16906-51-7Relevant academic research and scientific papers
Transition State Analysis of the Reaction Catalyzed by the Phosphotriesterase from Sphingobium sp. TCM1
Bigley, Andrew N.,Xiang, Dao Feng,Narindoshvili, Tamari,Burgert, Charlie W.,Hengge, Alvan C.,Raushel, Frank M.
, p. 1246 - 1259 (2019)
Organophosphorus flame retardants are stable toxic compounds used in nearly all durable plastic products and are considered major emerging pollutants. The phosphotriesterase from Sphingobium sp. TCM1 (Sb-PTE) is one of the few enzymes known to be able to hydrolyze organophosphorus flame retardants such as triphenyl phosphate and tris(2-chloroethyl) phosphate. The effectiveness of Sb-PTE for the hydrolysis of these organophosphates appears to arise from its ability to hydrolyze unactivated alkyl and phenolic esters from the central phosphorus core. How Sb-PTE is able to catalyze the hydrolysis of the unactivated substituents is not known. To interrogate the catalytic hydrolysis mechanism of Sb-PTE, the pH dependence of the reaction and the effects of changing the solvent viscosity were determined. These experiments were complemented by measurement of the primary and secondary 18-oxygen isotope effects on substrate hydrolysis and a determination of the effects of changing the pKa of the leaving group on the magnitude of the rate constants for hydrolysis. Collectively, the results indicated that a single group must be ionized for nucleophilic attack and that a separate general acid is not involved in protonation of the leaving group. The Br?nsted analysis and the heavy atom kinetic isotope effects are consistent with an early associative transition state with subsequent proton transfers not being rate limiting. A novel binding mode of the substrate to the binuclear metal center and a catalytic mechanism are proposed to explain the unusual ability of Sb-PTE to hydrolyze unactivated esters from a wide range of organophosphate substrates.
Potent and selective phosphopeptide mimetic prodrugs targeted to the Src homology 2 (SH2) domain of signal transducer and activator of transcription 3
Mandal, Pijus K.,Gao, Fengqin,Lu, Zhen,Ren, Zhiyong,Ramesh, Rajagopal,Birtwistle, J. Sanderson,Kaluarachchi, Kumaralal K.,Chen, Xiaomin,Bast, Robert C.,Liao, Warren S.,McMurray, John S.
experimental part, p. 3549 - 3563 (2011/07/30)
Signal transducer and activator of transcription 3 (Stat3), a target for anticancer drug design, is activated by recruitment to phosphotyrosine residues on growth factor and cytokine receptors via its SH2 domain. We report here structure-activity relation
INHIBITORS OF STAT3 AND USES THEREOF
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Page/Page column 39; 46-47, (2010/11/03)
Compounds which inhibit the activity of signal transducer and activator of transcription 3 (STAT3) are provided together with methods of making and using the same. The compounds are designed to bind to the SH2 domain of STAT3, preventing STAT3 from bindin
Lewis acid catalyzed Diels-Alder reactions of two useful dienyl phosphate esters
Liu, Hsing-Jang,Feng, Waiseng Martin,Kim, Jeung Bea,Browne, Eric N. C.
, p. 2163 - 2175 (2007/10/02)
The Lewis acid catalyzed Diels-Alder reactions of dienyl phosphate esters 1 and 2 were examined. 2-Diethylphosphoryloxy-1,3-butadiene (1) was found to react with a variety of α,β-unsaturated carbonyl compounds under Lewis acid catalysis with excellent reg
Transfer of the Diethoxyphosphoryl Group between Imidazole and Aryloxy Anion Nucleophiles
Ba-Saif, Salem,Williams, Andrew
, p. 2204 - 2209 (2007/10/02)
Rate constans have been measured for reaction of imidazole with aryl diethyl phosphate (k1) and of aryloxy anions with N-(diethoxyphosphoryl)imidazolium ion (k-1) in aqueous solution at 25 deg C; they obey the following linear Broensted equations: log k1 = -1.02pKArOH + 1.83 (n = 6, r = 0.989); log k-1 = 0.85pKArOH - 0.48 (n = 10, r = 0.957).The value of βeq (1.87) obtained from βlg and βnuc supports a previously determined value (1.83) for the transfer of the neutral phosphoryl group from phenolate ion nucleophiles.The pKaof (diethoxyphosphoryl)imidazolium ion is 6.04.The equilibrium constant for reaction of 4-nitrophenyl diethyl phosphate with imidazole is 5.9 x 10-6; in the case of the aryl ester from phenol with pKArOH = 4.34 the equilibrium constant is calculated to be unity.The Broensted βeq data are used to calibrate effective charges derived from previously measured βlg values for attack of nucleophiles at phosphorus bearing phenolate ion leaving groups.
THE LEWIS ACID CATALYZED DIELS-ALDER REACTION OF 2-DIETHYLPHOSPHORYLOXY-1,3-BUTADIENE, AN OXYGEN-SUBSTITUTED DIENE OF UNUSUAL STABILITY
Liu, Hsing-Jang,Feng, Waiseng Martin
, p. 1777 - 1786 (2007/10/02)
The title compound 2 was shown to be a useful oxygen-substituted diene in the Lewis acid catalyzed Diels-Alder reaction.It reacts with a variety of dienophiles under mild conditions with excellent regioselectivity.
