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Bouveault–Blanc Reduction
The Bouveault–Blanc reduction is a chemical reaction in which an ester is reduced to primary alcohols using absolute ethanol and sodium metal. It was first reported by Louis Bouveault and Gustave Louis Blanc in 1903. Bouveault and Blanc demonstrated the reduction of ethyl oleate and ''n''-butyl oleate to oleyl alcohol. modified versions of which were subsequently refined and published in ''Organic Syntheses''. : This reaction is used commercially although for laboratory scale reactions it was made obsolete by the introduction of lithium aluminium hydride. Reaction mechanism Sodium metal is a one-electron reducing agent. Four equivalents of sodium are required to fully reduce each ester. Ethanol serves as a proton source. The reaction produces sodium alkoxides, according to the following stoichiometry: : + 6 Na + 4 → + + 4 In practice, considerable sodium is consumed by the formation of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Louis Bouveault
Louis Bouveault (11 February 1864 – 5 September 1909) was a French scientist who became professor of organic chemistry at the Faculty of Sciences of the University of Paris. He is known for the Bouveault aldehyde synthesis and the Bouveault–Blanc reduction. Life Louis Bouveault was born on 11 February 1864 in Nevers. He obtained doctorates in Paris in medicine and physical sciences. Bouveault defended his thesis on β-keto nitriles and their derivatives in Paris in 1890. He taught for a short period at the Medical Faculty in Lyon, then became a lecturer in general chemistry in Lyon. He influenced Victor Grignard to take up chemistry in 1894. In Lyon he investigated syntheses with camphor and terpenes. He worked with Philippe Barbier on terpene derivatives used in the manufacture of perfumes like citral, rhodinal and geraniol. Bouveault moved on from Lyon to Lille, Nancy and finally to Paris. He was appointed professor of organic chemistry at the Faculty of Sciences of the U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lithium Aluminium Hydride
Lithium aluminium hydride, commonly abbreviated to LAH, is an inorganic compound with the chemical formula Li Al H4. It is a white solid, discovered by Finholt, Bond and Schlesinger in 1947. This compound is used as a reducing agent in organic synthesis, especially for the reduction of esters, carboxylic acids, and amides. The solid is dangerously reactive toward water, releasing gaseous hydrogen (H2). Some related derivatives have been discussed for hydrogen storage. Properties, structure, preparation LAH is a colourless solid but commercial samples are usually gray due to contamination. This material can be purified by recrystallization from diethyl ether. Large-scale purifications employ a Soxhlet extractor. Commonly, the impure gray material is used in synthesis, since the impurities are innocuous and can be easily separated from the organic products. The pure powdered material is pyrophoric, but not its large crystals. Some commercial materials contain mineral oil to in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Free Radical Reactions
Free may refer to: Concept * Freedom, having the ability to do something, without having to obey anyone/anything * Freethought, a position that beliefs should be formed only on the basis of logic, reason, and empiricism * Emancipate, to procure political rights, as for a disenfranchised group * Free will, control exercised by rational agents over their actions and decisions * Free of charge, also known as gratis. See Gratis vs libre. Computing * Free (programming), a function that releases dynamically allocated memory for reuse * Free format, a file format which can be used without restrictions * Free software, software usable and distributable with few restrictions and no payment * Freeware, a broader class of software available at no cost Mathematics * Free object ** Free abelian group ** Free algebra ** Free group ** Free module ** Free semigroup * Free variable People * Free (surname) * Free (rapper) (born 1968), or Free Marie, American rapper and media personality ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bouveault Aldehyde Synthesis
The Bouveault aldehyde synthesis (also known as the Bouveault reaction) is a one-pot substitution reaction that replaces an alkyl or aryl halide with a formyl group using a ''N'',''N''-disubstituted formamide. For primary alkyl halides this produces the homologous aldehyde one carbon longer. For aryl halides this produces the corresponding carbaldehyde. The Bouveault aldehyde synthesis is an example of a formylation reaction, and is named for French scientist Louis Bouveault. : Reaction mechanism The first step of the Bouveault aldehyde synthesis is the formation of the Grignard reagent. Upon addition of a ''N'',''N''-disubstituted formamide (such as dimethylformamide) a hemiaminal is formed, which can easily be hydrolyzed into the desired aldehyde. Variations Variants using organolithium reagents instead of magnesium-based Grignard reagents are also considered Bouveault aldehyde syntheses.Jie Jack Li. ''Name Reactions: A Collection of Detailed Reaction Mechanisms''. Springer, 200 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Birch Reduction
The Birch reduction is an organic reaction that is used to convert arenes to cyclohexadienes. The reaction is named after the Australian chemist Arthur Birch and involves the organic reduction of aromatic rings in an amine solvent (traditionally liquid ammonia) with an alkali metal (traditionally sodium) and a proton source (traditionally an alcohol). Unlike catalytic hydrogenation, Birch reduction does not reduce the aromatic ring all the way to a cyclohexane. An example is the reduction of naphthalene in ammonia and ethanol: Reaction mechanism and regioselectivity A solution of sodium in liquid ammonia consists of the intensely blue electride salt a(NH3)xsup>+ e−. The solvated electrons add to the aromatic ring to give a radical anion, which then abstracts a proton from the alcohol. The process then repeats at either the ''ortho'' or ''para'' position (depending on substituents) to give the final diene. The residual double bonds do not stabilize further radical add ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Akabori Amino-acid Reaction
There are several Akabori amino acid reactions, which are named after Shirō Akabori (1900–1992), a Japanese chemist. In the first reaction, an α-amino acid is oxidised and undergoes decarboxylation to give an aldehyde at the former α position by heating with oxygen in the presence of a reducing sugar. This reaction is useful for preparing dichlorophthalimido derivatives of peptides for mass spectral analysis. : In the second reaction, an α-amino acid, or an ester of it, is reduced by sodium amalgam and ethanolic HCl to give an α-amino aldehyde. This process is conceptually similar to the Bouveault–Blanc reduction except that it stops at the aldehyde stage rather than reducing the ester all the way to two alcohols. : See also *Maillard reaction The Maillard reaction ( ; ) is a chemical reaction between amino acids and reducing sugars that gives browned food its distinctive flavor. Seared steaks, fried dumplings, cookies and other kinds of biscuits, breads, toasted ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acyloin Condensation
Acyloin condensation is a reductive coupling of two carboxylic esters using metallic sodium to yield an α-hydroxyketone, also known as an acyloin. The reaction is most successful when ''R'' is aliphatic and saturated. The reaction is performed in aprotic solvents with a high boiling point, such as benzene and toluene in an oxygen free atmosphere of nitrogen (as even traces of oxygen interfere with the reaction path and reduce the yield). The use of protic solvents results in the Bouveault-Blanc reduction of the separate esters rather than condensation. Depending on ring size and steric properties, but independent from high dilution, the acyloin condensation of diesters favours intramolecular cyclisation over intermolecular polymerisation when diesters are used (see below). To account for such cyclisation, it is suggested that the ends, where ester groups are present, are adsorbed, albeit weakly, at nearby sites on the sodium metal. Thus, the reactive ends are not available f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silica Gel
Silica gel is an amorphous and porous form of silicon dioxide (silica), consisting of an irregular tridimensional framework of alternating silicon and oxygen atoms with nanometer-scale voids and pores. The voids may contain water or some other liquids, or may be filled by gas or vacuum. In the last case, the material is properly called silica xerogel. Silica xerogel with an average pore size of 2.4 nanometers has a strong affinity for water molecules and is widely used as a desiccant. It is hard and translucent, but considerably softer than massive silica glass or quartz; and remains hard when saturated with water. Silica xerogel is usually commercialized as coarse granules or beads, a few millimeters in diameter. Some grains may contain small amounts of indicator substance that changes color when they have absorbed some water. Small paper envelopes containing silica xerogel pellets, usually with a "do not eat" warning, are often included in dry food packages to absorb any h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
M-SG Reducing Agent
In M-SG an alkali metal is absorbed into silica gel at elevated temperatures. The resulting black powder material is an effective reducing agent and safe to handle as opposed to the pure metal. The material can also be used as a desiccant and as a hydrogen source.''Alkali Metals Plus Silica Gel: Powerful Reducing Agents and Convenient Hydrogen Sources '' James L. Dye, Kevin D. Cram, Stephanie A. Urbin, Mikhail Y. Redko, James E. Jackson, and Michael Lefenfeld J. Am. Chem. Soc., 127 (26), 9338 -9339, 2005''Abstract/ref> The metal is either sodium or a sodium - potassium alloy ( Na2K). The molten metal is mixed with silica gel under constant agitation at room temperature. This phase 0 material must be handled in an inert atmosphere. Heating phase 0 at takes it to phase I. When this material is exposed to dry oxygen the reducing power is not affected. At further heating to phase II can be handled safely in an ambient environment. The metal reacts with the silica gel in an exother ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkoxides
In chemistry, an alkoxide is the conjugate base of an alcohol and therefore consists of an organic group bonded to a negatively charged oxygen atom. They are written as , where R is the organic substituent. Alkoxides are strong bases and, when R is not bulky, good nucleophiles and good ligands. Alkoxides, although generally not stable in protic solvents such as water, occur widely as intermediates in various reactions, including the Williamson ether synthesis. Transition metal alkoxides are widely used for coatings and as catalysts. Enolates are unsaturated alkoxides derived by deprotonation of a bond adjacent to a ketone or aldehyde. The nucleophilic center for simple alkoxides is located on the oxygen, whereas the nucleophilic site on enolates is delocalized onto both carbon and oxygen sites. Ynolates are also unsaturated alkoxides derived from acetylenic alcohols. Phenoxides are close relatives of the alkoxides, in which the alkyl group is replaced by a derivative o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethanol
Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an Alcohol (chemistry), alcohol with the chemical formula . Its formula can be also written as or (an ethyl group linked to a hydroxyl group). Ethanol is a Volatility (chemistry), volatile, Combustibility and flammability, flammable, colorless liquid with a characteristic wine-like odor and pungent taste. It is a psychoactive recreational drug, the active ingredient in alcoholic drinks. Ethanol is naturally produced by the fermentation process of Carbohydrate, sugars by yeasts or via Petrochemistry, petrochemical processes such as ethylene hydration. It has medical applications as an antiseptic and disinfectant. It is used as a chemical solvent and in the Chemical synthesis, synthesis of organic compounds, and as a Alcohol fuel, fuel source. Ethanol also can be dehydrated to make ethylene, an important chemical feedstock. As of 2006, world produ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
