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Bamberger Rearrangement
The Bamberger rearrangement is the chemical reaction of phenylhydroxylamines with strong aqueous acid, which will rearrange to give 4-aminophenols. It is named for the German chemist Eugen Bamberger (1857–1932). The starting phenylhydroxylamines are typically synthesized by the transfer hydrogenation of nitrobenzenes using rhodium or zinc catalysts. Application: Fenhexamide Reaction mechanism The mechanism of the Bamberger rearrangement proceeds from the monoprotonation of N-phenylhydroxylamine 1. N-protonation 2 is favored, but unproductive. O-protonation 3 can form the nitrenium ion 4, which can react with nucleophiles ( H2O) to form the desired 4-aminophenol 5. See also * Friedel–Crafts alkylation-like reactions: ** Hofmann-Martius rearrangement **Fries rearrangement The Fries rearrangement, named for the German chemist Karl Theophil Fries, is a rearrangement reaction of a phenolic ester to a hydroxy aryl ketone by catalysis of Lewis acids. It involves mi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Reaction
A chemical reaction is a process that leads to the IUPAC nomenclature for organic transformations, chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking of chemical bonds between atoms, with no change to the Atomic nucleus, nuclei (no change to the elements present), and can often be described by a chemical equation. Nuclear chemistry is a sub-discipline of chemistry that involves the chemical reactions of unstable and radioactive Chemical element, elements where both electronic and nuclear changes can occur. The substance (or substances) initially involved in a chemical reaction are called reagent, reactants or reagents. Chemical reactions are usually characterized by a chemical change, and they yield one or more Product (chemistry), products, which usually have properties different from the reactants. Reactions often consist of a sequence o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wallach Rearrangement
The Wallach rearrangement, also named ''Wallach transformation'', is a name reaction in the organic chemistry. It is named after Otto Wallach, who discovered this reaction in 1880. In general it is a strong acid-promoted conversion of azoxybenzenes into hydroxyazobenzenes.Otto Wallach and E. Belli, Chem. Ber., 13, 525 (1880) General reaction scheme The Wallach rearrangement is an organic reaction converting an aromatic azoxy compound with sulfuric acid or other strong acids to an azo compound with one arene ring substituted by a hydroxyl group in the aromatic para position. Conceptually related reactions are the Fries rearrangement, the Fischer–Hepp rearrangement, the Bamberger rearrangement, the benzidine rearrangement and the Hofmann–Martius rearrangement. In the first part of the reaction, two equivalents of acid tease the oxygen atom away from the azoxy group. The resulting dicationic intermediate with an unusual R–N+=N+–R motif in this scheme has been observed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fischer–Hepp Rearrangement
The Fischer–Hepp rearrangement is a rearrangement reaction in which an aromatic N-nitroso or nitrosamine converts to a carbon nitroso compound: This organic reaction was first described by the German chemist Otto Philipp Fischer (1852–1932) and Eduard Hepp (June 11, 1851 – June 18, 1917) W Pötsch. ''Lexikon bedeutender Chemiker'' (VEB Bibliographisches Institut Leipzig, 1989) in 1886, and is of importance because para- NO secondary anilines cannot be prepared in a direct reaction. The rearrangement reaction takes place by reacting the nitrosamine precursor with hydrochloric acid. The chemical yield is generally good under these conditions, but often much poorer if a different acid is used. The exact reaction mechanism is unknown but there is evidence suggesting an intramolecular reaction. Sources''Named Things in Chemical Industry'' See also * Friedel–Crafts alkylation-like reactions: ** Hofmann-Martius rearrangement **Fries rearrangement The Fries rearrangement, n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fries Rearrangement
The Fries rearrangement, named for the German chemist Karl Theophil Fries, is a rearrangement reaction of a phenolic ester to a hydroxy aryl ketone by catalysis of Lewis acids. It involves migration of an acyl group of phenol ester to the aryl ring. The reaction is ortho and para selective and one of the two products can be favoured by changing reaction conditions, such as temperature and solvent. Mechanism Despite many efforts, a definitive reaction mechanism for the Fries rearrangement has not been determined. Evidence for inter- and intramolecular mechanisms have been obtained by crossover experiments with mixed reactants. The reaction progress is not dependent on solvent or substrate. A widely accepted mechanism involves a carbocation intermediate. In the first reaction step a Lewis acid for instance aluminium chloride co-ordinates to the carbonyl oxygen atom of the acyl group. This oxygen atom is more electron rich than the phenolic oxygen atom and is the preferred ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bamberger Rearrangement Mechanism V1
Bamberger is a Bavarian and Southern German toponymic surname, and it indicates someone from Bamberg in Bavaria. Notable people with the surname include: * Ana Maria Bamberger (born 1966), Romanian physician and playwright * Ármin Vámbéry (born Bamberger) (1832–1913), Hungarian orientalist * Bernard Jacob Bamberger (1904-1980), American rabbi and Biblical scholar * Cyril Stanley Bamberger (1919–2008), Battle of Britain pilot * Eugen Bamberger (1857–1932), German chemist * Florence E. Bamberger (1882–1965), American pedagogue * Fritz Bamberger (painter) (1814–1873), German painter * Fritz Bamberger (scholar) (1902–1984), German Jewish scholar * Heinrich von Bamberger, Austrian physician * George Bamberger (1923–2004), American baseball player * Jakob Bamberger (1913–1989), German boxer and Porajmos survivor * Lesley Bamberger (born 1965/1966), Dutch billionaire, owner of Kroonenberg Groep * Louis Bamberger (1855-1944), founder of the Institute for Advanced Study ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of The Chemical Society, Perkin Transactions 2
Perkin Transactions is a scientific journal devoted to organic chemistry published from 1997 to 2002 by the Royal Society of Chemistry. It was split into ''Perkin Transactions I'' and ''Perkin Transactions II''. The predecessor journals published by the Chemical Society before the merger of that Society with other Societies to form the Royal Society of Chemistry were the ''Journal of the Chemical Society, Perkin Transactions 1'' and ''Journal of the Chemical Society, Perkin Transactions 2'' (1972-1996). They were replaced by ''Organic and Biomolecular Chemistry''. The name honours the chemist Arthur George Perkin. See also * List of scientific journals in chemistry * List of scientific journals External links * Royal Society of Chemistry'Website for Perkin 1* Royal Society of Chemistry The Royal Society of Chemistry (RSC) is a learned society (professional association) in the United Kingdom with the goal of "advancing the chemical sciences". It was formed in 1980 from the am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water (molecule)
Water () is a Chemical polarity, polar inorganic compound that is at room temperature a tasteless and odorless liquid, which is nearly colorless apart from Color of water, an inherent hint of blue. It is by far the most studied chemical compound and is described as the "universal solvent" and the "solvent of life". It is the most abundant substance on the surface of Earth and the only common substance to exist as a ice, solid, liquid, and water vapor, gas on Earth's surface. It is also the third most abundant molecule in the universe (behind Hydrogen, molecular hydrogen and carbon monoxide). Water molecules form hydrogen bonds with each other and are strongly polar. This polarity allows it to dissociate ions in salts and bond to other polar substances such as alcohols and acids, thus dissolving them. Its hydrogen bonding causes its many unique properties, such as having a solid form less dense than its liquid form, a relatively high boiling point of 100 °C for its molar m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrenium Ion
A nitrenium ion (also called: aminylium ion or imidonium ion (obsolete)) in organic chemistry is a reactive intermediate based on nitrogen with both an electron lone pair and a positive charge and with two substituents (). Nitrenium ions are isoelectronic with carbenes, and can exist in either a singlet or a triplet state. The parent nitrenium ion, , is a ground state triplet species with a gap of to the lowest energy singlet state. Conversely, most arylnitrenium ions are ground state singlets. Certain substituted arylnitrenium ions can be ground state triplets, however. Nitrenium ions can have microsecond or longer lifetimes in water. Aryl nitrenium ions are of biological interest because of their involvement in certain DNA damaging processes. They are generated upon ''in vivo'' oxidation of arylamines. The regiochemistry and energetics of the reaction of phenylnitrenium ion with guanine has been investigated using density functional theory computations. Nitrenium species hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zinc
Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodic table. In some respects, zinc is chemically similar to magnesium: both elements exhibit only one normal oxidation state (+2), and the Zn2+ and Mg2+ ions are of similar size.The elements are from different metal groups. See periodic table. Zinc is the 24th most abundant element in Earth's crust and has five stable isotopes. The most common zinc ore is sphalerite (zinc blende), a zinc sulfide mineral. The largest workable lodes are in Australia, Asia, and the United States. Zinc is refined by froth flotation of the ore, roasting, and final extraction using electricity ( electrowinning). Zinc is an essential trace element for humans, animals, plants and for microorganisms and is necessary for prenatal and postnatal development. It ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
