58965-69-8Relevant academic research and scientific papers
Spectroscopic studies on the formation of molecular complexes of sulfamethoxazole with novel 2,3,5-trichloro-6-alkoxy-1,4-benzoquinones
Ganesh,Balraj,Satheshkumar,Elango
, p. 312 - 320 (2013/02/23)
UV-Vis, 1H NMR, FT-IR, LC-MS and fluorescence spectral techniques were employed to investigate the mechanism of interaction of sulfamethoxazole with alkoxy substituted 2,3,5-trichloro-1,4-benzoquinones and to characterize the reaction products. The interactions of these quinones with sulfamethoxazole (SULF) were found to proceed through the formation of donor-acceptor complex, containing radical anion and its conversion to the product. Fluorescence quenching studies indicated that the interaction between the donor and the acceptors are spontaneous. Correlation of association constants of the CT complexes with Taft's polar and steric constants indicated that polar factor plays a significant role in governing the reactivity. The results indicated that the electronic effects of the substituents play significant role in governing the reactivity of the quinones when compared to steric factor.
Spectral and theoretical studies on the molecular complexes of azacyclonol with new π-acceptors, alkoxysubstituted 1,4-benzoquinones
Balraj,Satheshkumar,Ganesh,Elango, Kuppanagounder P.
, p. 157 - 164 (2013/03/28)
The molecular complexes of a series of new electron acceptors, 1,4-benzoquinones possessing variety of alkoxy substituents, with azacyclonol have been investigated using various spectral techniques such as UV-Vis, 1H NMR, FT-IR, fluorescence and LC-MS. The stoichiometry of the complexes was determined by Job's continuous variation method and was found to be 1:1, in all the cases. The results of equilibrium, and kinetic studies were well supported by ab initio DFT calculations. Correlation of formation constants of the complexes with Taft's polar and steric constants indicated that both these factors play significant role in governing the reactivity. Also, the results indicated that an increase in electron releasing property of the alkoxy group makes these acceptors increasingly weaker while an increase in steric property of the substituent decreased the formation constant.
Conversion of pentahalogenated phenols by microperoxidase-8/H2O2 to benzoquinone-type products
Osman, Ahmed M.,Posthumus, Maarten A.,Veeger, Cees,Van Bladeren, Peter J.,Laane, Colja,Rietjens, Ivonne M.C.M.
, p. 1319 - 1325 (2007/10/03)
This study reports the microperoxidase-8 (MP8)/H2O2-catalyzed dehalogenation of pentafluorophenol and pentachlorophenol, compounds whose toxic effects and persistence in the environment are well documented. The primary products of this dehalogenation reaction appear to be the corresponding tetrahalo-p-benzoquinones. Under the conditions used, the fluorinated phenol and its intermediate products are more susceptible to degradation than the corresponding chlorinated analogue and its products. The main degradation products of tetrachloro-p-benzoquinone and tetrafluoro-p- benzoquinone were identified as trichlorohydroxyp-benzoquinone and trifluorohydroxy-p-benzoquinone, respectively. This secondary conversion of tetrafluoro-p-benzoquinone and tetrachloro-p-benzoquinone was not mediated by MP8, but was driven by H2O2. Evidence is presented for a mechanism where H2O2 molecules and not hydroxide anions are the reactive nucleophilic species attacking the tetrahalo-p-benzoquinones. In addition to the formation of the trihalohydroxy-p-benzoquinones, the formation of adducts of the tetrahalo-p-benzoquinone products with ethanol, present in the incubation medium, was observed. The adduct from the reaction of tetrachloro-p- benzoquinone with ethanol was isolated and identified as trichloroethoxyquinone. Thus, the present paper describes a system in which the formation of tetrahalo-p-benzoquinone-type products by an oxidative heme- based catalyst could be unequivocally demonstrated.
