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Benzothiazole
Benzothiazole is an aromatic heterocyclic compound with the chemical formula . It is colorless, slightly viscous liquid. Although the parent compound, benzothiazole is not widely used, many of its derivatives are found in commercial products or in nature. Firefly luciferin can be considered a derivative of benzothiazole. Structure and preparation Benzothiazoles consist of a 5-membered 1,3-thiazole ring fused to a benzene ring. The nine atoms of the bicycle and the attached substituents are coplanar. Benzothiazoles are prepared by treatment of 2-mercaptoaniline with acid chlorides: :C6H4(NH2)SH + RC(O)Cl → C6H4(NH)SCR + HCl + H2O Uses Benzothiazole occurs naturally in some foods but is also used as a food additive. It has a sulfurous odor and meaty flavor. The European Food Safety Authority assessment had "no safety concern at estimated levels of intake as a flavouring substance". The heterocyclic core of the molecule is readily substituted at the unique methyne ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benzothiazoles
Benzothiazole is an aromatic heterocyclic compound with the chemical formula . It is colorless, slightly viscous liquid. Although the parent compound, benzothiazole is not widely used, many of its derivatives are found in commercial products or in nature. Firefly luciferin can be considered a derivative of benzothiazole. Structure and preparation Benzothiazoles consist of a 5-membered 1,3-thiazole ring fused to a benzene ring. The nine atoms of the bicycle and the attached substituents are coplanar. Benzothiazoles are prepared by treatment of 2-mercaptoaniline with acid chlorides: :C6H4(NH2)SH + RC(O)Cl → C6H4(NH)SCR + HCl + H2O Uses Benzothiazole occurs naturally in some foods but is also used as a food additive. It has a sulfurous odor and meaty flavor. The European Food Safety Authority assessment had "no safety concern at estimated levels of intake as a flavouring substance". The heterocyclic core of the molecule is readily substituted at the unique methyne ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2-mercaptobenzothiazole
2-Mercaptobenzothiazole is an organosulfur compound with the formula . It is used in the sulfur vulcanization of rubber. Structure The molecule is planar with a C=S double bond, so the name ''mercapto''benzothiazole is a misnomer. It is not a thiol, but instead is a thioamide, in the solid state, gas-phase, and in solution. A more appropriate name is benzothiazoline-2-thione. Solution measurements by NMR spectroscopy reveal no evidence for the thiol tautomer. Theory also indicates that the thiol tautomer is about 39 kJ/mol higher in energy than the thioamide. Synthesis and reactions The compound has been produced by many methods. The industrial route entails the high temperature reaction of aniline and carbon disulfide in the presence of sulfur, which proceeds by this idealized equation: : The traditional route is the reaction of 2-aminothiophenol and carbon disulfide: : This method was developed by the discoverer of the compound, A. W. Hoffmann. Other routes developed by Hof ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thioflavin
Thioflavins are fluorescent dyes that are available as at least two compounds, namely Thioflavin T and Thioflavin S. Both are used for histology staining and biophysics, biophysical studies of protein aggregation. In particular, these dyes have been used since 1989 to investigate amyloid formation. They are also used in biophysical studies of the electrophysiology of bacteria. Thioflavins are corrosive, Irritation, irritants, and are acutely toxic, causing serious eye damage. Thioflavin T has been used in research into Alzheimer's disease and other neurodegenerative diseases. Thioflavin T Thioflavin T (Basic Yellow 1, Methylene yellow, CI 49005, or ThT) is a benzothiazole salt obtained by the methylation of dehydrothiotoluidine with methanol in the presence of hydrochloric acid. The dye is widely used to visualize and quantify the presence of misfolded protein aggregates called amyloid, both ''in vitro'' and ''in vivo'' (e.g., Senile plaques, plaques composed of amyloid beta found ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Firefly Luciferin
Firefly luciferin (also known as beetle luciferin) is the luciferin, or light-emitting compound, used for the firefly (Lampyridae), railroad worm (Phengodidae), starworm (Rhagophthalmidae), and click-beetle (Pyrophorini) bioluminescent systems. It is the substrate of luciferase (Enzyme Commission number, EC 1.13.12.7), which is responsible for the characteristic yellow light emission from many firefly species. As with all other luciferins, oxygen is required to elicit light; however, it has also been found adenosine triphosphate (ATP) and magnesium are required for light emission. History Much of the early work on the chemistry of the firefly luminescence was done in the lab of William D. McElroy at Johns Hopkins University. The luciferin was first isolated and purified in 1949, though it would be several years until a procedure was developed to crystallize the compound in high yield. This, along with the synthesis and structure elucidation, was accomplished by Dr. Emil H. White ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benzoxazole
Benzoxazole is an aromatic organic compound with a molecular formula C7H5NO, a benzene-fused oxazole ring structure, and an odor similar to pyridine. Although benzoxazole itself is of little practical value, many derivatives of benzoxazoles are commercially important. Being a heterocyclic compound, benzoxazole finds use in research as a starting material for the synthesis of larger, usually bioactive structures. Its aromaticity makes it relatively stable, although as a heterocycle, it has reactive sites which allow for functionalization. Occurrence and applications It is found within the chemical structures of pharmaceutical drugs such as flunoxaprofen and tafamidis. Benzoxazole derivatives are also of interest for optical brighteners in laundry detergents.E. Smulders, E. Sung "Laundry Detergents, 2. Ingredients and Products" in ''Ullmann's Encyclopedia of Industrial Chemistry'', Wiley-VCH, Weinheim, 2012. Benzoxazoles belong to the group of well-known antifungal agents with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Riluzole
Riluzole is a medication used to treat amyotrophic lateral sclerosis and other motor neuron diseases. Riluzole delays the onset of ventilator-dependence or tracheostomy in some people and may increase survival by two to three months. Riluzole is available in tablet and liquid form. Medical use Amyotrophic lateral sclerosis Riluzole was approved in the United States for the treatment of ALS by the U.S. Food and Drug Administration (FDA) in 1995. A Cochrane Library review states a 9% gain in the probability of surviving one year. Adverse effects * Very common (>10% frequency): nausea; weakness; decreased lung function * Common (1–10% frequency): headache; dizziness; drowsiness; vomiting; abdominal pain; increased aminotransferases * Uncommon (0.1-1% frequency): pancreatitis; interstitial lung disease * Rare (<0.1% frequency): ; all ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aromatic
In chemistry, aromaticity is a chemical property of cyclic ( ring-shaped), ''typically'' planar (flat) molecular structures with pi bonds in resonance (those containing delocalized electrons) that gives increased stability compared to saturated compounds having single bonds, and other geometric or connective non-cyclic arrangements with the same set of atoms. Aromatic rings are very stable and do not break apart easily. Organic compounds that are not aromatic are classified as aliphatic compounds—they might be cyclic, but only aromatic rings have enhanced stability. The term ''aromaticity'' with this meaning is historically related to the concept of having an aroma, but is a distinct property from that meaning. Since the most common aromatic compounds are derivatives of benzene (an aromatic hydrocarbon common in petroleum and its distillates), the word ''aromatic'' occasionally refers informally to benzene derivatives, and so it was first defined. Nevertheless, many ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nonlinear Optics
Nonlinear optics (NLO) is the branch of optics that describes the behaviour of light in ''nonlinear media'', that is, media in which the polarization density P responds non-linearly to the electric field E of the light. The non-linearity is typically observed only at very high light intensities (when the electric field of the light is >108 V/m and thus comparable to the atomic electric field of ~1011 V/m) such as those provided by lasers. Above the Schwinger limit, the vacuum itself is expected to become nonlinear. In nonlinear optics, the superposition principle no longer holds. History The first nonlinear optical effect to be predicted was two-photon absorption, by Maria Goeppert Mayer for her PhD in 1931, but it remained an unexplored theoretical curiosity until 1961 and the almost simultaneous observation of two-photon absorption at Bell Labs and the discovery of second-harmonic generation by Peter Franken ''et al.'' at University of Michigan, both shortly after the constru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfur Vulcanization
Sulfur vulcanization is a chemical process for converting natural rubber or related polymers into materials of varying hardness, elasticity, and mechanical durability by heating them with sulfur or sulfur-containing compounds. Sulfur forms cross-linking bridges between sections of polymer chains which affects the mechanical and electronic properties. Many products are made with vulcanized rubber, including tires, shoe soles, hoses, and conveyor belts. The term is derived from Vulcan, the Roman god of fire. The main polymers subjected to sulfur vulcanization are polyisoprene (natural rubber, NR), polybutadiene rubber (BR) and styrene-butadiene rubber (SBR), and ethylene propylene diene monomer rubber ( EPDM rubber). All of these materials contain alkene groups adjacent to methylene groups. Other specialty rubbers may also be vulcanized, such as nitrile rubber (NBR) and butyl rubber (IIR). Vulcanization, in common with the curing of other thermosetting polymers, is generally ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pramipexole
Pramipexole, sold under the brand Mirapex among others, is medication used to treat Parkinson's disease (PD) and restless legs syndrome (RLS). In Parkinson's disease it may be used alone or together with levodopa. It is taken by mouth. Pramipexole is a dopamine agonist of the non-ergoline class. Studies have shown detrimental side effects resulting from off-label use of pramipexole or other dopamine agonists in treating clinical depression. Pramipexole was approved for medical use in the United States in 1997. Use in pregnancy and breastfeeding is of unclear safety. It is available as a generic medication. In 2020, it was the 193rd most commonly prescribed medication in the United States, with more than 2million prescriptions. Medical uses Pramipexole is used in the treatment of Parkinson's disease (PD) and restless legs syndrome (RLS). Use in pregnancy and breastfeeding is of unclear safety. It is occasionally prescribed off-label for depression. Its effectiveness as an an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methine Group
In organic chemistry, a methine group or methine bridge is a trivalent functional group , derived formally from methane. It consists of a carbon atom bound by two single bonds and one double bond, where one of the single bonds is to a hydrogen. The group is also called methyne or methene; its IUPAC systematic name is methylylidene or methanylylidene (2007''Methanylylidene group''in the Chemical Entities of Biological Interest (ChEBI) database. Accessed on 2015-03-05. This group is sometimes called "methylidyne", however that name belongs properly to either the methylidyne group (connected to the rest of the molecule by a triple bond) or to the methylidyne radical (the two atoms as a free molecule with dangling bonds). The name "methine" is also widely used in non-systematic nomenclature for the methanetriyl group (IUPAC): a carbon atom with four single bonds, where one bond is to a hydrogen (). (2007''Methanetriyl group''in the Chemical Entities of Biological Interest (Ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterocyclic Compound
A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different elements as members of its ring(s). Heterocyclic chemistry is the branch of organic chemistry dealing with the synthesis, properties, and applications of these heterocycles. Examples of heterocyclic compounds include all of the nucleic acids, the majority of drugs, most biomass (cellulose and related materials), and many natural and synthetic dyes. More than half of known compounds are heterocycles. 59% of US FDA-approved drugs contain nitrogen heterocycles. Classification The study of heterocyclic chemistry focuses especially on unsaturated derivatives, and the preponderance of work and applications involves unstrained 5- and 6-membered rings. Included are pyridine, thiophene, pyrrole, and furan. Another large class of heterocycles refers to those fused to benzene rings. For example, the fused benzene derivatives of pyridine, thiophene, pyrrole, and furan are quinol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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