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Preferred IUPAC name Disodium (12S,14aR,15aS,16aR,17aS,18Z,110aR,111aS,112aR,113aS,114aR,116R,117R,118aS,119aR,121aS,122aR,123aS,124aR,125aS,126aR,127aS,22S,24aR,25aS,26aR,27aS,28aR,29aS,211R,212R,213aR,214S,214aS,215aR,217aS,218aR,219aS,32R,33R,34aS,36S,37R,38R,38aS,5R,7R,82S,83R,84aS,86R,87R,88R,88aS,92R,93R,94R,94aS,95aS,96aR,97aS,98R,99R,910S,911aR,912aS,913aR,914R,914aR,11S,12R,132S,133R,134S,134aS,135aR,136aS,137aR,138S,138aS,1310S,1311R,1312aR,1313aS,1314aR,1315aS,1317R,1317aR)-12-[(1S,2R,4R,5S)-1,2-dihydroxy-4,5-dimethyloct-7-en-1-yl]-117,211,214,33,37,38,5,7,83,87,88,93,94,98,914,11,12,133,134,138,1311,1317-docosahydroxy-14a,15a,16a,114a,116,119a,121a,122a,25a,27a,29a,214a,217a,1313a,1315a-pentadecamethyl-132-[(2R,3R,4R,7S,8R,9R,11R,13E)-3,8,11,15-tetrahydroxy-4,9,13-trimethyl-12-methylidene-7-(sulfonatooxy)pentadec-13-en-2-yl]-13,14,14a,15a,16,16a,17a,110,110a,111a,112,112a,113a,114,114a,116,117,118,118a,119a,120,121,121a,122a,123,123a,124a,125,125a,126a,127,127a,22,23,24,24a,25a,26,26a,27a,28,28a,29a,210,211,212,213a,214,214a,215a,216,217,217a,218a,219,219a,32,33,34,34a,36,37,38,38a,82,83,84,84a,86,87,88,88a,93,94,94a,95a,96,96a,97a,98,99,910,911a,912,912a,913a,914,914a,133,134,134a,135a,136,136a,137a,138,138a,1310,1311,1312,1312a,1313a,1314,1314a,1315a,1316,1317,1317a-octahectahydro-12H,92H,132H-1(16)-pyrano[2′′′ ′,3′′′ ′:5′′′,6′′′]pyrano[2′′′,3′′′:6′′,7′′]oxepino[2′′,3′′:5′,6′]pyrano[2′,3′:5,6]pyrano[3,2-b]pyrano[2′′′,3′′′:5′′,6′′]pyrano[2′′,3′′:5′,6′]pyrano[2′,3′:5,6]pyrano[2,3-g]oxocina-2(2,12)-bis(pyrano[2′′,3′′:5,6]pyrano[2′,3′:5,6]pyrano)[3,2-b:2′,3′-f]oxepina-13(10)-pyrano[3,2-b]pyrano[2′′′,3′′′:5′′,6′′]pyrano[2′′,3′′:5′,6′]pyrano[2′,3′:5,6]pyrano[2,3-f]oxepina-9(2,10)-dipyrano[2,3-e:2′,3′-e′]pyrano[3,2-b:5,6-b′]dipyrana-3,8(2,6)-bis(pyrano[3,2-b]pyrana)tridecaphan-99-yl sulfate | |
Identifiers | |
3D model (JSmol) | |
ChEMBL | |
ChemSpider | |
ECHA InfoCard | 100.227.039 |
KEGG | |
PubChem CID | |
UNII | |
CompTox Dashboard (EPA) | |
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Properties | |
C164H256O68S2Na2 | |
Molar mass | 3422 g/mol |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Maitotoxin (MTX) is an extremely potent biotoxin produced by Gambierdiscus toxicus , a dinoflagellate species. Maitotoxin has been shown to be more than one hundred thousand times as potent as VX nerve agent. [1] Maitotoxin is so potent that it has been demonstrated that an intraperitoneal injection of 130 ng/kg was lethal in mice. [2] Maitotoxin was named from the ciguateric fish Ctenochaetus striatus —called "maito" in Tahiti —from which maitotoxin was isolated for the first time. It was later shown that maitotoxin is actually produced by the dinoflagellate Gambierdiscus toxicus.
Maitotoxin activates extracellular calcium channels, leading to an increase in levels of cytosolic Ca2+ ions. [3] The exact molecular target of maitotoxin is unknown, but it has been suggested that maitotoxin binds to the plasma membrane Ca2+ ATPase (PMCA) and turns it into an ion channel, similar to how palytoxin turns the Na+/K+-ATPase into an ion channel. [4] Ultimately, a necroptosis cascade is activated, resulting in membrane blebbing and eventually cell lysis. [5] Maitotoxin can indirectly activate calcium-binding proteases calpain-1 and calpain-2, contributing to necrosis. [6] The toxicity of maitotoxin in mice is the highest for nonprotein toxins: the LD50 is 50 ng/kg. [7]
The molecule itself is a system of 32 fused rings. It resembles large fatty acid chains and it is notable because it is one of the largest and most complex non-protein, non-polysaccharide molecules produced by any organism. Maitotoxin includes 32 ether rings, 22 methyl groups, 28 hydroxyl groups, and 2 sulfuric acid esters and has an amphipathic structure. [8] [9] [10] Its structure was established through analysis using nuclear magnetic resonance at Tohoku University, Harvard University and the University of Tokyo in combination with mass spectrometry, and synthetic chemical methods. However, Andrew Gallimore and Jonathan Spencer have questioned the structure of maitotoxin at a single ring-junction (the J–K junction), based purely on biosynthetic considerations and their general model for marine polyether biogenesis. [11] K. C. Nicolaou and Michael Frederick argue that despite this biosynthetic argument, the originally proposed structure could still be correct. [12] The controversy has yet[ needs update ] to be resolved.
The molecule is produced in nature via a polyketide synthase pathway. [11]
Since 1996 the Nicolaou research group is involved in an effort to synthesise the molecule via total synthesis [13] [14] [15] [16] although as of 2015 the project is on hold due to lack of funding. [17]
Fulminic acid is an acid with the formula HCNO, more specifically H−C≡N+−O−. It is an isomer of isocyanic acid and of its elusive tautomer, cyanic acid, and also of isofulminic acid.
In chemical synthesis, click chemistry is a class of simple, atom-economy reactions commonly used for joining two molecular entities of choice. Click chemistry is not a single specific reaction, but describes a way of generating products that follow examples in nature, which also generates substances by joining small modular units. In many applications, click reactions join a biomolecule and a reporter molecule. Click chemistry is not limited to biological conditions: the concept of a "click" reaction has been used in chemoproteomic, pharmacological, biomimetic and molecular machinery applications. However, they have been made notably useful in the detection, localization and qualification of biomolecules.
Ring-closing metathesis (RCM) is a widely used variation of olefin metathesis in organic chemistry for the synthesis of various unsaturated rings via the intramolecular metathesis of two terminal alkenes, which forms the cycloalkene as the E- or Z- isomers and volatile ethylene.
In organic chemistry, Bredt's rule is an empirical observation that states that a double bond cannot be placed at the bridgehead of a bridged ring system, unless the rings are large enough. The rule is named after Julius Bredt, who first discussed it in 1902 and codified it in 1924. It primarily relates to bridgeheads with carbon-carbon and carbon-nitrogen double bonds.
In organic chemistry, a cycloalkyne is the cyclic analog of an alkyne. A cycloalkyne consists of a closed ring of carbon atoms containing one or more triple bonds. Cycloalkynes have a general formula CnH2n−4. Because of the linear nature of the C−C≡C−C alkyne unit, cycloalkynes can be highly strained and can only exist when the number of carbon atoms in the ring is great enough to provide the flexibility necessary to accommodate this geometry. Large alkyne-containing carbocycles may be virtually unstrained, while the smallest constituents of this class of molecules may experience so much strain that they have yet to be observed experimentally. Cyclooctyne is the smallest cycloalkyne capable of being isolated and stored as a stable compound. Despite this, smaller cycloalkynes can be produced and trapped through reactions with other organic molecules or through complexation to transition metals.
Homoaromaticity, in organic chemistry, refers to a special case of aromaticity in which conjugation is interrupted by a single sp3 hybridized carbon atom. Although this sp3 center disrupts the continuous overlap of p-orbitals, traditionally thought to be a requirement for aromaticity, considerable thermodynamic stability and many of the spectroscopic, magnetic, and chemical properties associated with aromatic compounds are still observed for such compounds. This formal discontinuity is apparently bridged by p-orbital overlap, maintaining a contiguous cycle of π electrons that is responsible for this preserved chemical stability.
A circulene is a macrocyclic arene in which a central polygon is surrounded and fused by benzenoids. Nomenclature within this class of molecules is based on the number of benzene rings surrounding the core, which is equivalent to the size of the central polygon. Examples which have been synthesized include [5]circulene (corannulene), [6]circulene (coronene), [7]circulene, and [12]circulene (kekulene) These compounds belong to a larger class of geodesic polyarenes. Whereas [5]circulene is bowl-shaped and [6]circulene is planar, [7]circulene has a unique saddle-shaped structure. The helicenes are a conceptually related class of structures in which the array of benzene rings form an open helix rather than a closed ring.
Epothilones are a class of potential cancer drugs. Like taxanes, they prevent cancer cells from dividing by interfering with tubulin, but in early trials, epothilones have better efficacy and milder adverse effects than taxanes.
In organic chemistry, propellane is any member of a class of polycyclic hydrocarbons, whose carbon skeleton consists of three rings of carbon atoms sharing a common carbon–carbon covalent bond. The concept was introduced in 1966 by D. Ginsburg Propellanes with small cycles are highly strained and unstable, and are easily turned into polymers with interesting structures, such as staffanes. Partly for these reasons, they have been the object of much research.
In organic chemistry, the acenes or polyacenes are a class of organic compounds and polycyclic aromatic hydrocarbons made up of benzene rings which have been linearly fused. They follow the general molecular formula C4n+2H2n+4.
[n]Radialenes are alicyclic organic compounds containing n cross-conjugated exocyclic double bonds. The double bonds are commonly alkene groups but those with a carbonyl (C=O) group are also called radialenes. For some members the unsubstituted parent radialenes are elusive but many substituted derivatives are known.
Spirotryprostatin B is an indolic alkaloid found in the Aspergillus fumigatus fungus that belongs to a class of naturally occurring 2,5-diketopiperazines. Spirotryprostatin B and several other indolic alkaloids have been found to have anti-mitotic properties, and as such they have become of great interest as anti-cancer drugs. Because of this, the total syntheses of these compounds is a major pursuit of organic chemists, and a number of different syntheses have been published in the chemical literature.
Gambierdiscus toxicus is a species of photosynthetic unicellular eukaryote belonging to the Alveolata, part of the SAR supergroup. It is a dinoflagellate which can cause the foodborne illness ciguatera, and is known to produce several natural polyethers including ciguatoxin, maitotoxin, gambieric acid, and gambierol. The species was discovered attached to the surface of brown macroalgae.
In chemistry, the double bond rule states that elements with a principal quantum number (n) greater than 2 for their valence electrons (period 3 elements and higher) tend not to form multiple bonds (e.g. double bonds and triple bonds). The double bonds, when they exist, are often weak due to poor orbital overlap between the n>2 orbitals of the two atoms. Although such compounds are not intrinsically unstable, they instead tend to polymerize. An example is the rapid polymerization that occurs upon condensation of disulfur, the heavy analogue of O2. Numerous violations to the rule exist.
3-Oxetanone, also called oxetan-3-one or 1,3-epoxy-2-propanone, is a chemical compound with formula C3H4O2. It is the ketone of oxetane, and an isomer of β-propiolactone.
Nucleic acid templated chemistry (NATC), or DNA-templated chemistry, is a tool used in the controlled synthesis of chemical compounds. The main advantage of NAT-chemistry (NATC) is that it allows the user to perform the chemical reaction as an intramolecular reaction. Two oligonucleotides. or their analogues, are linked via chemical groups to precursors of chemical compounds. The oligonucleotides recognize specific nucleic acids and are hybridized sterically close to each other. Afterwards, the chemical active groups interact with each other to combine the precursors into a completely new chemical compound. NATC is usually used to perform synthesis of complex compounds without the need to protect chemically active groups during the synthesis.
Photoactivatable probes, or caged probes, are cellular players that can be triggered by a flash of light. They are used in biological research to study processes in cells. The basic principle is to bring a photoactivatable agent to cells, tissues or even living animals and specifically control its activity by illumination.
Atrop-abyssomicin C is a polycyclic polyketide-type natural product that is the atropisomer of abyssomicin C. It is a spirotetronate that belongs to the class of tetronate antibiotics, which includes compounds such as tetronomycin, agglomerin, and chlorothricin. In 2006, the Nicolaou group discovered atrop-abyssomicin C while working on the total synthesis of abyssomicin C. Then in 2007, Süssmuth and co-workers isolated atrop-abyssomicin C from Verrucosispora maris AB-18-032, a marine actinomycete found in sediment of the Japanese sea. They found that atrop-abyssomicin C was the major metabolite produced by this strain, while abyssomicin C was a minor product. The molecule displays antibacterial activity by inhibiting the enzyme PabB, thereby depleting the biosynthesis of p-aminobenzoate.
The microviridins are a class of serine protease inhibitors produced by various genera of cyanobacteria. Recent genome mining has shown that the biosynthetic gene cluster responsible for microviridin biosynthesis is much more prevalent, found in many species of Pseudomonadota and Bacteriodota.
Gambierol is a marine polycyclic ether toxin which is produced by the dinoflagellate Gambierdiscus toxicus. Gambierol is collected from the sea at the Rangiroa Peninsula in French Polynesia. The toxins are accumulated in fish through the food chain and can therefore cause human intoxication. The symptoms of the toxicity resemble those of ciguatoxins, which are extremely potent neurotoxins that bind to voltage-sensitive sodium channels and alter their function. These ciguatoxins cause ciguatera fish poisoning. Because of the resemblance, there is a possibility that gambierol is also responsible for ciguatera fish poisoning. Because the natural source of gambierol is limited, biological studies are hampered. Therefore, chemical synthesis is required.
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