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Scholl Reaction
The Scholl reaction is a coupling reaction between two arene compounds with the aid of a Lewis acid and a protic acid.Grzybowski, M., Skonieczny, K., Butenschön, H. and Gryko, D. T. (2013), ''Comparison of Oxidative Aromatic Coupling and the Scholl Reaction''. Angew. Chem. Int. Ed., 52: 9900–9930. It is named after its discoverer, Roland Scholl, a Swiss chemist. In 1910 Scholl reported the synthesis of a quinone and of perylene from naphthalene both with aluminum chloride. Perylene was also synthesised from 1,1’-binaphthalene in 1913. The synthesis of Benzanthrone was reported in 1912. The protic acid in the Scholl reaction is often an impurity in the Lewis Acid and also formed in the course of a Scholl reaction. Reagents are iron(III) chloride in dichloromethane, copper(II) chloride, PIFA and boron trifluoride etherate in dichloromethane, Molybdenum(V) chloride and lead tetraacetate with BF3 in acetonitrile.''Controlling the Scholl Reaction'' Benjamin T. King, Jií K ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Roland Scholl
Roland Heinrich Scholl (30 September 1865 – 22 August 1945) was a Swiss chemist who taught at various European universities. Among his most notable achievements are the synthesis of coronene, the co-development of the Bally-Scholl synthesis, and various discoveries about polycyclic aromatic hydrocarbons. Early life and education Roland Heinrich Scholl was born on 30 September 1865 in Zurich, Switzerland, the son of a Badensian merchant. After primary education by a Homeschooling, private teacher and secondary education at a Gymnasium (school), Gymnasium in Zurich, he studied chemistry and physics at the University of Würzburg in 1883. One of his teachers there was Johannes Wislicenus, his mother's brother. After military service in a Bavarian regiment, he continued his studies in 1885 at the ''Eidgenössisches Polytechnikum Zürich, Eidgenössisches Polytechnikum'' in Zurich. In 1890 he received a Doctor of Philosophy, Dr. phil. degree from the University of Basel. Life and c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetonitrile
Acetonitrile, often abbreviated MeCN (methyl cyanide), is the chemical compound with the formula and structure . This colourless liquid is the simplest organic nitrile (hydrogen cyanide is a simpler nitrile, but the cyanide anion is not classed as organic). It is produced mainly as a byproduct of acrylonitrile manufacture. It is used as a polar aprotic solvent in organic synthesis and in the purification of butadiene. The skeleton is linear with a short distance of 1.16 Å. Acetonitrile was first prepared in 1847 by the French chemist Jean-Baptiste Dumas. Applications Acetonitrile is used mainly as a solvent in the purification of butadiene in refineries. Specifically, acetonitrile is fed into the top of a distillation column filled with hydrocarbons including butadiene, and as the acetonitrile falls down through the column, it absorbs the butadiene which is then sent from the bottom of the tower to a second separating tower. Heat is then employed in the separatin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Suzuki Reaction
The Suzuki reaction is an organic reaction, classified as a cross-coupling reaction, where the coupling partners are a boronic acid and an organohalide and the catalyst is a palladium(0) complex. It was first published in 1979 by Akira Suzuki, and he shared the 2010 Nobel Prize in Chemistry with Richard F. Heck and Ei-ichi Negishi for their contribution to the discovery and development of palladium-catalyzed cross-couplings in organic synthesis. This reaction is also known as the Suzuki–Miyaura reaction or simply as the Suzuki coupling. It is widely used to synthesize poly olefins, styrenes, and substituted biphenyls. Several reviews have been published describing advancements and the development of the Suzuki reaction. The general scheme for the Suzuki reaction is shown below, where a carbon-carbon single bond is formed by coupling a halide (R1-X) with an organoboron species (R2-BY2) using a palladium catalyst and a base. Reaction mechanism The mechanism of the Suzuki r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triphenylene
Triphenylene is an organic compound with the formula (C6H4)3. A flat polycyclic aromatic hydrocarbon (PAH), it consists of four fused benzene rings. Triphenylene has delocalized 18-''π''-electron systems based on a planar structure, corresponding to the symmetry group ''D''3h. It is a white or colorless solid. Preparation Triphenylene can be isolated from coal tar. It is also be synthesized in various ways. One method is trimerization of benzyne. Another method involves trapping benzyne with a biphenyl derivative. Properties Triphenylene is more resonance stable than its isomers chrysene, benz 'a''nthracene, benzo 'c''henanthrene, and tetracene. For this reason triphenylene resists hydrogenation. As a disc-shaped, planar molecule, triphenylene has attracted attention as the core of discotic mesogen in liquid crystal Liquid crystal (LC) is a state of matter whose properties are between those of conventional liquids and those of solid crystals. For example, a liquid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polycyclic Aromatic Hydrocarbon
A polycyclic aromatic hydrocarbon (PAH) is a class of organic compounds that is composed of multiple aromatic rings. The simplest representative is naphthalene, having two aromatic rings and the three-ring compounds anthracene and phenanthrene. PAHs are uncharged, non-polar and planar. Many are colorless. Many of them are found in coal and in oil deposits, and are also produced by the combustion of organic matter—for example, in engines and incinerators or when biomass burns in forest fires. Polycyclic aromatic hydrocarbons are discussed as possible starting materials for abiotic syntheses of materials required by the earliest forms of life. Nomenclature and structure The terms polyaromatic hydrocarbon or polynuclear aromatic hydrocarbon are also used for this concept. By definition, polycyclic aromatic hydrocarbons have multiple rings, precluding benzene from being considered a PAH. Some sources, such as the US EPA and CDC, consider naphthalene to be the simplest PAH. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cascade Reaction
A cascade reaction, also known as a domino reaction or tandem reaction, is a chemical process that comprises at least two consecutive reactions such that each subsequent reaction occurs only in virtue of the chemical functionality formed in the previous step.Tietze, L. F.; Beifuss, U. ''Angew. Chem. Int. Ed.'' 1993, ''32'', 131–163. In cascade reactions, isolation of intermediates is not required, as each reaction composing the sequence occurs spontaneously. In the strictest definition of the term, the reaction conditions do not change among the consecutive steps of a cascade and no new reagents are added after the initial step.Padwa, A.; Bur, S. K. ''Tetrahedron'' 2007, ''63'', 5341–5378. By contrast, one-pot procedures similarly allow at least two reactions to be carried out consecutively without any isolation of intermediates, but do not preclude the addition of new reagents or the change of conditions after the first reaction. Thus, any cascade reaction is also a one-pot p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anthracene
Anthracene is a solid polycyclic aromatic hydrocarbon (PAH) of formula C14H10, consisting of three fused benzene rings. It is a component of coal tar. Anthracene is used in the Economic production, production of the red dye alizarin and other dyes. Anthracene is colorless but exhibits a blue (400–500 nm peak) fluorescence under ultraviolet radiation. Occurrence and production Coal tar, which contains around 1.5% anthracene, remains a major source of this material. Common impurities are phenanthrene and carbazole. The mineral form of anthracene is called freitalite and is related to a coal deposit. A classic laboratory method for the preparation of anthracene is by cyclodehydration of o-methyl- or o-methylene-substituted diarylketones in the so-called Elbs reaction, for example from ''o''-tolyl phenyl ketone. Reactions Reduction Reduction of anthracene with alkali metals yields the deeply colored radical anion salts M+[anthracene]− (M = Li, Na, K). Hydrogenation gives 9 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrene
Pyrene is a polycyclic aromatic hydrocarbon (PAH) consisting of four fused benzene rings, resulting in a flat aromatic system. The chemical formula is . This yellow solid is the smallest peri-fused PAH (one where the rings are fused through more than one face). Pyrene forms during incomplete combustion of organic compounds. Occurrence and properties Pyrene was first isolated from coal tar, where it occurs up to 2% by weight. As a peri-fused PAH, pyrene is much more resonance-stabilized than its five-member-ring containing isomer fluoranthene. Therefore, it is produced in a wide range of combustion conditions. For example, automobiles produce about 1 μg/km.Senkan, Selim and Castaldi, Marco (2003) "Combustion" in ''Ullmann's Encyclopedia of Industrial Chemistry'', Wiley-VCH, Weinheim. Reactions Oxidation with chromate affords perinaphthenone and then naphthalene-1,4,5,8-tetracarboxylic acid. Pyrene undergoes a series of hydrogenation reactions and is susceptible to halogen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorene
Fluorene , or 9''H''-fluorene is an organic compound with the formula (C6H4)2CH2. It forms white crystals that exhibit a characteristic, aromatic odor similar to that of naphthalene. It has a violet fluorescence, hence its name. For commercial purposes it is obtained from coal tar. It is insoluble in water and soluble in many organic solvents. Although sometimes classified as a polycyclic aromatic hydrocarbon, the five-membered ring has no aromatic properties. Fluorene is mildly acidic. Synthesis, structure, and reactivity Although fluorene is obtained from coal tar, it can also be prepared by dehydrogenation of diphenylmethane. Alternatively, it can be prepared by the reduction of fluorenone with zinc or hypophosphorous acid–iodine. The fluorene molecule is nearly planar,D. M. Burns, John Iball (1954), ''Molecular Structure of Fluorene'' Nature volume 173, p. 635. although each of the two benzene rings is coplanar with the central carbon 9. Fluorene can be found after the i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Synthesis
Organic synthesis is a special branch of chemical synthesis and is concerned with the intentional construction of organic compounds. Organic molecules are often more complex than inorganic compounds, and their synthesis has developed into one of the most important branches of organic chemistry. There are several main areas of research within the general area of organic synthesis: ''total synthesis'', ''semisynthesis'', and ''methodology''. Total synthesis A total synthesis is the complete chemical synthesis of complex organic molecules from simple, commercially available petrochemical or natural precursors. Total synthesis may be accomplished either via a linear or convergent approach. In a ''linear'' synthesis—often adequate for simple structures—several steps are performed one after another until the molecule is complete; the chemical compounds made in each step are called synthetic intermediates. Most often, each step in a synthesis refers to a separate rea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
