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1,2-dithiolane
1,2-Dithiolane is an organosulfur compound with the formula . It is also classified as a heterocycle derived from cyclopentane by replacing two methylene bridges ( units) with a disulfide group. 1,3-Dithiolane is an isomer. The parent molecule is unimportant but substituted derivatives, especially lipoic acid and its derivatives, are often essential for life. Several occur naturally. The parent 1,2-dithiolane is the disulfide derived from 1,3-propanedithiol. It is however unstable with respect to oligomerization. In general, 1,3-dithiols are superior reductants relative to monothiols. Natural occurrence Many substituted 1,2-dithiolates are found in nature. The most common is lipoic acid, a chiral dithiolane, which features a pentanoic acid substituent. It is essential for aerobic metabolism in mammals. Some 1,2-dithiolane are found in some foods, such as asparagusic acid in asparagus. The 4-dimethylamino derivative nereistoxin was the inspiration for insecticides that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nereistoxin
Nereistoxin is a natural product identified in 1962 as the toxic organic compound ''N'',''N''-dimethyl-1,2-dithiolan-4-amine. It had first been isolated in 1934 from the marine annelid ''Lumbriconereis heteropoda'' and acts by blocking the nicotinic acetylcholine receptor. Researchers at Takeda Pharmaceutical Company, Takeda in Japan investigated it as a possible insecticide. They subsequently developed a number of derivatives that were commercialised, including those with the International Organization for Standardization, ISO trivial name, common names bensultap, cartap, thiocyclam and thiosultap. Structures and synthesis Cartap.svg, Cartap Bensultap.svg, Bensultap Thiosultap.svg, Thiosultap Thiocyclam neutral.svg, Thiocyclam Bensultap (R=SO2Ph) was made by the reaction of the sodium salt of benzenethiolsulfonate (PhSO2SNa) with ''N'',''N''-dimethyl 1,3-dichloro-2-propylamine or ''N'',''N''-dimethyl 2,3-dichloropropylamine in ethanol. : Bensultap can be converted to nereistoxin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asparagusic Acid
Asparagusic acid is an organosulfur compound with the molecular formula C4H6O2S2 and systematically named 1,2-dithiolane-4-carboxylic acid. The molecule consists of a heterocyclic disulfide functional group (a 1,2- dithiolane) with a carboxylic acid side chain. It is found in asparagus and is believed to be the metabolic precursor to odorous sulfur compounds responsible for the distinctive smell of urine which has long been associated with eating asparagus. Isolation and biosynthesis The material was originally isolated from an aqueous extract of '' Asparagus officinalis'', a spring vegetable. It is a derivative of the cyclic disulfide organic compound 1,2-dithiolane with a carboxylic acid functional group bound to carbon-4 of the heterocycle. Biosynthetic studies revealed that asparagusic acid is derived from isobutyric acid. Asparagusic acid is a colorless solid with a melting point of 75.7–76.5 °C, higher than that of the corresponding dithiol: dihydroaspar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disulfide
In chemistry, a disulfide (or disulphide in British English) is a compound containing a functional group or the anion. The linkage is also called an SS-bond or sometimes a disulfide bridge and usually derived from two thiol groups. In inorganic chemistry, the anion appears in a few rare minerals, but the functional group has tremendous importance in biochemistry. Disulfide bridges formed between thiol groups in two cysteine residues are an important component of the tertiary and quaternary structure of proteins. Compounds of the form are usually called ''persulfides'' instead. Organic disulfides Structure Disulfides have a C–S–S–C dihedral angle approaching 90°. The S–S bond length is 2.03 Å in diphenyl disulfide, similar to that in elemental sulfur. Disulfides are usually symmetric but they can also be unsymmetric. Symmetrical disulfides are compounds of the formula . Most disulfides encountered in organosulfur chemistry are symmetrical disulfides. Unsymme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1,3-Dithiolane
1,3-Dithiolane is the organosulfur compound with the formula . Also classified as a heterocycle related cyclopentane by replacing two methylene bridges ( units) with thioether groups. It is an isomer of 1,2-dithiolane. 1,3-Dithiolanes are compounds where one or more H atoms of the parent 1,3-dithiolane are replaced by other groups. These species are more widely studied. Synthesis A common family of 1,3-dithiolanes have the formula . They are obtained by treating an aldehyde with 1,2-ethanedithiol. Related compounds with the formula are obtained by condensation of 1,2-ethanedithiol with ketones. The dithiolane protected aldehydes and ketones are amenable to many reactions without perturbing the dithiolane ring. Dithiolanes can often be reverted, i.e., deprotected, to the parent aldehyde and ketone. A variety of reagents have been developed for that purpose. Reactions 1,3-Dithiolanes derived from aldehydes can be deprotonated: : These organolithium compounds degrade with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lipoic Acid
Lipoic acid (LA), also known as α-lipoic acid, alpha-lipoic acid (ALA) and thioctic acid, is an organosulfur compound derived from caprylic acid (octanoic acid). ALA, which is made in animals normally, is essential for aerobic metabolism. It is also available as a dietary supplement or pharmaceutical drug in some countries. Lipoate is the conjugate base of lipoic acid, and the most prevalent form of LA under physiological conditions. Only the (''R'')-(+)-enantiomer (RLA) exists in nature. RLA is an essential cofactor of many processes. Physical and chemical properties Lipoic acid contains two sulfur atoms connected by a disulfide bond in the 1,2-dithiolane ring. It also carries a carboxylic acid group. It is considered to be oxidized relative to its acyclic relative dihydrolipoic acid, in which each sulfur exists as a thiol. It is a yellow solid. (''R'')-(+)-lipoic acid (RLA) occurs naturally, but (''S'')-(-)-lipoic acid (SLA) has been synthesized. For use in dietary supp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1,3-propanedithiol
1,3-Propanedithiol is the chemical compound with the formula HSCH2CH2CH2SH. This dithiol is a useful reagent in organic synthesis. This liquid, which is readily available commercially, has an intense stench. Reactions 1,3-Propanedithiol has been used for the protection of aldehydes and ketones via their reversible formation of dithianes. A prototypical reaction is its formation of 1,3-dithiane from formaldehyde. The reactivity of this dithiane illustrates the concept of umpolung. Alkylation gives thioethers, e.g. 1,5-dithiacyclooctane. The unpleasant odour of 1,3-propanedithiol has encouraged the development of alternative reagents that generate similar derivatives. Oxidation gives not the 1,2-dithiolane, but the bis(disulfide). 1,3-Propanedithiol is used in the synthesis of tiapamil. 1,3-Propanedithiol reacts with metal ions to form dithiolates. Illustrative is the synthesis of the derivative diiron propanedithiolate hexacarbonyl upon reaction with triiron dodecacar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chara Globuluris
Chara may refer to: Places *Chara (river), a river in Russia *Chara (rural locality), a rural locality (a ''selo'') in Zabaykalsky Krai, Russia * Chara Airport, an airport in Russia near the rural locality * Chara Sands, a sanded area in Siberia, Russia Science * ''Chara'' (alga), a genus of algae in the family Characeae * ''Chara'' (moth), a genus of moths in the family Noctuidae *CHARA array, a telescope *Beta Canum Venaticorum or Chara, a star *Chara or Southern dogs, a constellation including Beta Canum Venaticorum and Cor Caroli People * Chara (given name) *Chara (singer), Japanese singer * Chara (surname) *Chara people, ethnic group in the Southern Nations, Nationalities, and Peoples' Region of Ethiopia Other uses * ''Chara'' (magazine), a Japanese Yaoi/Shōjo magazine *Chara language, the language of the Chara people * USS ''Chara'' (AKA-58), a 1944 Achernar class attack cargo ship * Chara (''Undertale''), a video game character See also *Charabanc, a type of vehicle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cassipourea Guianensis
''Cassipourea'' is a genus of flowering plants in the family Rhizophoraceae. There are about 40 species. The genus is divided into several subgenera, based mainly on the structure of the flowers.Kenfack, D. (2011)''Cassipourea atanganae'' sp. nov., a new species of Rhizophoraceae from Lower Guinea.''Adansonia'', 33(2), 209-213. Species include: * '' Cassipourea acuminata'' Liben * ''Cassipourea brittoniana'' Fawc. & Rendle * ''Cassipourea eketensis'' Baker f. * ''Cassipourea fanshawei'' Torre & Goncalves * ''Cassipourea flanaganii'' (Schinz) Alston * ''Cassipourea hiotou'' Aubrev. & Pellegrin * ''Cassipourea malosana'' (Baker) Alston * ''Cassipourea obovata'' Alston * ''Cassipourea subcordata'' Britton * ''Cassipourea subsessilis'' Britton * ''Cassipourea swaziensis'' Compton * ''Cassipourea thomassetii ''Cassipourea thomassetii'' is a species of plant in the Rhizophoraceae family. It is endemic to Seychelles. It is threatened by habitat loss Habitat destruction (also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tungsten Disulfide
Tungsten disulfide is an inorganic chemical compound composed of tungsten and sulfur with the chemical formula WS2. This compound is part of the group of materials called the transition metal dichalcogenides. It occurs naturally as the rare mineral ''tungstenite''. This material is a component of certain catalysts used for hydrodesulfurization and hydrodenitrification. WS2 adopts a layered structure similar, or isotypic with MoS2, instead with W atoms situated in trigonal prismatic coordination sphere (in place of Mo atoms). Owing to this layered structure, WS2 forms non-carbon nanotubes, which were discovered after heating a thin sample of WS2 in 1992. Structure and physical properties Bulk WS2 forms dark gray hexagonal crystals with a layered structure. Like the closely related MoS2, it exhibits properties of a dry lubricant. Although it has long been thought that WS2 is relatively stable in ambient air, recent reports on the ambient air oxidation of monolayer WS2 have found ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MoS2
Molybdenum disulfide (or moly) is an inorganic compound composed of molybdenum and sulfur. Its chemical formula is . The compound is classified as a transition metal dichalcogenide. It is a silvery black solid that occurs as the mineral molybdenite, the principal ore for molybdenum.Sebenik, Roger F. ''et al''. (2005) "Molybdenum and Molybdenum Compounds", ''Ullmann's Encyclopedia of Chemical Technology''. Wiley-VCH, Weinheim. is relatively unreactive. It is unaffected by dilute acids and oxygen. In appearance and feel, molybdenum disulfide is similar to graphite. It is widely used as a dry lubricant because of its low friction and robustness. Bulk is a diamagnetic, indirect bandgap semiconductor similar to silicon, with a bandgap of 1.23 eV. Production is naturally found as either molybdenite, a crystalline mineral, or jordisite, a rare low temperature form of molybdenite. Molybdenite ore is processed by flotation to give relatively pure . The main contaminant is carbon. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transition Metal Dichalcogenide Monolayers
Transition-metal dichalcogenide (TMD or TMDC) monolayers are atomically thin semiconductors of the type MX2, with M a transition metal, transition-metal atom (molybdenum, Mo, tungsten, W, etc.) and X a chalcogen atom (sulphur, S, selenium, Se, or tellurium, Te). One layer of M atoms is sandwiched between two layers of X atoms. They are part of the large family of so-called single-layer materials, 2D materials, named so to emphasize their extraordinary thinness. For example, a MoS2 monolayer is only 6.5 Å thick. The key feature of these materials is the interaction of large atoms in the 2D structure as compared with first-row transition-metal dichalcogenides, e.g., Tungsten ditelluride, WTe2 exhibits anomalous giant magnetoresistance and superconductivity. The discovery of graphene shows how new physical properties emerge when a bulk crystal of macroscopic dimensions is thinned down to one atomic layer. Like graphite, TMD bulk crystals are formed of monolayers bound to each ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nicotinic Acetylcholine Receptor
Nicotinic acetylcholine receptors, or nAChRs, are Receptor (biochemistry), receptor polypeptides that respond to the neurotransmitter acetylcholine. Nicotinic receptors also respond to drugs such as the agonist nicotine. They are found in the central and peripheral nervous system, muscle, and many other tissues of many organisms. At the neuromuscular junction they are the primary receptor in muscle for motor nerve-muscle communication that controls muscle contraction. In the peripheral nervous system: (1) they transmit outgoing signals from the presynaptic to the postsynaptic cells within the Sympathetic nervous system, sympathetic and parasympathetic nervous system, and (2) they are the receptors found on skeletal muscle that receive acetylcholine released to signal for muscular contraction. In the immune system, nAChRs regulate inflammatory processes and signal through distinct intracellular pathways. In insects, the cholinergic system is limited to the central nervous system. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
