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Cyanation
In organic synthesis, cyanation is the attachment or substitution of a cyanide group on various substrates. Such transformations are high-value because they generate C-C bond. Furthermore nitriles are versatile functional groups. Cyanation to form sp3 nitriles Typically, alkyl nitriles are formed ''via'' SN1 or SN2-type cyanation with alkyl electrophiles. Illustrative is the synthesis of benzyl cyanide by the reaction of benzyl chloride and sodium cyanide. In some cases cuprous cyanide is used instead of sodium cyanide. Cyanation of ketones or aldehydes yields the corresponding cyanohydrins, which can be done directly with the cyanide ion (the cyanohydrin reaction) or by using bisulfite, followed by displacement of sulfite: A related reaction is hydrocyanation, which installs the elements of H-CN. Cyanation of arenes Cyanation of arenes offers access to benzoic acid derivatives, as well as the utility of aryl nitriles themselves in as fine chemicals: A variety of mechani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyanation Of Aldehyde With Bisulfate
In organic synthesis, cyanation is the attachment or substitution of a cyanide group on various substrates. Such transformations are high-value because they generate C-C bond. Furthermore nitriles are versatile functional groups. Cyanation to form sp3 nitriles Typically, alkyl nitriles are formed ''via'' SN1 or SN2-type cyanation with alkyl electrophiles. Illustrative is the synthesis of benzyl cyanide by the reaction of benzyl chloride and sodium cyanide. In some cases cuprous cyanide is used instead of sodium cyanide. Cyanation of ketones or aldehydes yields the corresponding cyanohydrins, which can be done directly with the cyanide ion (the cyanohydrin reaction) or by using bisulfite, followed by displacement of sulfite: A related reaction is hydrocyanation, which installs the elements of H-CN. Cyanation of arenes Cyanation of arenes offers access to benzoic acid derivatives, as well as the utility of aryl nitriles themselves in as fine chemicals: A variety of mechanisti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyanation Starburst
In organic synthesis, cyanation is the attachment or substitution of a cyanide group on various substrates. Such transformations are high-value because they generate C-C bond. Furthermore nitriles are versatile functional groups. Cyanation to form sp3 nitriles Typically, alkyl nitriles are formed ''via'' SN1 or SN2-type cyanation with alkyl electrophiles. Illustrative is the synthesis of benzyl cyanide by the reaction of benzyl chloride and sodium cyanide. In some cases cuprous cyanide is used instead of sodium cyanide. Cyanation of ketones or aldehydes yields the corresponding cyanohydrins, which can be done directly with the cyanide ion (the cyanohydrin reaction) or by using bisulfite, followed by displacement of sulfite: A related reaction is hydrocyanation, which installs the elements of H-CN. Cyanation of arenes Cyanation of arenes offers access to benzoic acid derivatives, as well as the utility of aryl nitriles themselves in as fine chemicals: A variety of mechani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sandmeyer Reaction
The Sandmeyer reaction is a chemical reaction used to synthesize aryl halides from aryl diazonium salts using copper salts as reagents or catalysts. It is an example of a radical-nucleophilic aromatic substitution. The Sandmeyer reaction provides a method through which one can perform unique transformations on benzene, such as halogenation, cyanation, trifluoromethylation, and hydroxylation. : The reaction was discovered in 1884 by Swiss chemist Traugott Sandmeyer, when he attempted to synthesize phenylacetylene from benzenediazonium chloride and copper(I) acetylide. Instead, the main product he isolated was chlorobenzene. In modern times, the Sandmeyer reaction refers to any method for substitution of an aromatic amino group via preparation of its diazonium salt followed by its displacement with a nucleophile in the presence of catalytic copper(I) salts. (Due to the low cost of copper salts, a stoichiometric amount is often employed for better reactivity even when catalysis is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cuprous Cyanide
Copper(I) cyanide is an inorganic compound with the formula CuCN. This off-white solid occurs in two Polymorphism (materials science), polymorphs; impure samples can be green due to the presence of Cu(II) impurities. The compound is useful as a catalyst, in electroplating copper, and as a reagent in the preparation of nitriles.H. Wayne Richardson "Copper Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005. Structure Copper cyanide is a coordination polymer. It exists in two polymorphs both of which contain -[Cu-CN]- chains made from linear copper(I) centres linked by cyanide bridging ligand, bridges. In the high-temperature polymorph, HT-CuCN, which is isostructural with silver cyanide, AgCN, the linear chains pack on a hexagonal lattice and adjacent chains are off set by +/- 1/3 ''c'', Figure 1. In the low-temperature polymorph, LT-CuCN, the chains deviate from linearity and pack into rippled layers which pack in an AB fashion with chains in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyanohydrin
In organic chemistry, a cyanohydrin or hydroxynitrile is a functional group found in organic compounds in which a cyano and a hydroxy group are attached to the same carbon atom. The general formula is , where R is H, alkyl, or aryl. Cyanohydrins are industrially important precursors to carboxylic acids and some amino acids. Cyanohydrins can be formed by the cyanohydrin reaction, which involves treating a ketone or an aldehyde with hydrogen cyanide (HCN) in the presence of excess amounts of sodium cyanide (NaCN) as a catalyst: : In this reaction, the nucleophilic ion attacks the electrophilic carbonyl carbon in the ketone, followed by protonation by HCN, thereby regenerating the cyanide anion. Cyanohydrins are also prepared by displacement of sulfite by cyanide salts: : Cyanohydrins are intermediates in the Strecker amino acid synthesis. In aqueous acid, they are hydrolyzed to the α-hydroxy acid. Acetone cyanohydrins Acetone cyanohydrin, (CH3)2C(OH)CN is the cyano ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copper(I) Cyanide
Copper(I) cyanide is an inorganic compound with the formula CuCN. This off-white solid occurs in two polymorphs; impure samples can be green due to the presence of Cu(II) impurities. The compound is useful as a catalyst, in electroplating copper, and as a reagent in the preparation of nitriles.H. Wayne Richardson "Copper Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005. Structure Copper cyanide is a coordination polymer. It exists in two polymorphs both of which contain - u-CN chains made from linear copper(I) centres linked by cyanide bridges. In the high-temperature polymorph, HT-CuCN, which is isostructural with AgCN, the linear chains pack on a hexagonal lattice and adjacent chains are off set by +/- 1/3 ''c'', Figure 1. In the low-temperature polymorph, LT-CuCN, the chains deviate from linearity and pack into rippled layers which pack in an AB fashion with chains in adjacent layers rotated by 49 °, Figure 2. File:Structure of HT-C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyanide
Cyanide is a naturally occurring, rapidly acting, toxic chemical that can exist in many different forms. In chemistry, a cyanide () is a chemical compound that contains a functional group. This group, known as the cyano group, consists of a carbon atom triple-bonded to a nitrogen atom. In inorganic cyanides, the cyanide group is present as the anion . Soluble salts such as sodium cyanide (NaCN) and potassium cyanide (KCN) are highly toxic. Hydrocyanic acid, also known as hydrogen cyanide, or HCN, is a highly volatile liquid that is produced on a large scale industrially. It is obtained by acidification of cyanide salts. Organic cyanides are usually called nitriles. In nitriles, the group is linked by a covalent bond to carbon. For example, in acetonitrile (), the cyanide group is bonded to methyl (). Although nitriles generally do not release cyanide ions, the cyanohydrins do and are thus rather toxic. Bonding The cyanide ion is isoelectronic with carbon monoxide a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zinc Cyanide
Zinc cyanide is the inorganic compound with the formula Zn( CN)2. It is a white solid that is used mainly for electroplating zinc but also has more specialized applications for the synthesis of organic compounds. Structure In Zn(CN)2, zinc adopts the tetrahedral coordination environment, all linked by bridging cyanide ligands. The structure consists of two "interpenetrating" structures (blue and red in the picture above). Such motifs are sometimes called "expanded diamondoid" structures. Some forms of SiO2 adopt a similar structure, wherein the tetrahedral Si centres are linked by oxides. The cyanide group shows head to tail disorder with any zinc atom having between one and four carbon neighbours, and the remaining being nitrogen atoms. It shows one of the largest negative coefficients of thermal expansion (exceeding the previous record holder, zirconium tungstate). Chemical properties Typical for an inorganic polymer, Zn(CN)2 is insoluble in most solvents. The solid disso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleophile
In chemistry, a nucleophile is a chemical species that forms bonds by donating an electron pair. All molecules and ions with a free pair of electrons or at least one pi bond can act as nucleophiles. Because nucleophiles donate electrons, they are Lewis bases. ''Nucleophilic'' describes the affinity of a nucleophile to bond with positively charged atomic nuclei. Nucleophilicity, sometimes referred to as nucleophile strength, refers to a substance's nucleophilic character and is often used to compare the affinity of atoms. Neutral nucleophilic reactions with solvents such as alcohols and water are named solvolysis. Nucleophiles may take part in nucleophilic substitution, whereby a nucleophile becomes attracted to a full or partial positive charge, and nucleophilic addition. Nucleophilicity is closely related to basicity. History The terms ''nucleophile'' and ''electrophile'' were introduced by Christopher Kelk Ingold in 1933, replacing the terms ''anionoid'' and ''cationoid' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toxicity
Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a substructure of the organism, such as a cell ( cytotoxicity) or an organ such as the liver (hepatotoxicity). By extension, the word may be metaphorically used to describe toxic effects on larger and more complex groups, such as the family unit or society at large. Sometimes the word is more or less synonymous with poisoning in everyday usage. A central concept of toxicology is that the effects of a toxicant are dose-dependent; even water can lead to water intoxication when taken in too high a dose, whereas for even a very toxic substance such as snake venom there is a dose below which there is no detectable toxic effect. Toxicity is species-specific, making cross-species analysis problematic. Newer paradigms and metrics are evolving to bypas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potassium Ferricyanide
Potassium ferricyanide is the chemical compound with the formula K3 e(CN)6 This bright red salt contains the octahedrally coordinated 3−.html" ;"title="e(CN)6sup>3−">e(CN)6sup>3− ion. It is soluble in water and its solution shows some green-yellow fluorescence. It was discovered in 1822 by Leopold Gmelin. Preparation Potassium ferricyanide is manufactured by passing chlorine through a solution of potassium ferrocyanide. Potassium ferricyanide separates from the solution: :2 K4 e(CN)6+ Cl2 → 2 K3 e(CN)6+ 2 KCl Structure Like other metal cyanides, solid potassium ferricyanide has a complicated polymeric structure. The polymer consists of octahedral e(CN)6sup>3− centers crosslinked with K+ ions that are bound to the CN ligands. The K+---NCFe linkages break when the solid is dissolved in water. Applications The compound is also used to harden iron and steel, in electroplating, dyeing wool, as a laboratory reagent, and as a mild oxidizing agent in organic chemist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reductive Elimination
Reductive elimination is an elementary step in organometallic chemistry in which the oxidation state of the metal center decreases while forming a new covalent bond between two ligands. It is the microscopic reverse of oxidative addition, and is often the product-forming step in many catalytic processes. Since oxidative addition and reductive elimination are reverse reactions, the same mechanisms apply for both processes, and the product equilibrium depends on the thermodynamics of both directions. General information Reductive elimination is often seen in higher oxidation states, and can involve a two-electron change at a single metal center (mononuclear) or a one-electron change at each of two metal centers (binuclear, dinuclear, or bimetallic). For mononuclear reductive elimination, the oxidation state of the metal decreases by two, while the d-electron count of the metal increases by two. This pathway is common for d8 metals Ni(II), Pd(II), and Au(III) and d6 metals Pt(I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
