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New Reactions (new + reaction)
Selected AbstractsA New Reaction of N-Substituted Formamides with Trichloroethylene under Conditions of Phase-Transfer Catalysis (PTC).CHEMINFORM, Issue 5 2003Andrzej Jonczyk Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: A New Reaction of Cyclohexanone Enolate with Nitroarenes.CHEMINFORM, Issue 44 2001Nikolai Moskalev Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] New Reactions of Fluorinated 2,4-Dioxoesters with Aromatic Aldehydes.CHEMINFORM, Issue 47 2006Marina V. Pryadeina Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Redox Photochemistry of Thiouredopyrenetrisulfonate,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 6 2004Alexander B. Kottyar ABSTRACT 1-Thiouredopyrene-3,6,8-trisulfonate (TUPS) has recently been used as a photoinduced covalent redox label capable of reducing various cofactors of proteins. A new reaction of this dye, whereby its excited triplet state oxidizes suitable electron donors, is now reported. The characteristic difference spectrum of the reduced radical of TUPS is determined. We also observe the self-exchange electron transfer between two TUPS molecules in their triplet excited states and determine the reaction scheme and the rate constants of the various pathways in the process of triplet depletion. The ability of photoexcited TUPS to withdraw an electron from reduced cytochrome-c is also observed. It is thus demonstrated that TUPS is an appropriate photoinduced covalent redox label for initiating both the oxidative and reductive phases of electron transfer processes in biological macromolecules. [source] Organocatalytic Asymmetric Cyanosilylation of NitroalkenesCHEMISTRY - A EUROPEAN JOURNAL, Issue 26 2010Pablo Bernal New catalyst, new reaction: The unprecedented cyanosilylation of nitroalkenes can be efficiently catalyzed by a bifunctional quinine derivative with tetraalkylammonium cyanide and thiourea moieties. The activation of the nitroalkene by hydrogen bonding to the thiourea, together with the presence of an "active" cyanide, provides a new mode of activation that leads to products in high yields and good selectivities (see scheme). [source] Self-Propagating Domino-like Reactions in Oxidized GraphiteADVANCED FUNCTIONAL MATERIALS, Issue 17 2010Franklin Kim Abstract Graphite oxide (GO) has received extensive interest as a precursor for the bulk production of graphene-based materials. Here, the highly energetic nature of GO, noted from the self-propagating thermal deoxygenating reaction observed in solid state, is explored. Although the resulting graphene product is quite stable against combustion even in a natural gas flame, its thermal stability is significantly reduced when contaminated with potassium salt by-products left from GO synthesis. In particular, the contaminated GO becomes highly flammable. A gentle touch with a hot soldering iron can trigger violent, catastrophic, total combustion of such GO films, which poses a serious fire hazard. This highlights the need for efficient sample purification methods. Typically, purification of GO is hindered by its tendency to gelate as the pH value increases during rinsing. A two-step, acid,acetone washing procedure is found to be effective for suppressing gelation and thus facilitating purification. Salt-induced flammability is alarming for the fire safety of large-scale manufacturing, processing, and storage of GO materials. However, the energy released from the deoxygenation of GO can also be harnessed to drive new reactions for creating graphene-based hybrid materials. Through such domino-like reactions, graphene sheets decorated with metal and metal oxide particles are synthesized using GO as the in situ power source. Enhanced electrochemical capacitance is observed for graphene sheets loaded with RuO2 nanoparticles. [source] Self-Propagating Domino-like Reactions in Oxidized GraphiteADVANCED FUNCTIONAL MATERIALS, Issue 17 2010Franklin Kim Abstract Graphite oxide (GO) has received extensive interest as a precursor for the bulk production of graphene-based materials. Here, the highly energetic nature of GO, noted from the self-propagating thermal deoxygenating reaction observed in solid state, is explored. Although the resulting graphene product is quite stable against combustion even in a natural gas flame, its thermal stability is significantly reduced when contaminated with potassium salt by-products left from GO synthesis. In particular, the contaminated GO becomes highly flammable. A gentle touch with a hot soldering iron can trigger violent, catastrophic, total combustion of such GO films, which poses a serious fire hazard. This highlights the need for efficient sample purification methods. Typically, purification of GO is hindered by its tendency to gelate as the pH value increases during rinsing. A two-step, acid,acetone washing procedure is found to be effective for suppressing gelation and thus facilitating purification. Salt-induced flammability is alarming for the fire safety of large-scale manufacturing, processing, and storage of GO materials. However, the energy released from the deoxygenation of GO can also be harnessed to drive new reactions for creating graphene-based hybrid materials. Through such domino-like reactions, graphene sheets decorated with metal and metal oxide particles are synthesized using GO as the in situ power source. Enhanced electrochemical capacitance is observed for graphene sheets loaded with RuO2 nanoparticles. [source] Shock-tube and modeling study of acetaldehyde pyrolysis and oxidationINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 2 2008Kenji Yasunaga Pyrolysis and oxidation of acetaldehyde were studied behind reflected shock waves in the temperature range 1000,1700 K at total pressures between 1.2 and 2.8 atm. The study was carried out using the following methods, (1) time-resolved IR-laser absorption at 3.39 ,m for acetaldehyde decay and CH-compound formation rates, (2) time-resolved UV absorption at 200 nm for CH2CO and C2H4 product formation rates, (3) time-resolved UV absorption at 216 nm for CH3 formation rates, (4) time-resolved UV absorption at 306.7 nm for OH radical formation rate, (5) time-resolved IR emission at 4.24 ,m for the CO2 formation rate, (6) time-resolved IR emission at 4.68 ,m for the CO and CH2CO formation rate, and (7) a single-pulse technique for product yields. From a computer-simulation study, a 178-reaction mechanism that could satisfactorily model all of our data was constructed using new reactions, CH3CHO (+M) , CH4 + CO (+M), CH3CHO (+M) , CH2CO + H2(+M), H + CH3CHO , CH2CHO + H2, CH3 + CH3CHO , CH2CHO + CH4, O2 + CH3CHO , CH2CHO + HO2, O + CH3CHO , CH2CHO + OH, OH + CH3CHO , CH2CHO + H2O, HO2 + CH3CHO , CH2CHO + H2O2, having assumed or evaluated rate constants. The submechanisms of methane, ethylene, ethane, formaldehyde, and ketene were found to play an important role in acetaldehyde oxidation. © 2007 Wiley Periodicals, Inc. 40: 73,102, 2008 [source] Catalytic selective oxidation faces the sustainability challenge: turning points, objectives reached, old approaches revisited and solutions still requiring further investigationJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 9 2010Fabrizio Cavani Abstract This review documents some examples of recently developed technologies and new approaches currently being investigated in the field of catalytic selective oxidation, that may contribute to improving the sustainability of the chemical industry. Tools to reach this ambitious target include process integration, the development of new reactions for the valorization of renewables and new catalysts able to perform complex transformations in a single step. Copyright © 2010 Society of Chemical Industry [source] New Uses for the Burgess Reagent in Chemical Synthesis: Methods for the Facile and Stereoselective Formation of Sulfamidates, Glycosylamines, and SulfamidesCHEMISTRY - A EUROPEAN JOURNAL, Issue 22 2004K. C. Nicolaou Prof. Abstract Although the Burgess reagent (methoxycarbonylsulfamoyltriethylammonium hydroxide, inner salt) has found significant use in chemical synthesis as a dehydrating agent, almost no work has been directed towards its potential in other synthetic applications. As this article will detail, we have found that the Burgess reagent is remarkably effective at accomplishing a number of non-dehydrative synthetic tasks when applied to appropriate substrates, such as the formation of sulfamidates from 1,2-diols or epoxyalcohols, ,- and ,-glycosylamines from carbohydrates, and cyclic sulfamides from 1,2-aminoalcohols. Beyond delineating the power of these new reaction manifolds, we also describe the construction of a group of alternative Burgess-type reagents that extends the scope of these new reactions even further. [source] | ||||||||||