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Nitrosyl
In organic chemistry, nitroso refers to a functional group in which the nitric oxide () group is attached to an organic moiety. As such, various nitroso groups can be categorized as ''C''-nitroso compounds (e.g., nitrosoalkanes; ), ''S''-nitroso compounds ( nitrosothiols; ), ''N''-nitroso compounds (e.g., nitrosamines, ), and ''O''-nitroso compounds (alkyl nitrites; ). Synthesis Nitroso compounds can be prepared by the reduction of nitro compounds or by the oxidation of hydroxylamines. Ortho-nitrosophenols may be produced by the Baudisch reaction. In the Fischer–Hepp rearrangement aromatic 4-nitrosoanilines are prepared from the corresponding nitrosamines. Properties Nitrosoarenes typically participate in a monomer–dimer equilibrium. The dimers, which are often pale yellow, are often favored in the solid state, whereas the deep-green monomers are favored in dilute solution or at higher temperatures. They exist as ''cis'' and ''trans'' isomers. Due to the stability o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barton Reaction
The Barton reaction, also known as the Barton nitrite ester reaction, is a photochemical reaction that involves the photolysis of an alkyl nitrite to form a δ-nitroso alcohol. Discovered in 1960, the reaction is named for its discoverer, Nobel Laureate Sir Derek Barton. Barton's Nobel Prize in Chemistry in 1969 was awarded for his work on understanding conformations of organic molecules, work which was key to realizing the utility of the Barton Reaction. The Barton reaction involves a homolytic RO–NO cleavage, followed by δ- hydrogen abstraction, free radical recombination, and tautomerization to form an oxime. Selectivity for the δ-hydrogen is a result of the conformation of the 6-membered radical intermediate. Often, the site of hydrogen atom abstraction can be easily predicted. This allows the regio- and stereo-selective introduction of functionality into complicated molecules with high yield. Due to its unique property at the time to change otherwise inert substrates, Bart ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
S-Nitrosothiol
In organic chemistry, ''S''-nitrosothiols, also known as thionitrites, are organic compounds or functional groups containing a nitroso group attached to the sulfur atom of a thiol. ''S''-Nitrosothiols have the general formula , where ''R'' denotes an organic group. Originally suggested by Ignarro to serve as intermediates in the action of organic nitrates, endogenous S-nitrosothiols were discovered by Stamler and colleagues (S-nitrosoalbumin in plasma and S-nitrosoglutathione in airway lining fluid) and shown to represent a main source of NO bioactivity ''in vivo''. More recently, S-nitrosothiols have been implicated as primary mediators of protein S-nitrosylation, the oxidative modification of cysteine thiol that provides ubiquitous regulation of protein function. S-Nitrosothiols have received much attention in biochemistry because they serve as donors of both the nitrosonium ion and of nitric oxide and thus best rationalize the chemistry of NO-based signaling in living ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitric Oxide
Nitric oxide (nitrogen oxide or nitrogen monoxide) is a colorless gas with the formula . It is one of the principal oxides of nitrogen. Nitric oxide is a free radical: it has an unpaired electron, which is sometimes denoted by a dot in its chemical formula (•N=O or •NO). Nitric oxide is also a heteronuclear diatomic molecule, a class of molecules whose study spawned early modern theories of chemical bonding. An important intermediate in industrial chemistry, nitric oxide forms in combustion systems and can be generated by lightning in thunderstorms. In mammals, including humans, nitric oxide is a signaling molecule in many physiological and pathological processes. It was proclaimed the "Molecule of the Year" in 1992. The 1998 Nobel Prize in Physiology or Medicine was awarded for discovering nitric oxide's role as a cardiovascular signalling molecule. Nitric oxide should not be confused with nitrogen dioxide (NO2), a brown gas and major air pollutant, or with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrosonium Ion
The nitrosonium ion is , in which the nitrogen atom is bonded to an oxygen atom with a bond order of 3, and the overall diatomic species bears a positive charge. It can be viewed as nitric oxide with one electron removed. This ion is usually obtained as the following salts: , (nitrosylsulfuric acid, more descriptively written ) and . The and salts are slightly soluble in acetonitrile . NOBF4 can be purified by sublimation at 200–250 °C and . is isoelectronic with CO, and . It arises via protonation of nitrous acid: :HONO + H+ NO+ + H2O Chemical properties Hydrolysis reacts readily with water to form nitrous acid: : For this reason, nitrosonium compounds must be protected from water or even moist air. With base, the reaction generates nitrite: : As a diazotizing agent reacts with aryl amines, , to give diazonium salts, . The resulting diazonium group is easily displaced (unlike the amino group) by a variety of nucleophiles. As an oxidizing agent , e.g. a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrosylation
Nitrosylation is the general term for covalent incorporation of a nitric oxide "nitrosyl" moiety into another (usually organic) molecule. There are multiple chemical mechanisms by which this can be achieved; including biological enzymes and industrial processes. The biological functions of nitrosylation are particularly important as ''S''-nitrosylation, the conjugation of NO to cysteine thiols in proteins, is an important part of cell signalling In biology, cell signaling (cell signalling in British English) or cell communication is the ability of a cell to receive, process, and transmit signals with its environment and with itself. Cell signaling is a fundamental property of all cellular .... Coordination of NO to transition metals to give metal nitrosyl complexes, is also referred to as nitrosylation. See also * Nitrosation References Chemical reactions Nitrogen cycle {{Chemistry-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baudisch Reaction
In organic chemistry, the Baudisch reaction is a process for the synthesis of nitrosophenols using metal ions. Although the products are of limited value, the reaction is of historical interest as an example of metal-promoted functionalization of aromatic substrates. History and Mechanism As described originally by Oskar Baudisch in 1939 and further developed by his colleague Cronheim in 1947, benzene, hydroxylamine, and hydrogen peroxide are combined. Baudisch proposed that the reaction proceeds first via the formation of nitroxyl (HN=O), by the oxidation of hydroxylamine hydrochloride with hydrogen peroxide, possibly catalysed by the cupric ions. : This can also be achieved by the reduction of nitrous acid with cuprous ions or by the action of cuprous ions and hydrogen peroxide on Piloty's acid. The nitroxyl (HN=O) then attacks the aromatic ring, giving a nitroso-cyclohexadiene which is rapidly hydroxylated before being oxidised by the peroxide to give the o-nitrosophenol as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saville Reaction
The Saville reaction is a chemical reaction in which mercury replaces a nitrosyl from a thiol group. It is used as a method of replacing the nitrosyl from the modified cysteine Cysteine (symbol Cys or C; ) is a semiessential proteinogenic amino acid with the formula . The thiol side chain in cysteine often participates in enzymatic reactions as a nucleophile. When present as a deprotonated catalytic residue, some ...s and thus can serve in research of the redox modification of different proteins.A scheme for the colorimetric determination of microgram amounts of thiols; Saville B. Analyst 83, 670 (1958) PN50818. References External links On use of Saville Reactions on Invitrogen page Name reactions {{reaction-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ligand
In coordination chemistry, a ligand is an ion or molecule ( functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's electron pairs, often through Lewis bases. The nature of metal–ligand bonding can range from covalent to ionic. Furthermore, the metal–ligand bond order can range from one to three. Ligands are viewed as Lewis bases, although rare cases are known to involve Lewis acidic "ligands". Metals and metalloids are bound to ligands in almost all circumstances, although gaseous "naked" metal ions can be generated in a high vacuum. Ligands in a complex dictate the reactivity of the central atom, including ligand substitution rates, the reactivity of the ligands themselves, and redox. Ligand selection requires critical consideration in many practical areas, including bioinorganic and medicinal chemistry, homogeneous catalysis, and environment ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transition Metal
In chemistry, a transition metal (or transition element) is a chemical element in the d-block of the periodic table (groups 3 to 12), though the elements of group 12 (and less often group 3) are sometimes excluded. They are the elements that can use d orbitals as valence orbitals to form chemical bonds. The lanthanide and actinide elements (the f-block) are called inner transition metals and are sometimes considered to be transition metals as well. Since they are metals, they are lustrous and have good electrical and thermal conductivity. Most (with the exception of group 11 and group 12) are hard and strong, and have high melting and boiling temperatures. They form compounds in any of two or more different oxidation states and bind to a variety of ligands to form coordination complexes that are often coloured. They form many useful alloys and are often employed as catalysts in elemental form or in compounds such as coordination complexes and oxides. Most are strongly paramag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Davis–Beirut Reaction
The Davis–Beirut reaction is ''N,N''-bond forming heterocyclization that creates numerous types of 2''H''-indazoles and indazolones in both acidic and basic conditions The Davis–Beirut reaction is named after Mark Kurth and Makhluf Haddadin's respective universities; University of California, Davis and American University of Beirut, and is appealing because it uses inexpensive starting materials and does not require toxic metals. : Mechanism in base The current proposed mechanism for the Davis–Beirut reaction in base was first published in 2005 by Kurth, Olmstead, and Haddadin. The reaction occurs when a ''N''-substituted 2-nitrobenzylamine is heated in the presence of base, such as NaOH and KOH, and an alcohol and includes the formation of a carbanion The reaction begins with the base removing a hydrogen (1) adjacent to the secondary amine-group, creating a carbanion. The carbanion then extracts an oxygen from the nitro-group (2), which is then subsequently protonated ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bartoli Indole Synthesis
The Bartoli indole synthesis (also called the Bartoli reaction) is the chemical reaction of ortho-substituted nitroarenes and nitrosoarenes with vinyl Grignard reagents to form substituted indoles. The reaction is often unsuccessful without substitution ortho to the nitro group, with bulkier ortho substituents usually resulting in higher yields for the reaction. The steric bulk of the ortho group assists in the ,3sigmatropic rearrangement required for product formation. Three equivalents of the vinyl Grignard reagent are necessary for the reaction to achieve full conversion when performed on nitroarenes, and only two equivalents when performed on nitrosoarenes. This method has become one of the shortest and most flexible routes to 7-substituted indoles. The Leimgruber-Batcho indole synthesis gives similar flexibility and regiospecificity to indole derivatives. One advantage of the Bartoli indole synthesis is the ability to produce indoles substituted on both the carbocyclic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indole
Indole is an aromatic heterocyclic organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. Th ... with the formula Carbon, C8Hydrogen, H7Nitrogen, N. It has a bicyclic structure, consisting of a six-membered benzene ring fused to a five-membered pyrrole ring. Indole is widely distributed in the natural environment and can be produced by a variety of bacteria. As an Cell signaling, intercellular signal molecule, indole regulates various aspects of bacterial physiology, including Bacterial spore, spore formation, plasmid stability, drug resistance, resistance to drugs, biofilm formation, and virulence. The amino acid tryptophan is an indole derivative and the precursor of the neurotransmitter serotonin. General properties and occurrence Indole is a solid at room temperature ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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