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Topic: Reactive intermediates


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 Reactive intermediate - Wikipedia, the free encyclopedia
In chemistry a reactive intermediate is a short-lived high energy highly reactive molecule.
Reactive intermediates help explain how a chemical reaction takes place.
Most chemical reactions take more than one elementary step to complete, and a reactive intermediate is an unstable product that only exists in one of the intermediate steps.
en.wikipedia.org /wiki/Reactive_intermediate   (267 words)

  
 eec
Spectroscopic signatures are an important tool for the chemist in identifying what reactive species are present in a complicated mixture; this is extremely important, as the reactivity of the species excludes the ability to extract them and take them away for analysis.
Thermal dissociation has proved to be a general method of making reactive intermediates, while microwave discharge methods have proved very suitable for the generation of halogen atoms which can subsequently be employed for the generation of transient species via rapid halogen atom-molecule reactions.
The electronic structure calculations proposed as part of this project underpin the experimental programme — to study the electronic structure of reactive intermediates with uv photoelectron spectroscopy, to study the structure and reactivity of clusters and their ions, and to study molecular excited states by laser spectroscopy.
www.science.uva.nl /research/imc/reactive_intermediates/eec.html   (3467 words)

  
 University of Rochester Chemistry Department Joshua L. Goodman   (Site not responding. Last check: 2007-11-05)
These intermediates can be quite difficult to characterize because they are often unstable, highly reactive and short-lived.
Professor Goodman's research goals involve the experimental challenge of preparing such reactive intermediates and accurately describing their physical and chemical properties (structure, energetics and kinetics).
Radicals, biradicals, carbenes, and ion radicals are all highly reactive species that have been postulated as reactive intermediates in organic reactions.
www.chem.rochester.edu /Faculty/Goodman.html   (469 words)

  
 Silicon & Germanium Reactive Intermediates
Most, however, are highly reactive species with lifetimes on the order of microseconds or less in the gas phase or in solution.
Understanding their chemistry is important from the fundamental perspective of bonding and reactivity in main group chemistry, and also because they are involved as reactive intermediates in a wide variety of thermal and photochemical reactions in organosilicon chemistry, many of which are important technologically.
Cam Harrington are examining the reactivity of the germanium analogues of some of these compounds, such as 1,1-diphenylgermene (5) and the (1-germa)hexatriene derivative 6, which are prepared in the same ways as the corresponding silicon compounds 4 and 2.
www.chemistry.mcmaster.ca /~wjl/leigh/res-sil.html   (1298 words)

  
 Reactive Nitrogen Intermediates Have a Bacteriostatic Effect on Mycobacterium tuberculosis In Vitro -- Firmani and ...
and reactive nitrogen intermediates (RNI) (7, 12, 16, 17, 18,
Release of reactive nitrogen intermediates and reactive oxygen intermediates from mouse peritoneal macrophages.
Mycobacterium tuberculosis CDC1551 is resistant to reactive nitrogen and oxygen intermediates in vitro.
jcm.asm.org /cgi/content/full/40/9/3162   (2533 words)

  
 Zaleski Group | Research Interests | Photodynamic Therapy Agents
By incorporating intensely absorbing functionalities into reactive molecules, reactive species can be locally generated in vivo in order to target specific locations within the body while minimizing the damage that these species can cause elsewhere.
Typical photochemically reactive species containing diazo or enediyne groups have employed high energy, UV photons to generate reactive intermediates.
These experiments reveal information about the electronic structure and reactive intermediates of these molecules by allowing investigation of their excited states.
www.indiana.edu /~zalegrp/Research/PDTagents.htm   (355 words)

  
 Reactive oxygen intermediates stimulate interleukin-6 production in human bronchial epithelial cells -- Yoshida et al. ...
Reactive oxygen intermediates (ROIs) play an important role in the initiation and progression of lung diseases.
Reactive oxygen intermediates cause rapid release of the interleukin-1 decoy receptor from human myelomonocytic cells.
Reactive oxygen intermediates induce regulated secretion of von Willebrand factor from cultured human vascular endothelial cells.
ajplung.physiology.org /cgi/content/full/276/6/L900   (3780 words)

  
 Rybak-Akimova Research Group - Research
High-valent iron oxo species are supported by porphyrin ligands and function as reactive intermediates in oxidations catalyzed by heme complexes.
In order to obtain the answers relevant to rapid catalytic reactions, the individual reaction steps (formation of the intermediate from the iron complex and the oxidant, and the interaction between the intermediate and the substrate) should also be rapid.
Detailed low-temperature single- and multi-mixing stopped-flow kinetic studies provide an information on the rates of formation of reactive intermediates, and the rates of their interactions with the substrates.
ase.tufts.edu /chemistry/rybak/Kinetics.htm   (640 words)

  
 Department of Chemistry and Biochemistry - Faculty Page - Douglas A. Klumpp   (Site not responding. Last check: 2007-11-05)
We seek new methods of generating reactive intermediates and new chemical systems that are prone to forming reactive species in solution.
We have taken advantage of this reactivity in synthetic reactions (for example, in the preparations of phenytoin, an important anti-epileptic drug, eq.
Through the study of these reactive electrophiles, we strive to gain further understanding of chemical reactivity and develop new methods of organic synthesis.
www.chembio.niu.edu /chembio/klumpp.html   (561 words)

  
 Silicon & Germanium Reactive Intermediates
More recent work has involved the study of the reactivity of (aryl-) substituted 1,1-diarylsilenes, of which Ph Si=CH) is the parent, and Christine and former postdoctoral fellow Xiaojing Li have used them for further mechanistic studies of the addition of alcohols, carboxylic acids, ketones, amines, and alkoxysilanes to transient silenes in solution.
Former students Nick Toltl and Tracy Morkin carried out studies of the reactivity of the germanium analogues of some of these compounds, such as 1,1-diphenylgermene (5) and the (1-germa)hexatriene derivative 6, which are prepared in the same ways as the corresponding silicon compounds 4 and 2.
Cam Harrington, and Greg Potter were both interested mainly in germanium reactive intermediates; Greg's MSc thesis continued our studies of diarylgermene (Ar Ge=CH) reactivity and diarylgermacyclobutane photochemistry, while Cam's PhD thesis concerns the reactivity of diaryl- and dialkylgermylenes formed by photolysis of 1,1-disubstituted 1-germacyclopent-3-ene derivatives (13) and other appropriately-structured organogermanium compounds.
www.chemistry.mcmaster.ca /leigh/res-si_ge.html   (1568 words)

  
 UA College of Pharmacy Hosts Scientific Conference on `Biological Reactive Intermediates' Jan. 4-7   (Site not responding. Last check: 2007-11-05)
Terrence Monks, co-chair of the conference and head of the College of Pharmacy Department of Pharmacology and Toxicology, explains that biological reactive intermediates, or BRIs, are metabolites of drugs or environmental chemicals that interact with various macromolecules within the body.
The International Symposia on Biological Reactive Intermediates began 30 years ago and is staged every five years through the work of a group of volunteers with interests in the field.
Topics at the January conference include BRIs and new reactive intermediate chemistry, proteomics approaches to BRI/protein interactions, global responses to BRIs, and BRIs in relation to drug development, idiosyncratic drug reactions, DNA damage and repair and chromatin structure and function.
www.ahsc.arizona.edu /opa/news/dec05/conference.htm   (382 words)

  
 Reactive Dyes Manufacturer, Reactive Dyes India, Reactive Dyes Black, Green, Reactive Dyes Orange, Dye Intermediates - ...   (Site not responding. Last check: 2007-11-05)
Star Dyes and Intermediates is manufacturer and exporter of Dyes and Dye Intermediates like Reactive Dyes, Direct Dyes, Acid Dyes, and Solvent Dyes from Ahmedabad, India.
In near future we would be able to supply Salt Free Reactive Dyes and Acid Dyes.
Reactive Dyes, Acid Dyes, Direct Dyes, Solvent Dyes and Dyes Intermediates are applicable on leather, textile, wool, silk, fur, nylon and paper.
www.stardyes.com /reactive-dyes.htm   (195 words)

  
 Involvement of Reactive Oxygen Intermediates in Spontaneous and CD95(Fas/APO-1)-Mediated Apoptosis of Neutrophils -- ...
Involvement of Reactive Oxygen Intermediates in Spontaneous and CD95(Fas/APO-1)-Mediated Apoptosis of Neutrophils -- Kasahara et al.
Involvement of Reactive Oxygen Intermediates in Spontaneous and CD95(Fas/APO-1)-Mediated Apoptosis of Neutrophils
The respiratory burst activity of phagocytes is the essential metabolic events to the killing of ingested microbes by the reactive oxygen intermediates (ROI) generated by the multicomponent enzyme system of membrane-associated NADPH oxidase.
www.bloodjournal.org /cgi/content/full/89/5/1748   (5263 words)

  
 Endogenous generation of reactive oxidants and electrophiles and their reactions with DNA and protein -- Marnett et al. ...
Endogenous generation of reactive oxidants and electrophiles and their reactions with DNA and protein -- Marnett et al.
Reactive intermediates generated from superoxide and nitric oxide.
Reactive intermediates derived from amino acid, lipid, and carbohydrate oxidation.
www.jci.org /cgi/content/full/111/5/583   (5858 words)

  
 Transgenic tobacco plants with reduced capability to detoxify reactive oxygen intermediates are hyperresponsive to ...
Transgenic tobacco plants with reduced capability to detoxify reactive oxygen intermediates are hyperresponsive to pathogen infection -- Mittler et al.
Reactive oxygen intermediates (ROI) play a critical role in the defense of plants against invading pathogens.
PCD that occurs during the HR is accompanied by an increase in the production of reactive oxygen intermediates (ROI) (7-9).
www.pnas.org /cgi/content/full/96/24/14165   (5965 words)

  
 Release of Reactive Oxygen Intermediates (Superoxide Radicals, Hydrogen Peroxide, and Hydroxyl Radicals) and Peroxidase ...
Release of Reactive Oxygen Intermediates (Superoxide Radicals, Hydrogen Peroxide, and Hydroxyl Radicals) and Peroxidase in Germinating Radish Seeds Controlled by Light, Gibberellin, and Abscisic Acid -- Schopfer et al.
Grant JJ, Loake GJ (2000) Role of reactive oxygen intermediates and cognate redox signaling in disease resistance.
Jabs T (1999) Reactive oxygen intermediates as mediators of programmed cell death in plants and animals.
www.plantphysiol.org /cgi/content/full/125/4/1591   (5764 words)

  
 Amazon.com: Reactive Intermediates (Oxford Chemistry Primers): Books: Christopher J. Moody,Gordon H. Whitham   (Site not responding. Last check: 2007-11-05)
'This concise text concentrates on the last aspect of reactive intermediate chemistry; the important reactions of these electron-deficient species are laid out clearly and simply, with carefull chosen examples illustrating their use in organic synthesis.
Neutral reactive intermediates - radicals, carbenes, nitrenes, and arynes - have an interesting place within the history of organic chemistry.
This concise text concentrates on the last aspect of reactive intermediate chemistry; the important reactions of these electron-deficient species are laid out clearly and simply, with carefully chosen examples illustrating their use in organic synthesis.
www.amazon.com /Reactive-Intermediates-Oxford-Chemistry-Primers/dp/0198556721   (764 words)

  
 Ohio State chemist wins national award for study of reactive intermediates
Chemical reactions proceed not by simply mutating from one form to another, but more often via intermediate molecules that may exist for only billionths of a second.
Platz and his research team use high-tech techniques such as laser flashes to ‘freeze-frame’ reactive intermediates.
“We are studying compounds which bind pathogenic nucleic acid [the building blocks of genetic material], absorb visible light, generate reactive intermediates which damage the nucleic acid and inactivate the pathogen,” he said.
www.eurekalert.org /pub_releases/2001-08/acs-osc081501.php   (387 words)

  
 GOES Research   (Site not responding. Last check: 2007-11-05)
Once unambiguously identified and analyzed, their spectra provide means for monitoring reactive intermediates in a number of environments such as flames, the atmosphere, interstellar space, etc. Our laboratory often applies a number of complementary spectroscopic technologies to characterize as completely as possible the spectra, structure, and dynamics of important chemical intermediates.
Recently work in GOES has centered upon reactive intermediates present in the oxidation of organic molecules, particularly hydrocarbons.
These oxidation reactions are responsible for more than 2/3's of the world's energy production from the burning of fossil fuels and they also play key roles in the degradation of the teragram quantities of organic molecules injected annually into the earth's troposphere.
molspect.mps.ohio-state.edu /goes/index.html   (208 words)

  
 ORGANIC REACTIVE INTERMEDIATES AND MATERIALS CHEMISTRY
Reactive intermediates and reaction mechanisms; organic magnetic; and catalytic pathways to chemical intermediates; and hydridic-to-protonic hydrogen bonding.
It may vary from thermoneutral to very exothermic, with or without an intermediate, depending on substrate.
Kinetic, structural, and computional studies are underway to ask whether it is a one- or two-step process, and how general it is.
www.cem.msu.edu /~gradoff/brochf/Jackson.htm   (462 words)

  
 Chemically Reactive Intermediates and Pulmonary Xenobiotic Toxicity -- Gram 49 (4): 297 -- Pharmacological Reviews
reactive oxygen metabolites, it is not considered useful to attempt
Among the earliest clear demonstrations of the metabolic activation of a xenobiotic to a chemically reactive intermediate
The chemical nature of the reactive intermediates of 2-MF and 3-MF in rat lung microsomes was addressed by Ravindranath et
pharmrev.aspetjournals.org /cgi/content/full/49/4/297   (8594 words)

  
 Reactive Intermediates Student Exchange
: Reactive intermediates in biological systems; photochemistry in organized media; interfacial processes at biomembranes.
: Reactive intermediates in organosilicon, organogermanium, and organotin photochemistry, photochemical pericyclic reactions; far-UV photochemistry.
: Kinetic and mechanistic studies of organic reaction intermediates; organic photochemistry; two photon processes; photoreactions in organized media; laser techniques; chiral recognition; magnetic field effects; photoresists.
www.risecanada.ca   (804 words)

  
 .: Research - Richard Research Group :.
In solution, the overall activation barrier to reactions which proceed through such unstable intermediates is the thermodynamic barrier to formation of the intermediate.
The major problem faced by enzyme catalysts is reducing the activation barrier for formation of reactive intermediates at an enzyme active site.
Our work focuses on understanding the mechanism by which reactive intermediates for organic reactions are stabilized by interaction with the catalytic side chains at an enzyme active site.
www.acsu.buffalo.edu /~jrichard/research.html   (504 words)

  
 Inhaled Nitric Oxide Primes Lung Macrophages to Produce Reactive Oxygen and Nitrogen Intermediates -- WEINBERGER et al. ...
lung macrophages to release reactive oxygen and nitrogen intermediates.
of reactive nitrogen intermediates by alveolar macrophages in
Nitric oxide is a highly reactive molecule that has been reported to be directly cytotoxic to lung cells and tissue (6,
ajrccm.atsjournals.org /cgi/content/full/158/3/931   (4208 words)

  
 Structural analogues of reactive intermediates as inhibitors of glucosamine-6-phosphate synthase and phosphoglucose ...   (Site not responding. Last check: 2007-11-05)
Structural analogues of reactive intermediates as inhibitors of glucosamine-6-phosphate synthase and phosphoglucose isomerase.
Ten derivatives of d-hexitol-6-P, 5-phosphoarabinoate, or 6-phosphogluconate, structural analogues of putative cis-enolamine or cis-enolate intermediates, were tested as inhibitors of fungal GlcN-6-P synthase and PGI.
Molecular modeling studies revealed that interactions of the C1-C2 part of transition state analogue inhibitors with the respective areas demonstrating different distribution of molecular electrostatic potential (MEP) inside HPI and PGI active centers determined enzyme:ligand affinity.
glucosamine.researchtoday.net.cob-web.org:8888 /archive/3/6/349.htm   (282 words)

  
 Salmonella Pathogenicity Island 2 Mediates Protection of Intracellular Salmonella from Reactive Nitrogen Intermediates ...
of infection; RNI, reactive nitrogen intermediates; ROI, reactive
Reactive oxygen and nitrogen intermediates in the relationship between mammalian hosts and microbial pathogens.
Reactive oxygen and reactive nitrogen intermediates in innate and specific immunity.
www.jem.org /cgi/content/full/195/9/1155   (6288 words)

  
 intermediates - OneLook Dictionary Search
We found 2 dictionaries with English definitions that include the word intermediates:
Tip: Click on the first link on a line below to go directly to a page where "intermediates" is defined.
Intermediates : English-Chinese Dictionary of Graphic Communications (Big 5) [home, info]
www.onelook.com /?w=intermediates   (132 words)

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