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Eglinton Coupling
The Glaser coupling is a type of coupling reaction. It is by far the oldest acetylenic coupling and is based on cuprous salts like copper(I) chloride or copper(I) bromide and an additional oxidant like oxygen. The base in its original scope is ammonia. The solvent is water or an alcohol. The reaction was first reported by in 1869. He suggested the following process for his way to diphenylbutadiyne: :CuCl + PhC2H + NH3 → PhC2Cu + NH4Cl :2PhC2Cu + O → PhC2C2Ph + Cu2O Modifications Eglinton reaction In the related Eglinton reaction two terminal alkynes are coupled by a copper(II) salt such as cupric acetate. :2R-\!\!-H -> ce\ce] R-\!\!-\!\!-R The oxidative coupling of alkynes has been used to synthesize a number of fungal antibiotics. The stoichiometry is represented by this highly simplified scheme: : Such reactions proceed via metal-alkyne complex, copper(I)-alkyne complexes. This methodology was used in the synthesis of cyclooctadecanonaene. Another example is the synthe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coupling Reaction
A coupling reaction in organic chemistry is a general term for a variety of reactions where two fragments are joined together with the aid of a metal catalyst. In one important reaction type, a main group organometallic compound of the type R-M (R = organic fragment, M = main group center) reacts with an organic halide of the type R'-X with formation of a new carbon-carbon bond in the product R-R'. The most common type of coupling reaction is the cross coupling reaction. Richard F. Heck, Ei-ichi Negishi, and Akira Suzuki were awarded the 2010 Nobel Prize in Chemistry for developing palladium-catalyzed cross coupling reactions. Broadly speaking, two types of coupling reactions are recognized: *Heterocouplings combine two different partners, such as in the Heck reaction of an alkene (RC=CH) and an alkyl halide (R'-X) to give a substituted alkene, or the Corey–House synthesis of an alkane by the reaction of a lithium diorganylcuprate (R2CuLi) with an organyl (pseudo)halide (R'X ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trimethylsilylacetylene
Trimethylsilylacetylene is the organosilicon compound with the formula . A colorless liquid, "tms acetylene", as it is also called, is used as a source of "HC2−" in organic synthesis. Use Trimethylsilylacetylene is used in Sonogashira couplings as the equivalent of acetylene. Using this protected alkyne, as opposed to acetylene itself, prevents further coupling reactions. The trimethylsilyl group can then be cleaved off with TBAF or DBU, either separately or as part of a one-pot Sonogashira reaction to form phenylacetylene derivatives. A less expensive alternative reagent is 2-methylbut-3-yn-2-ol, which after alkynylation is deprotected with base. Trimethylsilylacetylene is commercially available. It may also be prepared in a manner similar to other silyl compounds: deprotonation of acetylene with a Grignard reagent, followed by reaction with trimethylsilyl chloride. Trimethylsilylacetylene is a precursor to 1,4-bis(trimethylsilyl)buta-1,3-diyne, a protected form of 1,3-buta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copper(I) Acetylide
Copper(I) acetylide, or cuprous acetylide, is a chemical compound with the formula copper, Cu2carbon, C2. Although never characterized by X-ray crystallography, the material has been claimed at least since 1856. One form is claimed to be a monohydrate with formula .. It is a reddish solid, that easily explodes when dry. Synthesis Materials purported to be copper acetylide can be prepared by treating acetylene with a solution of copper(I) chloride and ammonia: :C2H2 (g) + 2 CuCl (s) → Cu2C2 (s) + 2 HCl (g) This reaction produces a reddish solid precipitate. Properties When dry, copper acetylide is a heat and shock sensitive high explosive, more thermally sensitive than silver acetylide. Copper acetylide is thought to form inside pipes made of copper or an alloy with high copper content, which may result in violent explosion. This was found to be the cause of explosions in acetylene plants, and led to abandonment of copper as a construction material in such plants. Copper c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sonogashira Coupling
The Sonogashira reaction is a cross-coupling reaction used in organic synthesis to form carbon–carbon bonds. It employs a palladium catalyst as well as copper co-catalyst to form a carbon–carbon bond between a terminal alkyne and an aryl or vinyl halide. :* : aryl or vinyl :* : arbitrary :* X: I, Br, Cl or OTf The Sonogashira cross-coupling reaction has been employed in a wide variety of areas, due to its usefulness in the formation of carbon–carbon bonds. The reaction can be carried out under mild conditions, such as at room temperature, in aqueous media, and with a mild base, which has allowed for the use of the Sonogashira cross-coupling reaction in the synthesis of complex molecules. Its applications include pharmaceuticals, natural products, organic materials, and nanomaterials. Specific examples include its use in the synthesis of tazarotene, which is a treatment for psoriasis and acne, and in the preparation of SIB-1508Y, also known as Altinicline, a nicotinic recep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cadiot–Chodkiewicz Coupling
The Cadiot–Chodkiewicz coupling in organic chemistry is a coupling reaction between a terminal alkyne and a haloalkyne catalyzed by a copper(I) salt such as copper(I) bromide and an amine base.Cadiot, P.; Chodkiewicz, W. In Chemistry of Acetylenes; Viehe, H. G., Ed.; Marcel Dekker: New York, 1969; pp. 597–647. The reaction product is a 1,3-diyne or di-alkyne. The reaction mechanism involves deprotonation by base of the terminal alkyne proton followed by formation of a copper(I) acetylide. A cycle of oxidative addition and reductive elimination on the copper centre then creates a new carbon-carbon bond. Scope Unlike the related Glaser coupling the Cadiot–Chodkiewicz coupling proceeds selectively and will only couple the alkyne to the haloalkyne, giving a single product. By comparison the Glaser coupling would simply produce a distribution of all possible couplings. In one study the Cadiot–Chodkiewicz coupling has been applied in the synthesis of acetylene macrocycles st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baeyer–Drewson Indigo Synthesis
The Baeyer–Drewson indigo synthesis (1882) is an organic reaction in which indigo is prepared from 2-nitrobenzaldehyde and acetone The reaction was developed by von Baeyer in 1880 to produce the first synthetic indigo at laboratory scale. This procedure is not used at industrial scale. The reaction is classified as an aldol condensation. As a practical route to indigo, this method was displaced by routes from aniline Aniline is an organic compound with the formula C6 H5 NH2. Consisting of a phenyl group attached to an amino group, aniline is the simplest aromatic amine In organic chemistry, an aromatic amine is an organic compound consisting of an aroma ....Elmar Steingruber "Indigo and Indigo Colorants" Ullmann's Encyclopedia of Industrial Chemistry 2004, Wiley-VCH, Weinheim. Mechanism Note In the English literature this reaction is usually called Baeyer–Drewson reaction, although the author of the original paper was called Drewsen. References E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baeyer Indigo Synthesis
Johann Friedrich Wilhelm Adolf von Baeyer (; 31 October 1835 – 20 August 1917) was a German chemist who synthesised indigo and developed a nomenclature for cyclic compounds (that was subsequently extended and adopted as part of the IUPAC organic nomenclature). He was ennobled in the Kingdom of Bavaria in 1885 and was the 1905 recipient of the Nobel Prize in Chemistry.''Adolf von Baeyer: Winner of the Nobel Prize for Chemistry 1905 '' Armin de Meijere Angewandte Chemie International Edition Volume 44, Issue 48, Pages 7836 – 7840 2005''Abstract/ref> Family and education Baeyer was born in Berlin as the son of the noted geodesist and captain of the Royal Prussian Army Johann Jacob Baeyer and his wife Eugenie Baeyer née Hitzig (1807–1843). Both his parents were Lutherans at the time of his birth and he was raised in the Lutheran religion. His mother was the daughter of Julius Eduard Hitzig and a member of the originally Jewish Itzig family, and had converted to Christianity ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indigo Dye
Indigo dye is an organic compound with a distinctive blue color. Historically, indigo was a natural dye extracted from the leaves of some plants of the ''Indigofera'' genus, in particular ''Indigofera tinctoria''; dye-bearing ''Indigofera'' plants were commonly grown and used throughout the world, in Asia in particular, as an important crop, with the production of indigo dyestuff economically important due to the previous rarity of some blue dyestuffs historically. Most indigo dye produced today is synthetic, constituting several thousand tons each year. It is most commonly associated with the production of denim cloth and blue jeans, where its properties allow for effects such as stone washing and acid washing to be applied quickly. Uses The primary use for indigo is as a dye for cotton yarn, mainly used in the production of denim cloth suitable for blue jeans; on average, a pair of blue jeans requires just to of dye. Smaller quantities are used in the dyeing of wool and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adolf Von Baeyer
Johann Friedrich Wilhelm Adolf von Baeyer (; 31 October 1835 – 20 August 1917) was a German chemist who synthesised indigo and developed a nomenclature for cyclic compounds (that was subsequently extended and adopted as part of the IUPAC organic nomenclature). He was ennobled in the Kingdom of Bavaria in 1885 and was the 1905 recipient of the Nobel Prize in Chemistry.''Adolf von Baeyer: Winner of the Nobel Prize for Chemistry 1905 '' Armin de Meijere Angewandte Chemie International Edition Volume 44, Issue 48, Pages 7836 – 7840 2005''Abstract/ref> Family and education Baeyer was born in Berlin as the son of the noted geodesist and captain of the Royal Prussian Army Johann Jacob Baeyer and his wife Eugenie Baeyer née Hitzig (1807–1843). Both his parents were Lutherans at the time of his birth and he was raised in the Lutheran religion. His mother was the daughter of Julius Eduard Hitzig and a member of the originally Jewish Itzig family, and had converted to Christianity ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TMEDA
Tetramethylethylenediamine (TMEDA or TEMED) is a chemical compound with the formula (CH3)2NCH2CH2N(CH3)2. This species is derived from ethylenediamine by replacement of the four amine hydrogens with four methyl groups. It is a colorless liquid, although old samples often appear yellow. Its odor is similar to that of rotting fish. As a reagent in synthesis TMEDA is widely employed as a ligand for metal ions. It forms stable complexes with many metal halides, e.g. zinc chloride and copper(I) iodide, giving complexes that are soluble in organic solvents. In such complexes, TMEDA serves as a bidentate ligand. TMEDA has an affinity for lithium ions. When mixed with ''n''-butyllithium, TMEDA's nitrogen atoms coordinate to the lithium, forming a cluster of higher reactivity than the tetramer or hexamer that ''n''-butyllithium normally adopts. BuLi/TMEDA is able to metallate or even doubly metallate many substrates including benzene, furan, thiophene, ''N''-alkylpyrroles, and ferrocene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copper(I) Chloride
Copper(I) chloride, commonly called cuprous chloride, is the lower chloride of copper, with the formula CuCl. The substance is a white solid sparingly soluble in water, but very soluble in concentrated hydrochloric acid. Impure samples appear green due to the presence of copper(II) chloride (CuCl2). History Copper(I) chloride was first prepared by Robert Boyle in the mid-seventeenth century from mercury(II) chloride ("Venetian sublimate") and copper metal: :HgCl2 + 2 Cu → 2 CuCl + Hg In 1799, J.L. Proust characterized the two different chlorides of copper. He prepared CuCl by heating CuCl2 at red heat in the absence of air, causing it to lose half of its combined chlorine followed by removing residual CuCl2 by washing with water. An acidic solution of CuCl was formerly used for analysis of carbon monoxide content in gases, for example in Hempel's gas apparatus. This application was significant during the nineteenth and early twentieth centuries when coal gas was widely ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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