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Grob Fragmentation
In chemistry Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science that covers the Chemical element, elements that make up matter to the chemical compound, compounds made of atoms, molecules and ions ..., a Grob fragmentation is an elimination reaction that breaks a neutral aliphatic chain into three fragments: a cation, positive ion spanning atoms 1 and 2 (the "electrofuge"), an unsaturated hydrocarbon, unsaturated neutral fragment spanning positions 3 and 4, and a anion, negative ion (the "nucleofuge") comprising the rest of the chain. For example, the positive ion may be a carbenium ion, carbenium, carbonium ion, carbonium or acylium ion; the neutral fragment could be an alkene, alkyne, or imine; and the negative fragment could be a tosyl or hydroxyl ion: The reaction is named for the Swiss chemist . Alternately, atom 1 could begin as an anion, in which case it becomes neutral rather than going from neutral to cation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemistry
Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science that covers the Chemical element, elements that make up matter to the chemical compound, compounds made of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during a Chemical reaction, reaction with other Chemical substance, substances. Chemistry also addresses the nature of chemical bonds in chemical compounds. In the scope of its subject, chemistry occupies an intermediate position between physics and biology. It is sometimes called the central science because it provides a foundation for understanding both Basic research, basic and Applied science, applied scientific disciplines at a fundamental level. For example, chemistry explains aspects of plant growth (botany), the formation of igneous rocks (geology), how atmospheric ozone is formed and how environmental pollutants are degraded (ecology), the properties ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tosyl
In organic chemistry, a toluenesulfonyl group (tosyl group, abbreviated Ts or Tos) is a univalent functional group with the chemical formula –. It consists of a tolyl group, –, joined to a sulfonyl group, ––, with the open valence on sulfur. This group is usually derived from the compound tosyl chloride, (abbreviated TsCl), which forms esters and amides of toluenesulfonic acid, (abbreviated TsOH). The para orientation illustrated (''p''-toluenesulfonyl) is most common, and by convention ''tosyl'' without a prefix refers to the ''p''-toluenesulfonyl group. The toluenesulfonate (or tosylate) group refers to the – (TsO–) group, with an additional oxygen attached to sulfur and open valence on an oxygen. In a chemical name, the term ''tosylate'' may either refer to the salts containing the anion of ''p''-toluenesulfonic acid, (M = alkali metal, , , etc), or it may refer to esters of ''p''-toluenesulfonic acid, TsOR (R = organyl group). Applications For SN2 react ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aldol Adduct
The aldol reaction is a means of forming carbon–carbon bonds in organic chemistry. Discovered independently by the Russian chemist Alexander Borodin in 1869 and by the French chemist Charles-Adolphe Wurtz in 1872, the reaction combines two carbonyl compounds (the original experiments used aldehydes) to form a new β-hydroxy carbonyl compound. These products are known as ''aldols'', from the ''ald''ehyde + alcoh''ol'', a structural motif seen in many of the products. Aldol structural units are found in many important molecules, whether naturally occurring or synthetic. For example, the aldol reaction has been used in the large-scale production of the commodity chemical pentaerythritol and the synthesis of the heart disease drug Lipitor (atorvastatin, calcium salt). The aldol reaction unites two relatively simple molecules into a more complex one. Increased complexity arises because up to two new stereogenic centers (on the Alpha carbon, α- and β-carbon of the aldol adduct, mar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Albert Eschenmoser
Albert Jakob Eschenmoser (born 5 August 1925) is a Swiss organic chemist, best known for his work on the synthesis of complex heterocyclic natural compounds, most notably vitamin B12. In addition to his significant contributions to the field of organic synthesis, Eschenmoser pioneered work in the Origins of Life (OoL) field with work on the synthetic pathways of artificial nucleic acids. Before retiring in 2009, Eschenmoser held tenured teaching positions at the ETH Zurich and The Skaggs Institute for Chemical Biology at The Scripps Research Institute in La Jolla, California as well as visiting professorships at the University of Chicago, Cambridge University, and Harvard. Early work and Vitamin B12 Synthesis Eschenmoser began his scientific career as a graduate student in the laboratory of Leopold Ružička, at the Eidgenossische Technische Hochschule (ETH) in Zurich. Ruzicka was a notable organic chemist himself having been awarded the Nobel Prize in Chemistry in 1939 for his ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grob Fragmentation Whitmore 1933
Grob may refer to: * Grob Aerospace, a German aircraft manufacturer * Grob fragmentation, an elimination reaction between an electrofuge and nucleofuge on an aliphatic chain * GrOb or Grazhdanskaya Oborona, a Russian punk band People with the surname * Charles Grob, professor of psychiatry * Connie Grob (1932-1997), American baseball player * Henri Grob (1904–1974), Swiss chess master * Jakob Grob (born 1939), Swiss rower * Jeffrey S. Grob, American Roman Catholic bishop * Konrad Grob (1828–1904), Swiss painter * Therese Grob (1798–1875), first love of Franz Schubert See also * Chorvátsky Grob, a village and municipality in western Slovakia in Senec District in the Bratislava region * Slovenský Grob, a village and municipality in western Slovakia in Pezinok District in the Bratislava region * Veľký Grob, a village and municipality in Galanta District of the Trnava Region of south-west Slovakia * Grob's Attack, an opening in Chess * Gertrude Grob-Prandl Gertrude Grob-Pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rearrangement Reaction
In organic chemistry, a rearrangement reaction is a broad class of organic reactions where the carbon skeleton of a molecule is rearranged to give a structural isomer of the original molecule. Often a substituent moves from one atom to another atom in the same molecule, hence these reactions are usually intramolecular. In the example below, the substituent R moves from carbon atom 1 to carbon atom 2: :\underset\ce\ce\underset\ce\ce Intermolecular rearrangements also take place. A rearrangement is not well represented by simple and discrete electron transfers (represented by curved arrows in organic chemistry texts). The actual mechanism of alkyl groups moving, as in Wagner-Meerwein rearrangement, probably involves transfer of the moving alkyl group fluidly along a bond, not ionic bond-breaking and forming. In pericyclic reactions, explanation by orbital interactions give a better picture than simple discrete electron transfers. It is, nevertheless, possible to draw the curv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbocation
A carbocation is an ion with a positively charged carbon atom. Among the simplest examples are the methenium , methanium and vinyl cations. Occasionally, carbocations that bear more than one positively charged carbon atom are also encountered (e.g., ethylene dication ). Until the early 1970s, all carbocations were called ''carbonium ions''. In the present-day definition given by the IUPAC, a carbocation is any even-electron cation with significant partial positive charge on a carbon atom. They are further classified in two main categories according to the coordination number of the charged carbon: three in the carbenium ions and five in the carbonium ions. This nomenclature was proposed by G. A. Olah. Carbonium ions, as originally defined by Olah, are characterized by a three-center two-electron delocalized bonding scheme and are essentially synonymous with so-called 'non-classical carbocations', which are carbocations that contain bridging C–C or C–H σ-bonds. Howe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of The American Chemical Society
The ''Journal of the American Chemical Society'' is a weekly peer-reviewed scientific journal that was established in 1879 by the American Chemical Society. The journal has absorbed two other publications in its history, the ''Journal of Analytical and Applied Chemistry'' (July 1893) and the ''American Chemical Journal'' (January 1914). It covers all fields of chemistry. Since 2021, the editor-in-chief is Erick M. Carreira (ETH Zurich). In 2014, the journal moved to a hybrid open access publishing model. Abstracting and indexing The journal is abstracted and indexed in Chemical Abstracts Service, Scopus, EBSCO databases, ProQuest databases, Index Medicus/MEDLINE/PubMed, and the Science Citation Index Expanded. According to the ''Journal Citation Reports'', the journal has a 2021 impact factor of 16.383. Editors-in-chief The following people are or have been editor-in-chief: * 1879–1880 – Hermann Endemann * 1880–1881 – Gideon E. Moore * 1881–1882 – Hermann Endemann ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frank C
Frank or Franks may refer to: People * Frank (given name) * Frank (surname) * Franks (surname) * Franks, a medieval Germanic people * Frank, a term in the Muslim world for all western Europeans, particularly during the Crusades - see Farang Currency * Liechtenstein franc or frank, the currency of Liechtenstein since 1920 * Swiss franc or frank, the currency of Switzerland since 1850 * Westphalian frank, currency of the Kingdom of Westphalia between 1808 and 1813 * The currencies of the German-speaking cantons of Switzerland (1803–1814): ** Appenzell frank ** Argovia frank ** Basel frank ** Berne frank ** Fribourg frank ** Glarus frank ** Graubünden frank ** Luzern frank ** Schaffhausen frank ** Schwyz frank ** Solothurn frank ** St. Gallen frank ** Thurgau frank ** Unterwalden frank ** Uri frank ** Zürich frank Places * Frank, Alberta, Canada, an urban community, formerly a village * Franks, Illinois, United States, an unincorporated community * Franks, Missouri, United ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isobutene
Isobutylene (or 2-methylpropene) is a hydrocarbon with the chemical formula . It is a four-carbon branched alkene (olefin), one of the four isomers of butylene. It is a colorless flammable gas, and is of considerable industrial value. Production Polymer and chemical grade isobutylene is typically obtained by dehydrating tertiary butyl alcohol (TBA) or catalytic dehydrogenation of isobutane (Catofin or similar processes).. Gasoline additives methyl tert-butyl ether (MTBE) and ethyl tert-butyl ether (ETBE), respectively, are produced by reacting methanol or ethanol with isobutylene contained in butene streams from olefin steam crackers or refineries, or with isobutylene from dehydrated TBA. Isobutylene is not isolated from the olefin or refinery butene stream before the reaction, as separating the ethers from the remaining butenes is simpler. Isobutylene can also be produced in high purities by "back-cracking" MTBE or ETBE at high temperatures and then separating the isobutylene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2-methyl-2-butene
2-Methyl-2-butene, 2m2b, 2-methylbut-2-ene, also beta-isoamylene is an alkene hydrocarbon with the molecular formula C5H10. Used as a free radical scavenger in trichloromethane (chloroform) and dichloromethane (methylene chloride). John Snow, the English physician, experimented with it in the 1840s as an anesthetic, but stopped using it for unknown reasons. See also *Pentene Pentenes are alkenes with the chemical formula . Each contains one double bond within its molecular structure. Six different compounds are in this class, differing from each other by whether the carbon atoms are attached linearly or in a branched ... References Hydrocarbons Alkenes {{hydrocarbon-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Di(tert-butyl)methanol
Di or DI may refer to: Arts and media Music * Di, a tone in the solfège ascending chromatic scale existing between Do and Re * dizi (instrument) or di, a Chinese transverse flute * ''D.I.'' (band), a punk band from Southern California ** ''D.I.'' (EP), a 1983 EP by the same band above Other media * ''The D.I.'', 1957 military film by Jack Webb * '' Dagens Industri'', a Swedish financial newspaper * DI.FM, an internet radio service Businesses and organisations * Defence Intelligence, a UK military intelligence agency * Defensa Interior, an anti-Franco militant anarchist group in 1960s Spain * Deseret Industries, an LDS thrift store * Desert Inn, a former casino in Las Vegas * Direction Italy, a liberal-conservative political party in Italy * Dirgantara Indonesia, an Indonesian aircraft company * Discovery Institute, an intelligent design advocacy group * Norwegian Air UK, a UK based airline (IATA designator) * DynCorp International, a major United States defense contract ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
