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Chugaev Elimination
The Chugaev elimination is a chemical reaction that involves the elimination of water from alcohols to produce alkenes. The intermediate is a xanthate. It is named for its discoverer, the Russian chemist Lev Aleksandrovich Chugaev (1873-1922), who first reported the reaction sequence in 1899. In the first step, a xanthate salt is formed out of the alkoxide and carbon disulfide (CS2). With the addition of iodomethane, the alkoxide is transformed into a methyl xanthate. At about 200 °C, the alkene is formed by an intramolecular elimination. In a 6-membered cyclic transition state the hydrogen atom is removed from the carbon atom β to the xanthate oxygen in a ''syn''-elimination. The side product decomposes to carbonyl sulfide (OCS) and methanethiol. The Chugaev elimination is similar in mechanism to other thermal elimination reactions such as the Cope elimination and ester pyrolysis. Xanthates typically undergo elimination from 120 to 200 °C, while esters typical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lev Chugaev
Lev Aleksandrovich Chugaev (16 October 1873 – 26 September 1922) was a Russian chemist. At the height of his career, he was professor of chemistry at the University of Petersburg, being the successor to Dmitri Mendeleev. He was active in the fields of inorganic chemistry, especially platinum group Complex (chemistry), complexes, as well as organic chemistry. He is also known as Leo Aleksandrovich Tschugaeff or Tschugaev. Contributions to coordination chemistry Chugaev discovered that dimethylglyoxime forms a scarlet solid upon reaction with nickel(II) ions. This reaction was one of the first "spot tests" for a metal ion. An adherent to the theories of Alfred Werner, Chugaev made several contributions to the chemistry of platinum. The salt [Pt(NH3)5Cl]Cl3 containing the chloropentammineplatinum(IV) ion, is called "Chugaev's salt". Other complexes prepared in his laboratory include [Pt(Diethyl sulfide, SEt2)4][PtCl4], [Pt(NH3)5OH]Cl3, [Os(thiourea, SC(NH2)2)6]Cl3.H2O. Chugae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbonyl Sulfide
Carbonyl sulfide is the chemical compound with the linear formula OCS. It is a colorless flammable gas with an unpleasant odor. It is a linear molecule consisting of a carbonyl group double bonded to a sulfur atom. Carbonyl sulfide can be considered to be intermediate between carbon dioxide and carbon disulfide, both of which are valence isoelectronic with it. Occurrence Carbonyl sulfide is the most abundant sulfur compound naturally present in the atmosphere, at , because it is emitted from oceans, volcanoes and deep sea vents. As such, it is a significant compound in the global sulfur cycle. Measurements on the Antarctica ice cores and from air trapped in snow above glaciers (firn air) have provided a detailed picture of OCS concentrations from 1640 to the present day and allow an understanding of the relative importance of anthropogenic and non-anthropogenic sources of this gas to the atmosphere. Some carbonyl sulfide that is transported into the stratospheric sulfate lay ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elimination Reactions
Elimination may refer to: Science and medicine *Elimination reaction, an organic reaction in which two functional groups split to form an organic product *Bodily waste elimination, discharging feces, urine, or foreign substances from the body via defecation, urination, and emesis *Drug elimination, clearance of a drug or other foreign agent from the body *Elimination, the destruction of an infectious disease in one region of the world as opposed to its eradication from the entire world *Hazard elimination, the most effective type of hazard control * Elimination (pharmacology), processes by which a drug is eliminated from an organism Logic and mathematics * Elimination theory, the theory of the methods to eliminate variables between polynomial equations. * Disjunctive syllogism, a rule of inference * Gaussian elimination, a method of solving systems of linear equations * Fourier–Motzkin elimination, an algorithm for reducing systems of linear inequalities * Process of elim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Berichte Der Deutschen Chemischen Gesellschaft
''Chemische Berichte'' (usually abbreviated as ''Ber.'' or ''Chem. Ber.'') was a German-language scientific journal of all disciplines of chemistry founded in 1868. It was one of the oldest scientific journals in chemistry, until it merged with ''Recueil des Travaux Chimiques des Pays-Bas'' to form ''Chemische Berichte/Recueil'' in 1997. ''Chemische Berichte/Recueil'' was then merged with other European journals in 1998 to form ''European Journal of Inorganic Chemistry''. History Founded in 1868 as ''Berichte der Deutschen Chemischen Gesellschaft'' (, CODEN BDCGAS), it operated under this title until 1928 (Vol. 61). The journal was then split into: * ''Berichte der Deutschen Chemischen Gesellschaft, A: Vereins-Nachrichten'' (, CODEN BDCAAS), and * ''Berichte der Deutschen Chemischen Gesellschaft, B: Abhandlungen'' (, CODEN BDCBAD). Vol. 78 and 79 (1945–1946) were omitted and not published due to World War II. The journal was renamed ''Chemische Berichte'' (, CODEN CHBEAM) in 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barton–McCombie Deoxygenation
The Barton–McCombie deoxygenation is an organic reaction in which a hydroxy functional group in an organic compound is replaced by a hydrogen to give an alkyl group. It is named after British chemists Sir Derek Harold Richard Barton and Stuart W. McCombie. This deoxygenation reaction is a radical substitution. In the related Barton decarboxylation the reactant is a carboxylic acid. Mechanism The reaction mechanism consists of a catalytic radical initiation step and a propagation step. The alcohol (1) is first converted into a reactive carbonothioyl intermediate such as a thionoester or xanthate 2. Heating of AIBN results in its homolytic cleavage, generating two 2-cyanoprop-2-yl radicals 9 which each abstract a proton from tributylstannane 3 to generate tributylstannyl radicals 4 and inactive 10. The tributyltin radical abstracts the xanthate group from 2 by attack of 4 at the sulfur atom with concurrent homolytic cleavage of the C-S π bond. This leaves a carbon centered ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ester Pyrolysis
Ester pyrolysis in organic chemistry is a vacuum pyrolysis reaction converting esters containing a β-hydrogen atom into the corresponding carboxylic acid and the alkene. The reaction is an Ei elimination, Ei elimination and operates in a syn fashion. Examples include the synthesis of acrylic acid from ethyl acrylate at 590 °C, the synthesis of 1,4-pentadiene from 1,5-pentanediol diacetate at 575 °C or the construction of a cyclobutene framework at 700 °C Organic Syntheses, Coll. Vol. 5, p.235 (1973); Vol. 43, p.17 (1963)Link/ref> : References {{reflist Organic reactions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cope Elimination
The Cope reaction or Cope elimination, developed by Arthur C. Cope, is an elimination reaction of the N-oxide to form an alkene and a hydroxylamine. Mechanism and applications The reaction mechanism involves an intramolecular 5-membered cyclic transition state, leading to a ''syn'' elimination product, an Ei pathway. This organic reaction is closely related to the Hofmann elimination, but the base is a part of the leaving group. The amine oxide is prepared by oxidation of the corresponding amine with an oxidant such as meta-chloroperoxybenzoic acid (''m''CPBA). The actual elimination just requires heat. : Illustrative of the Cope reaction is a synthesis of methylenecyclohexane: : Piperidines are resistant to an intramolecular Cope reaction but with pyrrolidine and with rings of size 7 and larger, the reaction product is an unsaturated hydroxyl amine. This result is consistent with the 5-membered cyclic transition state. : Reverse reaction The reverse or retro-Cope elimi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methanethiol
Methanethiol (also known as methyl mercaptan) is an organosulfur compound with the chemical formula . It is a colorless gas with a distinctive putrid smell. It is a natural substance found in the blood, brain and feces of animals (including humans), as well as in plant tissues. It also occurs naturally in certain foods, such as some nuts and cheese. It is one of the chemical compounds responsible for bad breath and the smell of flatus. Methanethiol is the simplest thiol and is sometimes abbreviated as MeSH. It is very flammable. Structure and reactions The molecule is tetrahedral at the carbon atom, like methanol. It is a weak acid, with a p''K''a of ~10.4, but is about a hundred thousand times more acidic than methanol. The colorless salt can be obtained in this way: :CH3SH + CH3ONa → CH3SNa + CH3OH The resulting thiolate anion is a strong nucleophile. It can be oxidized to dimethyl disulfide: :2CH3SH + → CH3SSCH3 + H2O Further oxidation takes the disulfide to two mol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ei Mechanism
In organic chemistry, the Ei mechanism (Elimination Internal/Intramolecular), also known as a thermal syn elimination or a pericyclic syn elimination, is a special type of elimination reaction in which two Vicinal (chemistry), vicinal (adjacent) substituents on an alkane framework leave simultaneously via a cyclic transition state to form an alkene in a syn elimination, ''syn'' elimination. This type of elimination is unique because it is thermally activated and does not require additional reagents, unlike regular eliminations, which require an acid or Base (chemistry), base, or would in many cases involve charged Reaction intermediate, intermediates. This reaction mechanism is often found in pyrolysis. General features Compounds that undergo elimination through cyclic transition states upon heating, with no other reagents present, are given the designation as Ei reactions. Depending on the compound, elimination takes place through a four, five, or six-membered transition state.Ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alcohol (chemistry)
In chemistry, an alcohol is a type of organic compound that carries at least one hydroxyl () functional group bound to a saturated carbon atom. The term ''alcohol'' originally referred to the primary alcohol ethanol (ethyl alcohol), which is used as a drug and is the main alcohol present in alcoholic drinks. An important class of alcohols, of which methanol and ethanol are the simplest examples, includes all compounds which conform to the general formula . Simple monoalcohols that are the subject of this article include primary (), secondary () and tertiary () alcohols. The suffix ''-ol'' appears in the IUPAC chemical name of all substances where the hydroxyl group is the functional group with the highest priority. When a higher priority group is present in the compound, the prefix ''hydroxy-'' is used in its IUPAC name. The suffix ''-ol'' in non-IUPAC names (such as paracetamol or cholesterol) also typically indicates that the substance is an alcohol. However, some compou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chugaev2
Lev Aleksandrovich Chugaev (16 October 1873 – 26 September 1922) was a Russian chemist. At the height of his career, he was professor of chemistry at the University of Petersburg, being the successor to Dmitri Mendeleev. He was active in the fields of inorganic chemistry, especially platinum group complexes, as well as organic chemistry. He is also known as Leo Aleksandrovich Tschugaeff or Tschugaev. Contributions to coordination chemistry Chugaev discovered that dimethylglyoxime forms a scarlet solid upon reaction with nickel(II) ions. This reaction was one of the first "spot tests" for a metal ion. An adherent to the theories of Alfred Werner, Chugaev made several contributions to the chemistry of platinum. The salt t(NH3)5Cll3 containing the chloropentammineplatinum(IV) ion, is called "Chugaev's salt". Other complexes prepared in his laboratory include Diethyl_sulfide.html" ;"title="t(Diethyl sulfide">SEt2)4PtCl4], [Pt(NH3)5OH]Cl3, [Os(thiourea, SC(NH2)2)6]Cl3.H2O. C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
