1122-95-8Relevant academic research and scientific papers
Do electrostatic interactions with positively charged active site groups tighten the transition state for enzymatic phosphoryl transfer?
Nikolic-Hughes, Ivana,Rees, Douglas C.,Herschlag, Daniel
, p. 11814 - 11819 (2004)
The effect of electrostatic interactions on the transition-state character for enzymatic phosphoryl transfer has been a subject of much debate. In this work, we investigate the transition state for alkaline phosphatase (AP) using linear free-energy relationships (LFERs). We determined fcat/K M for a series of aryl sulfate ester monoanions to obtain the Bronsted coefficient, βIg, and compared the value to that obtained previously for a series of aryl phosphorothioate ester dianion substrates. Despite the difference in substrate charge, the observed Bronsted coefficients for AP-catalyzed aryl sulfate and aryl phosphorothioate hydrolysis (-0.76 ± 0.14 and -0.77 ± 0.10, respectively) are strikingly similar, with steric effects being responsible for the uncertainties in these values. Aryl sulfates and aryl phosphates react via similar loose transition states in solution. These observations suggest an apparent equivalency of the transition states for phosphorothioate and sulfate hydrolysis reactions at the AP active site and, thus, negligible effects of active site electrostatic interactions on charge distribution in the transition state.
Modulating charge carrier density and mobility in doped graphene by covalent functionalization
Arellano, Luis M.,Yue, Sun,Atienzar, Pedro,Gómez-Escalonilla, María J.,Ortega-Higueruelo, Francisco J.,Fierro, José Luis G.,García, Hermenegildo,Langa, Fernando
, p. 9999 - 10002 (2019)
Covalent B-functionalization of B-doped graphene has been performed for the first time. The electronic properties and Hall effect of functionalized N- and B-doped graphene can be tuned by tailoring the electron-donating/-withdrawing properties of the organic addend.
Bivalent tin(II)-4-methoxyphenoxide: synthesis, characterization, reactivity and antifungal activity
Chaudhry,Bandna, Kumari,Bhatt,Sharma, Neeraj,Sagar, Anand
experimental part, p. 391 - 400 (2009/10/09)
Bivalent tin(II)-4-methoxyphenoxide of composition Sn(OC6H 4OMe-4)2 (1) has been synthesized from the reaction of SnCl2 with bimolar amounts of 4-methoxyphenol and diethylamine in tetrahydrofuran and characteriz
Kinetics and mechanism of alkaline hydrolysis of aryl carbazates
Vlasak, Petr,Mindl, Jaromir
, p. 1401 - 1404 (2007/10/03)
Hydrlysis of aryl carbazates (H2NNHCO2Ar with Ar=phenyl, 3- or 4-chlorophenyl, 3- or 4-nitrophenyl, 4-methylphenyl and 4-methoxyphenyl) and/or their 2- or 3-methyl derivatives in aqueous buffers or sodium hydroxide solutions gives phenolate and sodium carbazate. the kinetics and acidity constants and thermodynamic parameters are given.By analysing the pH profiles, the activation entropy, and effects of the substituent on the aromatic ring it was found that aryl carbazates containing a methyl group in the 2 position are hydrolysed by a BAc2 mechanism and the others by an E2cB mechanism.The pH profiles of nitrophenyl carbazates show a maximum.The rate of decarboxylation of carbazic acid decreases with increasing pH value.
Free Radical Combination Reactions Involving Phenoxyl Radicals
Jonsson, M.,Lind, J.,Reitberger, T.,Eriksen, T. E.,Merenyi, G.
, p. 8229 - 8233 (2007/10/02)
The rates of phenoxyl radical reactions with the superoxide anion radical, O2.-, a peroxyl radical, HOC(CH3)2CH2OO., and an alkyl radical, HOC(CH3)2CH2., in aqueous solution have been measured for 15 different phenoxyl radicals by means of pulse radiolysis.In addition, the one-electron reduction potentials of 10 phenoxyl radicals have been determined.The fraction of electron transfer in the reaction of phenoxyl radicals with O2.- was determined by analysis of γ-irradiated samples.The experimental data can be accommodated by the Marcus theory for electron transfer, with the reorganization energy λ0 = 155 kJ/mol for the reaction between O2.- and phenoxyl radicals.
Trifluoromethyl pyridinyloxyphenoxy and pyridinylthiophenoxy propanoic acids and propanols and derivatives thereof and methods of herbicidal use
-
, (2008/06/13)
Compounds according to the following formula are useful as herbicidal agents: STR1 wherein the various substituents are defined hereinbelow.
Trifluoromethyl pyridinylthiophenoxy propanoic acids and propanols and derivatives thereof
-
, (2008/06/13)
Compounds of the formula below, all having trifluoromethyl substitution in at least one of the 3- and the 5-position in the pyridine ring with or without additional substitution at the converse position in the pyridine ring according to the following formula, are useful as herbicidal agents: STR1 wherein the substituents are defined hereinbelow.
Nouvelles syntheses de phenyl-4 allophanates
Al Sabbagh, Mohamed Mowafak,Calmon, Michelle,Calmon, Jean-Pierre
, p. 73 - 77 (2007/10/02)
The synthesis of eighteen alkyl or phenyl 4-phenylallophanates is described.The classical methods used for the preparation of allophanates - namely, condensation between an isocyanate and a carbamate, reaction between a urea and a carbonate, desulphurization of 3-thioallophanic acid esters - proved to be unsuitable for the synthesis of 4-phenylallophanic acid phenyl esters.Variously substituted 4-phenylallophanates can be obtained by reacting a chloroformate with a phenylurea in the presence of pyridine, which promotes the transfer of the carboxylate group.The occurence of electrondonating substituents, such as CH3, at the nitrogen atom receiving the carboxylate group promotes the reaction.The low yields observed for aliphatic esters can be accounted for by the instability of the alkyl chloroformate-pyridine complex.The structures of the derivatives synthesized was corroborated by the analysis of their n.m.r. and u.v. spectra. Non-commercial phenyl chloroformates were prepared by reacting phosgene with a sodium phenolate in the presence of anhydrous benzene.
