was first described in 1864 by Henry How. He named it after the small community of Morden, Nova Scotia, Canada, along the Bay of Fundy, where it was first found. Mordenite is orthorhombic. It crystallizes in the form of fibrous aggregates, masses, and vertically striated prismatic crystals. It may be colorless, white, or faintly yellow or pink. It has Mohs hardness of 5 and a density of 2.1 g/cm³. When it forms well developed crystals they are hairlike; very long, thin, and delicate. Mordenite’s molecular structure is a framework containing chains of five-membered rings of linked silicate and aluminate tetrahedra. Its high ratio of silicon to aluminum atoms makes it more resistant to attack by acids than most other zeolites. Mordenite is one of the most abundant zeolites in altered volcanic deposits; it is found in volcanic rock such as rhyolite, andesite, and basalt. It is associated with other zeolites such as stilbite and heulandite. Good examples have been found in Iceland, India, Italy, Oregon, Washington, and Idaho. It is also found in marine sediments, as in the Ural Mountains and in dikes where water has attacked and altered volcanic glasses, as on the Isle of Arran in Scotland.
An azole is a class of five-membered nitrogen heterocyclic ring compounds containing at least one other non-carbon atom of either nitrogen, sulfur, or oxygen. The parent compounds are aromatic and have two double bonds; there are successively reduced analogs with fewer. One, and only one, lone pair of electrons from each heteroatom in the ring is part of the aromatic bonding in an azole. Names of azoles maintain the prefix upon reduction. The numbering of ring atoms in azoles starts with the heteroatom that is not part of a double bond, and then proceeds towards the other heteroatom.
Erythromycin is a macrolide antibiotic that has an antimicrobial spectrum similar to or slightly wider than that of penicillin, and is often prescribed for people who have an allergy to penicillins. For respiratory tract infections, it has better coverage of atypical organisms, including Mycoplasma and legionellosis. It was first marketed by Eli Lilly and Company, and it is today commonly known as EES. It is also occasionally used as a prokinetic agent. In structure, this macrocyclic compound contains a 14-membered lactone ring with ten asymmetric centers and two sugars, making it a compound very difficult to produce via synthetic methods. Erythromycin is produced from a strain of the actinomycete Saccharopolyspora erythraea.
In organic chemistry, aromaticity is a chemical property describing the way in which a conjugated ring of unsaturated bonds, lone pairs, or empty orbitals exhibits a stabilization stronger than would be expected by the stabilization of conjugation alone. The earliest use of the term was in an article by August Wilhelm Hofmann in 1855. There is no general relationship between aromaticity as a chemical property and the olfactory properties of such compounds. Aromaticity can also be considered a manifestation of cyclic delocalization and of resonance. This is usually considered to be because electrons are free to cycle around circular arrangements of atoms that are alternately single- and double-bonded to one another. These bonds may be seen as a hybrid of a single bond and a double bond, each bond in the ring identical to every other. This commonly seen model of aromatic rings, namely the idea that benzene was formed from a six-membered carbon ring with alternating single and double bonds, was developed by Kekulé. The model for benzene consists of two resonance forms, which corresponds to the double and single bonds superimposing to give rise to six one-and-a-half bonds. Benzene is a more stable molecule than would be expected without accounting for charge delocalization.
Oxazoline is a five-membered heterocyclic organic compound containing one atom of oxygen and nitrogen. It exists between oxazole and oxazolidine in terms of saturation. It was first characterised in 1889 and was named in-line with the Hantzsch–Widman nomenclature. Compounds containing this ring are referred to as oxazolines or oxazolyls and have a variety of chemical uses; particularly as ligands in asymmetric catalysis and as protecting groups for carboxylic acids.
Oxirene is a hypothesized heterocyclic chemical compound which contains an unsaturated three-membered ring containing two carbon atoms and one oxygen atom. As the configuration is extremely strained, no consensus exists whether the structure constitutes a molecule or whether it is merely a transition state. The substance is therefore mainly evaluated by molecular modeling techniques. Experimental indications exist that oxirene occurs in the Wolff rearrangement.
A nitrone is the N-oxide of an imine and a functional group in organic chemistry. The general structure is R1R2C=NR3+O- where R3 is different from H. A nitrone is 1,3-dipole in 1,3-dipolar cycloadditions. It reacts with alkenes to form an isoxazolidine: One example of this reaction type is the reaction of various Baylis-Hillman adducts with C-Phenyl-N-methylnitrone forming an isoxazolidine in which R1 is phenyl, R2 is hydrogen and R3 is a methyl group. Nitrones react with terminal alkynes and a copper salt to beta-lactam. This reaction is also called The Kinugasa reaction for example in this reaction: The first step in this reaction is a dipolar cycloaddition of the nitrone with the in situ generated copper acetylide to a 5-membered ring structure which rearranges in the second step.
Dithiothreitol is the common name for a small-molecule redox reagent known as Cleland's reagent. DTT's formula is C4H10O2S2 and the molecular structure of its reduced form is shown at the right; its oxidized form is a disulfide-bonded 6-membered ring. Its name derives from the four-carbon sugar, threose. DTT has an epimeric compound, dithioerythritol.
Pyridazine is a heteroaromatic organic compound with the molecular formula C4H4N2, sometimes called 1,2-diazine. It contains a six-membered ring with two adjacent nitrogen atoms. It is a colorless liquid with a boiling point of 208 °C. Pyridazine has no household use. It is mainly used in research and industry as building block for more complex compounds. The pyridazine structure is found within a number of herbicides such as credazine, pyridafol and pyridate. It is also found within the structure of several pharmaceutical drugs such as cefozopran, cadralazine, minaprine, pipofezine, hydralazine, and cilazapril.
Ethylene oxide, also called oxirane, is the organic compound with the formula C 2H 4O. It is a cyclic ether. Ethylene oxide is a colorless flammable gas at room temperature, with a faintly sweet odor; it is the simplest epoxide: a three-membered ring consisting of one oxygen atom and two carbon atoms. Because of its special molecular structure, ethylene oxide easily participates in addition reactions; e.g., opening its ring and thus easily polymerizing. Ethylene oxide is isomeric with acetaldehyde. Although it is a vital raw material with diverse applications, including the manufacture of products like polysorbate 20 and polyethylene glycol that are often more effective and less toxic than alternative materials, ethylene oxide itself is a very hazardous substance: at room temperature it is a flammable, carcinogenic, mutagenic, irritating, and anaesthetic gas with a misleadingly pleasant aroma. The chemical reactivity that is responsible for many of ethylene oxide's hazards has also made it a key industrial chemical. Although too dangerous for direct household use and generally unfamiliar to consumers, ethylene oxide is used industrially for making many consumer products as well as non-consumer chemicals and intermediates. Ethylene oxide is important or critical to the production of detergents, thickeners, solvents, plastics, and various organic chemicals such as ethylene glycol, ethanolamines, simple and complex glycols, polyglycol ethers and other compounds. As a poison gas that leaves no residue on items it contacts, pure ethylene oxide is a disinfectant that is widely used in hospitals and the medical equipment industry to replace steam in the sterilization of heat-sensitive tools and equipment, such as disposable plastic syringes.
Quinazoline is a heterocyclic compound made up of two fused six-membered simple aromatic rings, a benzene ring and a pyrimidine ring. Its chemical formula is C8H6N2. Quinazoline is yellow solid. It is isomeric with other naphthyridines including quinoxaline, phthalazine and cinnoline. Derivatives of quinazoline are called quinazolines. Medicinally it has been used in various areas especially as an anti-malarial agent and in cancer treatment. One example of a compound containing the quinazoline structure is doxazosin mesylate. The ring system is typically prepared by heating 2-acylanilides in the presence of ammonia or amines.
Tetrahydropyran is the organic compound consisting of a saturated six-membered ring containing five carbon atoms and one oxygen atom. The compound is a colourless volatile liquid, but is obscure. Derivatives of tetrahydropyran are, however, more common. Tetrahydropyranyl ethers derived from the reaction of alcohols and dihydropyran are common intermediates in organic synthesis. Furthermore, tetrahydropyran ring system, i.e. a five carbon atoms and an oxygen, is the core of pyranose sugars, such as glucose.
Tacrolimus is an immunosuppressive drug that is mainly used after allogeneic organ transplant to reduce the activity of the patient's immune system and so lower the risk of organ rejection. It is also used in a topical preparation in the treatment of atopic dermatitis, severe refractory uveitis after bone marrow transplants, exacerbations of minimal change disease, and the skin condition vitiligo. It is a 23-membered macrolide lactone discovered in 1984 from the fermentation broth of a Japanese soil sample that contained the bacteria Streptomyces tsukubaensis. It reduces interleukin-2 production by T-cells.
Dioxolane is a heterocyclic acetal with the chemical formula (CH2)2O2CH2. It is related to tetrahydrofuran by interchange of one oxygen for a CH2 group. The corresponding saturated 6-membered C4O2 rings are called dioxanes. The isomeric 1,2-dioxolane is a peroxide. 1,3-Dioxolane is used as a solvent and as a comonomer in polyacetals.
Pentazole is an aromatic chemical molecule consisting of a five-membered ring with all nitrogen atoms, one of which is bonded to a hydrogen atom. It has a molecular formula of HN5. Its SMILES structure is n1n[nH]nn1. Although strictly speaking a homocyclic, inorganic compound, pentazole has historically been classed as the last in a series of heterocyclic azole compounds containing one to five nitrogen atoms. This set contains pyrrole, imidazole, pyrazole, triazoles, tetrazoles, and pentazole. One can consider pentazole to be at the interface between inorganic and organic chemistry.
Cyclooctane is a cycloalkane with the molecular formula (CH2)8. It is a simple colourless hydrocarbon, but it is often a reference compound for saturated eight-membered ring compounds in general.
Oxazolidine is a five-membered ring compound consisting of three carbons, a nitrogen, and an oxygen. The oxygen and NH are the 1 and 3 positions, respectively. In oxazolidine derivatives, there is always a carbon between the oxygen and the nitrogen. All of the carbons in oxazolidines are reduced. Some of their derivatives, the oxazolidinediones, are used as anticonvulsants.
Spiramycin is a macrolide antibiotic. It is used to treat toxoplasmosis and various other infections of soft tissues. Although used in Europe, Canada and Mexico, spiramycin is still considered an experimental drug in the United States, but can sometimes be obtained by special permission from the FDA for toxoplasmosis in the first trimester of pregnancy. Spiramycin has been used in Europe since the year 2000 under the trade name "Rovamycine", produced by Rhone-Poulenc Rorer and Famar Lyon, France and Eczacibasi Ilae, Turkey. It also goes under the name Rovamycine in Canada, where it is mostly marketed to dentists for mouth infections. Spiramycin is a 16-membered ring macrolide. It was discovered in 1952 as a product of Streptomyces ambofaciens. As a preparation for oral administration it has been used since 1955, in 1987 also the parenteral form was introduced into practice. The antibacterial action involves inhibition of protein synthesis in the bacterial cell during translocation. Resistance to spiramycin can develop by several mechanisms and its prevalence is to a considerable extent proportional to the frequency of prescription in a given area. The antibacterial spectrum comprises Gram-positive cocci and rods, Gram-negative cocci and also Legionellae, mycoplasmas, chlamydiae, some types of spirochetes, Toxoplasma gondii and Cryptosporidium sp., Enterobacteria, pseudomonads and pathogenic moulds are resistant. Its action is mainly bacteriostatic, on highly sensitive strains it exerts a bactericide action. As compared with erythromycin, it is in vitro weight for weight 5 to 20 less effective, an equipotential therapeutic dose is, however, only double. This difference between the effectiveness in vitro and in vivo is explained above all by the great affinity of spiramycin to tissues where it achieves concentrations many times higher than serum levels. An important part is played also by the slow release of the antibiotic from the tissue compartment, the marked action on microbes in sub-inhibition concentrations and the relatively long persisting post-antibiotic effect. Its great advantage is the exceptionally favourable tolerance-gastrointestinal and general. It is available for parenteral and oral administration
In molecular biology, Morpholino describes a molecule in a particular structural family that is used to modify gene expression. Morpholino oligomers are a kind of antisense, a technology used to block access of other molecules to specific sequences within nucleic acid. Morpholinos block small regions of the base-pairing surfaces of ribonucleic acid. Most Morpholinos are used as research tools for reverse genetics by knocking down gene function. This article discusses only the Morpholino antisense oligos, which are nucleic acid analogs. The word "morpholino" can occur in other chemical names, referring to chemicals containing a six-membered morpholine ring. To help avoid confusion with other morpholine-containing molecules, when describing oligos "Morpholino" is often capitalized as a trade name, though this usage is not consistent throughout the scientific literature. Morpholinos are sometimes referred to as "PMO". Gene knockdown is achieved by preventing cells from making a targeted protein. Morpholinos can also modify the splicing of pre-mRNA. Knocking down gene expression is a powerful method for learning about the function of a particular protein; in similar manner, causing a specific exon to be spliced out of a protein can help to determine the function of the protein moiety encoded by that exon or can sometimes knock down the protein activity altogether. These molecules have been applied to studies in several model organisms, including mice, zebrafish, frogs, and sea urchins.
Fluoranthene is a polycyclic aromatic hydrocarbon consisting of a naphthalene and a benzene unit connected by a five-membered ring. It is a member of the class of PAHs known as non-alternant PAHs because it has rings other than those with six carbon atoms. It is a structural isomer of the alternant PAH pyrene. It is not as thermodynamically stable as pyrene because its electrons cannot resonate throughout the complete structure like the corresponding ones in pyrene. Fluoranthene is found in many combustion products, along with other PAHs. Its presence is an indicator of less efficient or lower-temperature combustion, since non-alternant PAHs are less preferred in formation than alternant PAHs. Fluoranthene is one of the U.S. Environmental Protection Agency's 16 priority pollutant PAHs. Fluoranthene has been classified by the International Agency for Research on Cancer as a group 3 carcinogen, "not classifiable as to its carcinogenicity to humans", however it was found to possess carcinogenic properties in case of newborn mice according to short-term lung tumor assay. Fluoranthene has been isolated from coal tar pitch. Its name is derived from its fluorescence under UV light.
Thiazolidines are a class of heterocyclic organic compounds with a 5-membered saturated ring with a thioether group and an amine group in the 1 and 3 positions, respectively. It is a sulfur analogue of oxazolidine. The drug pioglitazone contains a thiazolidine ring. It is a drug usually indicated in cases of type II diabetes for decreasing blood sugar. It also decreases triglycerides and C-reactive protein levels. It lowers blood pressure and increases levels of HDL. Another drug which contains a thiazolidine ring is the antibiotic drug penicillin. Thiazolidines may be synthesized by a condensation reaction between a thiol and an aldehyde or ketone. The reaction is reversible. Therefore, many thiazolidines are labile towards hydrolysis in aqueous solution. Hydrolysis of the thiazolidine generates the thiol and aldehyde or ketone from which it was synthesized.
The macrolides are a group of drugs whose activity stems from the presence of a macrolide ring, a large macrocyclic lactone ring to which one or more deoxy sugars, usually cladinose and desosamine, may be attached. The lactone rings are usually 14-, 15-, or 16-membered. Macrolides belong to the polyketide class of natural products.
Diazole refers to either one of a pair of isomeric chemical compounds with molecular formula C3H4N2, having a five-membered ring consisting of three carbon atoms and two nitrogen atoms. The two isomers are: ⁕Imidazole ⁕Pyrazole
Lactaldehyde is an intermediate in the methylglyoxal metabolic pathway. Methylglyoxal is converted to D-lactaldehyde by glycerol dehydrogenase. Lactaldehyde is then oxidized to lactic acid by aldehyde dehydrogenase. Lactaldehyde exists in several forms: in open-chain form and as cyclic hemiacetal; in solution and in crystal forms; as monomer and as dimer. In crystal form, three conformers occur as hemiacetal dimers with a 1,4-dioxane ring skeleton. In equilibrium solution, negligibly small amounts of the monomer and at least one five-membered ring dimer exist.
ε-Caprolactone or simply caprolactone is a cyclic ester, a member of the lactone family, with a seven-membered ring with the formula (CH2)5CO2. This colorless liquid is miscible with most organic solvents. It is produced on a very large scale as a precursor to caprolactam.
Thromboxane is a member of the family of lipids known as eicosanoids. The two major thromboxanes are thromboxane A2 and thromboxane B2. The distinguishing feature of thromboxanes is a 6-membered ether-containing ring. Thromboxane is named for its role in clot formation.
Piperazine is an organic compound that consists of a six-membered ring containing two nitrogen atoms at opposite positions in the ring. Piperazine exists as small alkaline deliquescent crystals with a saline taste. The piperazines are a broad class of chemical compounds, many with important pharmacological properties, which contain a core piperazine functional group.
Aminoshikimic acid is a synthetic crystalline carboxylic acid. It is characterized by multiple stereogenic centers and functional groups arrayed around a six-membered carbocyclic ring. Aminoshikimic acid is also an alternative to shikimic acid as a starting material for the synthesis of neuraminidase inhibitors such as the antiinfluenza agent oseltamivir.
Benzothiazine is a heterocyclic compound consisting of a benzene ring attached to the 6-membered heterocycle thiazine. The name is applied to both the 2H- and 4H- isomers of the molecule. 2,1-Benzothiazine, a type of benzothiazines was first reported in the 1960s. Subsequently, their preparation and intensive biological and physiological studies have been reported. In recent years, 2,1-benzothiazines have been of enormous interest to synthetic chemists. An enantioselective synthesis of such benzothiazines has been developed by Harmata and Hong who have formulated transformations of these compounds designed to target chiral, non-racemic building blocks as well as natural products.
An isothiazole, or 1,2-thiazole, is a type of organic compound containing a five-membered aromatic ring that consists of three carbon atoms, one nitrogen atom, and one sulfur atom. Isothiazole is a member of a class of compounds known as azoles. In contrast to the isomeric thiazole, the two heteroatoms are in adjacent positions. The ring structure of isothiazole is incorporated into larger compounds with biological activity such as the pharmaceutical drugs ziprasidone and perospirone.
A β-lactam ring, is a four-membered lactam. It is named as such, because the nitrogen atom is attached to the β-carbon relative to the carbonyl. The simplest β-lactam possible is 2-azetidinone.
Tetrahydrothiophene is an organosulfur compound with the formula (CH2)4S. It consists of a five-membered ring containing four carbon atoms and a sulfur atom. It is the saturated analog of thiophene. It is a volatile, colorless liquid with an intensely unpleasant odor. It is also known as thiophane or THT.
Lactide is the cyclic di-ester of lactic acid, i.e., 2-hydroxypropionic acid. Lactic acid cannot form a lactone as other hydroxy acids do because the hydroxy group is too close to the carboxylic group. Instead, lactic acid first forms a dimer, which is similar to a 5-hydroxyacid. The dimer contains a hydroxy group at a convenient distance from the carboxylic group for the formation of a lactone. Indeed, the dimer readily forms a six-membered cyclic diester known as lactide. Lactides may be prepared by heating lactic acid in the presence of an acid catalyst. In general, a lactide is the cyclic diester, i.e., the di-lactone of two molecules of any 2-hydroxycarboxylic acid.
Azithromycin is an azalide, a subclass of macrolide antibiotics. Azithromycin is one of the world's best-selling antibiotics. It is derived from erythromycin, with a methyl-substituted nitrogen atom incorporated into the lactone ring, thus making the lactone ring 15-membered. Azithromycin is used to treat or prevent certain bacterial infections, most often those causing middle ear infections, strep throat, pneumonia, typhoid, bronchitis and sinusitis. In recent years, it has been used primarily to prevent bacterial infections in infants and those with weaker immune systems. It is also effective against certain sexually transmitted infections, such as nongonococcal urethritis, chlamydia, and cervicitis. Recent studies have indicated it also to be effective against late-onset asthma, but these findings are controversial and not widely accepted.
Pyrrole is a heterocyclic aromatic organic compound, a five-membered ring with the formula C4H4NH. It is a colourless volatile liquid that darkens readily upon exposure to air. Substituted derivatives are also called pyrroles, e.g., N-methylpyrrole, C4H4NCH3. Porphobilinogen, a trisubstituted pyrrole, is the biosynthetic precursor to many natural products such as heme. Pyrroles are components of more complex macrocycles, including the porphyrins of heme, the chlorins, bacteriochlorins, chlorophyll, porphyrinogens.
Oxepin is an oxygen-containing heterocycle consisting of a seven-membered ring with three double bonds. It exists as an equilibrium mixture with benzene oxide. The oxepin-benzene oxide system has fluctuating bonds in which the equilibrium can be shifted to one extreme or the other by suitable substituents. This compound is not aromatic.
Ovalene is a polycyclic aromatic hydrocarbon with the formula C32H14, which consists of ten peri-fused six-membered rings. It is very similar to coronene. Ovalene is a reddish-orange compound. It is sparingly soluble in solvents such as benzene, toluene, and dichloromethane. Its solutions have a green fluorescence under UV light. Ovalene has been shown to form in deep-sea hydrothermal vent areas and in the hydrocracking process of petroleum refining.
Aziridines are organic compounds containing the aziridine functional group, a three-membered heterocycle with one amine group and two methylene bridges. The parent compound is aziridine, with molecular formula C2H5N.
Pyrazolone, a five-membered-ring lactam, is a derivative of pyrazole that has an additional keto group. It has a molecular formula of C3H4N2O. There are two possible isomers: 3-pyrazolone and 5-pyrazolone. Examples of derivatives include: ⁕Ampyrone ⁕Metamizole ⁕Phenazone
Azirines are three membered heterocyclic unsaturated compounds containing a nitrogen atom and related to the saturated analogue aziridine. They are highly reactive yet have reported in a few natural products such as Dysidazirine. There are two isomers of azirine: 1H-azirines with a carbon-carbon double bond are not stable and rearrange to the tautomeric 2H-azirine, a compound with a carbon-nitrogen double bond. 2H-Azirines can be considered strained imines and are isolable.
Penams are a subclass of the broader β-lactam family of antibiotics and related compounds. Penams contain a β-lactam ring fused to a 5-membered ring, where one of the atoms in the ring is a sulfur and the ring is fully saturated. Penicillin is a member of this family of compounds.
Trioxane refers to any of three isomeric organic compounds composed of a six membered ring with three carbon atoms and three oxygen atoms, having the molecular formula C3H6O3. The three isomers are ⁕1,2,3-Trioxane, a hypothetical compound related to molozonide ⁕1,2,4-Trioxane, a hypothetical compound whose skeleton occurs as a structural element of some antimalarial agents. ⁕1,3,5-Trioxane, a trimer of formaldehyde used as fuel and in plastics manufacture.
Piperidine is an organic compound with the molecular formula (CH2)5NH. This heterocyclic amine consists of a six-membered ring containing five methylene bridges and one amine bridge. It is a colorless fuming liquid with an odor described as ammoniacal, pepper-like; the name comes from the genus name Piper, which is the Latin word for pepper. Piperidine is a widely used building block and chemical reagent in the synthesis of organic compounds, including pharmaceuticals.
Cycloheptene is a 7-membered cycloalkene with a flash point of -6.7 °C. It is a raw material in organic chemistry and a monomer in polymer synthesis. Cycloheptene can exist as either the cis- or the trans-isomer.
Mesoionic chemical compounds are dipolar five- or six- membered heterocyclic compounds in which both the negative and the positive charges are delocalized. A completely uncharged structure cannot be written and mesoionic compounds cannot be represented satisfactorily by any one mesomeric structure. The formal positive charge is associated with the ring atoms and the formal negative charge is associated either with ring atoms or an exocyclic nitrogen atom. Mesoionic compounds are a subclass of betaines. Examples are sydnones and sydnone imines, and münchnones.
Pyranose is a collective term for carbohydrates that have a chemical structure that includes a six-membered ring consisting of five carbon atoms and one oxygen atom. The name derives from its similarity to the oxygen heterocycle pyran, but the pyranose ring does not have double bonds. A pyranose in which the anomeric OH at C has been converted into an OR group is called a pyranoside.
Thietane is a heterocyclic compound containing a saturated four-membered ring with three carbon atoms and one sulfur atom.
Azete is a heterocyclic chemical compound consisting of an unsaturated four-membered ring with three carbon atoms and one nitrogen atom.
Cyclooctene is a cycloalkene with an eight-membered ring. It is notable because it is the smallest cycloalkene that can exist as either the cis- or trans-isomer with the cis-isomer more common. Its most stable cis stereoisomer can adopt various conformations, the most stable one being shaped like a ribbon; its most stable trans-conformer is shaped like the 8-carbon equivalent chair conformation of cyclohexane.
The avermectins are a series 16-membered macrocyclic lactone derivatives with potent anthelmintic and insecticidal properties. These naturally occurring compounds are generated as fermentation products by Streptomyces avermitilis, a soil actinomycete. Eight different avermectins were isolated in 4 pairs of homologue compounds, with a major and minor component usually in ratios of 80:20 to 90:10. Other anthelmintics derived from the avermectins include ivermectin, selamectin, doramectin and abamectin.
Iridoids are a class of secondary metabolites found in a wide variety of plants and in some animals. They are monoterpenes biosynthesized from isoprene and they are often intermediates in the biosynthesis of alkaloids. Chemically, the iridoids usually consist of a cyclopentane ring fused to a six-membered oxygen heterocycle. The chemical structure is exemplified by iridomyrmecin, a defensive chemical produced by the Iridomyrmex genus, for which iridoids are named. Cleavage of a bond in the cyclopentane ring gives rise to a subclass known as seco-iridoids, such as amarogentin. Iridoids are typically found in plants as glycosides, most often bound to glucose.
A polyquinane and polyquinene is a saturated or unsaturated, respectively, polycyclic hydrocarbon consisting of fused five-membered rings. The simplest member is the bicyclic compound bicyclo[3.3.0]octane. Other members are triquinacene and dodecahedrane.
Enediynes are a class of bacterial natural products characterized by either nine- and ten-membered rings containing two triple bonds separated by a double bond. Many of these compounds are capable of undergoing Bergman cyclization. The resulting diradical, a 1,4-dehydrobenzene derivative, is capable of abstracting hydrogen atoms from the sugar backbone of DNA which results in strand scission. This high reactivity with DNA makes the substances toxic. They are being researched as antitumor agents. Several of the naturally occurring enediynes have entered clinical trials against cancer and in Japan neocarzinostatin is used clinically. Three classes of enediynes exist: ⁕Calicheamicin/esperamicin ⁕Dynemicin ⁕Chromoprotein types The enediyne group in those compounds is often called a warhead.
Azetidine is a heterocyclic organic compound. It belongs to the class of four membered rings and it contains a nitrogen atom.
β-Propiolactone is an organic compound of the lactone family, with a four-membered ring. It is a clear, colorless liquid with a slightly sweet odor, highly soluble in water and miscible with ethanol, acetone, diethyl ether and chloroform. The word propiolactone usually refers to this compound, although it may also refer to α-propiolactone. β-Propiolactone is "reasonably expected to be a human carcinogen". It was once widely used in the manufacture of acrylic acid and its esters, but its use has been mostly phased out in favor of safer and less expensive alternatives. β-Propiolactone is a disinfectant and has been used to sterilize blood plasma, vaccines, tissue grafts, surgical instruments, and enzymes. The principal current use of propiolactone is an intermediate in the synthesis of other chemical compounds. β-Propiolactone will slowly react with water and hydrolyse to produce 3-hydroxypropionic acid.
Thiophene, also commonly called thiofuran, is a heterocyclic compound with the formula C4H4S. Consisting of a flat five-membered ring, it is aromatic as indicated by its extensive substitution reactions. Related to thiophene are benzothiophene and dibenzothiophene, containing the thiophene ring fused with one and two benzene rings, respectively. Compounds analogous to thiophene include furan and pyrrole.
Streptogramin A is group of antibiotics within the larger family of antibiotics known as streptogramins. They are synthesized by the bacteria Streptomyces virginiae. The streptogramin family of antibiotics consists of two distinct groups: group A antibiotics contain a 23-membered unsaturated ring with lactone and peptide bonds while group B antibiotics are depsipeptides. While structurally different, these two groups of antibiotics act synergistically, providing greater antibiotic activity than the combined activity of the separate components. These antibiotics have until recently been commercially manufactured as feed additives in agriculture, although today there is increased interest in their ability to combat antibiotic-resistant bacteria, particularly vancomycin-resistant bacteria.
A dioxirane is a molecule containing a three-membered ring composed of one carbon and two oxygens. Somewhat unstable, they are used in organic synthesis as oxidizing reagents. A dioxirane in common use is dimethyldioxirane, the dioxirane derived from acetone.
In chemistry, a ladderane is an organic molecule containing two or more fused cyclobutane rings. The name arises from the resemblance of a series of fused cyclobutane rings to a ladder. Numerous synthetic approaches have been developed for the synthesis of ladderane compounds of various lengths. The mechanisms often involve [2 + 2] photocycloadditions, a useful reaction for creating strained 4-membered rings. Naturally occurring ladderanes have been identified as major components of the anammoxosome membrane of the anammox bacteria, Planctomycetes.
Cyclopentanone is an organic compound with the formula (CH2)4CO. It is a colorless liquid with a peppermint-like odor. It is a cyclic ketone, structurally similar to cyclopentane, consisting of a five-membered ring containing a ketone functional group.
Roxithromycin is a semi-synthetic macrolide antibiotic. It is used to treat respiratory tract, urinary and soft tissue infections. Roxithromycin is derived from erythromycin, containing the same 14-membered lactone ring. However, an N-oxime side chain is attached to the lactone ring. It is also currently undergoing clinical trials for the treatment of male-pattern hair loss. Roxithromycin is available under several brandnames, for example, Xthrocin, Roxl-150, Roxo, Surlid, Rulide, Biaxsig, Roxar, Roximycin, Roxomycin, Rulid, Tirabicin and Coroxin. Roxithromycin is not available in the United States. Roxithromycin has also been tested to possess antimalarial activity.
Phosphole is the organic compound with the chemical formula C4H4PH; it is the phosphorus analog of pyrrole. The term phosphole also refers to substituted derivatives of the parent heterocycle. These compounds are of theoretical interest but also serve as ligands for transition metals and as precursors to more complex organophosphorus compounds. The first phosphole, pentaphenylphosphole, was reported in 1953, and the parent phosphole itself was first described in 1987. The usual route to phospholes is via the McCormack reaction, involving the addition of a 1,3-diene to a phosphonous chloride followed by dehydrohalogenation. Phenylphospholes can be prepared via zirconacyclopentadienes by reaction with PhPCl2. Unlike the related 5-membered heterocycles pyrrole, thiophene, and furan, the aromaticity of phospholes is diminished, reflecting the reluctance of phosphorus to delocalize its lone pair. For example, phospholes undergo Diels-Alder reactions with electrophilic alkynes.
Azocane is a heterocyclic organic compound with the molecular formula C7H15N. It consists of a saturated eight-membered ring having seven carbon atoms and one nitrogen atom attached to a single hydrogen atom. The fully unsaturated analog of azocane is azocine.
Furan is a heterocyclic organic compound, consisting of a five-membered aromatic ring with four carbon atoms and one oxygen. The class of compounds containing such rings are also referred to as furans. Furan is a colorless, flammable, highly volatile liquid with a boiling point close to room temperature. It is soluble in common organic solvents, including alcohol, ether and acetone, but is slightly soluble in water. It is toxic and may be carcinogenic. Furan is used as a starting point to other specialty chemicals.
The chemical substance 1,2-dioxetane is an heterocyclic organic compound with formula C2O2H4, containing a ring of two adjacent oxygen atoms and two adjacent carbon atoms. It is therefore an organic peroxide, and can be viewed as a dimer of formaldehyde. In the 1960s, biochemists discovered that some derivatives of 1,2-dioxetane have a fleeting existence as intermediates in the reactions responsible for the bioluminescence in fireflies, glow-worms and other luminescent creatures. The hypothesis could not be proved because these four-membered cyclic peroxides are quite unstable. Then in 1968 the first example of a stable dioxetane derivative was made at the University of Alberta in Edmonton: 3,3,4-trimethyl-1,2-dioxetane, prepared as a yellow solution in benzene. When heated to 333 K, it decomposed smoothly to acetone and acetaldehyde with the emission of pale blue light. The second example of a dioxetane derivative was made shortly after: the symmetrical compound 3,3,4,4-tetramethyl-1,2-dioxetane, obtained as pale yellow crystals that sublimed even when kept in the refrigerator. Benzene solutions of this compound also decomposed smoothly with the emission of blue light. By adding compounds that normally fluoresce in UV light the colour of the emitted light could be altered.
Diazepine is a seven-membered heterocyclic compound with two nitrogen atoms. Types include: ⁕1,2-diazepine ⁕1,3-diazepine ⁕1,4-diazepine When combined with a benzene ring, it is the basis of the benzodiazepine family of compounds. In these compounds the nitrogen atoms are at the 1 and 5 positions as, for example, in clobazam.
Pyrazole is the organic compound with the formula C3H3N2H. It is a heterocycle characterized by a 5-membered ring of three carbon atoms and two adjacent nitrogen centres. Pyrazoles are also the class of compounds that have the ring C3N2 with adjacent nitrogen centres. Notable drug that is a pyrazole is Celebrex.
Limonoids are phytochemicals, abundant in citrus fruit and other plants of the families Rutaceae and Meliaceae. Currently limonoids are under investigation for a wide variety of therapeutic effects such as antiviral or Viricide, antifungal, antibacterial, antineoplastic and antimalarial. Certain limonoids are insecticides such as azadirachtin from the neem tree. Chemically, the limonoids consist of variations of the furanolactone core structure. The prototypical structure consists of 4 six-membered rings and a furan ring. Limonoids are classed as tetranortriterpenes. Citrus fruits contain the limonoids limonin, nomilin and nomilinic acid, while both neem seeds and leaves contain the limonoid azadirachtin, although higher concentrations are present in the former.
Cupferron, the ammonium salt of N-nitroso-N-phenylhydroxylamine, is a common reagent for the complexation of metal ions. Its formula is NH4[C6H5NNO]. The anion binds to metal cations through the two oxygen atoms, forming five-membered chelate rings. Cupferron is prepared from phenylhydroxylamine and an NO+ source:
In organic chemistry, sultones are cyclic sulfonate esters of hydroxy sulfonic acids that exist mainly as four-, seven-, and sometimes five-membered rings. They are often short-lived intermediates, used as strong alkylating agents to introduce a negatively charged sulfonate group. In the presence of water, they slowly hydrolyze to their respective corrosive hydroxy sulfonic acids. Sultones decompose when heated to produce toxic, foul smelling, sulfur dioxide fumes. Sultone oximes are key intermediates in the synthesis of the anti-convulsant drug zonisamide. Sultones are classified as toxic, carcinogenic, mutagenic, and teratogenic.
A furanose is a collective term for carbohydrates that have a chemical structure that includes a five-membered ring system consisting of four carbon atoms and one oxygen atom. The name derives from its similarity to the oxygen heterocycle furan, but the furanose ring does not have double bonds.
Azepane is a saturated heterocycle, containing one nitrogen atom in seven-membered ring. A well known azepane derivative is caprolactam.
The rotanes are a class of hydrocarbon consisting of spiro-linked cyclopropane units having a common n-membered ring in the middle. They are named [n]rotanes depending on the number of carbon atoms in the middle ring. The simplest of them, rotane, is a branched triangulane.
Seven membered heterocyclic rings containing a NITROGEN atom.
— U.S. National Library of Medicine