61066-33-9Relevant academic research and scientific papers
Facile synthesis of 1,2,3-tricarbonyls from 1,3-dicarbonyls mediated by cerium(IV) ammonium nitrate
Sivan, Akhil,Deepthi, Ani
supporting information, p. 1890 - 1893 (2014/03/21)
A mild and efficient protocol for the synthesis of vicinal tricarbonyl compounds from β-dicarbonyls in a single step using cerium(IV) ammonium nitrate as a catalytic oxidant is described. Ease of execution, wide substrate scope and the suitability for the synthesis of commercially important compounds like ninhydrin, alloxan and oxoline make this reaction particularly noteworthy.
pH dependent photooxygenation of xanthine and uric acid
Jain, Shubha,Kushwah, Archana,Jaiswal, Anjna
, p. 1289 - 1293 (2013/01/15)
Photooxygenation of xanthine and uric acid has been carried out by singlet oxygen in presence of methylene blue and rose bengal respectively in different media (neutral, acidic, alkaline) at different pH giving various products, which have been characterized by spectral data and elemental analysis.
Catalytic strategies for sustainable oxidations
Carraro, Mauro,Sartorel, Andrea,Scorrano, Gianfranco,Carofiglio, Tommaso,Bonchio, Marcella
experimental part, p. 1971 - 1978 (2009/04/07)
Several catalytic protocols for the oxidation of hydro-soluble substrates are presented that employ totally inorganic and robust polyoxometalate-based catalysts as well as porphyrin sensi-tizers, fullerenes and hybrid conjugates. Strategies for the imple-mentation of the system stability and efficiency are discussed.
Electrochemical oxidation of guanosine-5'-monophosphane at the pyrolytic graphite electrode
Gohal, Rajendra N.,Puri, Bal K.,Jain, Neena
, p. 832 - 837 (2007/10/03)
The electrochemical oxidation of guanosine-5'-monophosphate has been investigated in phosphate containing supporting electrolytes at pH 2.5-10.8 at a pyropytic graphite electrode by cyclic sweep voltammetry, spectral studies, controlled potential electrolysis and related techniques. The initial course of the electrode reaction has been deduced to involve a pH dependent 4e, 4H+ oxidation to give a diimine species which undergoes a series of chemical reactions to give different products. The kinetics of the decay of the UV-absorbing intermediate generated during electrooxidation has been studied at different pH values and first-order rate constants for the disappearance of the UV-absorbing intermediate have been calculated. The electrooxidation of guanosine-5'-monophosphate has been found to be an EC reaction (electrode reaction followed by chemical reactions) in which charge transfer is followed by competitive chemical reactions. The ultimate products of oxidation, urea riboside phosphate, alloxan (pyrimidine-2,4,5,6-(1H,3H)-tetraone) and a dimer were characterized by IR. 1H NMR and mass spectrometry at pH 3.4. A detailed interpretation of the redox mechanism for the formation of these products is presented.
Voltammetric and chronoamperometric investigations on the oxidation of 7-methylxanthine
Goyal, Rajendra N.,Singhal, Naveen K.
, p. 49 - 55 (2007/10/03)
Electrooxidation of 7-methylxanthine has been studied at pyrolytic graphite electrode in phosphate to be buffers of pH 2.0-10.9. A well defined 4e, 4H+ oxidation peak was noticed and an unstable diimine is formed whose half life has been found to be 40 ms by chronoamperometry. The reaction has been identified as EC in which charge transfer is followed by chemical reactions. The products have been characterized by m.p., 1HNMR and mass spectrum and a tentative reaction mechanism for their formation is suggested.
Differential pulse voltammetric investigations of uric acid in aqueous and micelle systems
Goyal, Rajendra N.,Ahmad, Shakeel,Rastogi, Arshi
, p. 283 - 289 (2007/10/03)
Differential pulse voltammetric behaviour of uric acid has been studied in phosphate buffers of pH 2.3- 11.2 at glassy carbon electrode. A well-defined 2e, 2H+, pH-dependent oxidation peak has been noticed and the conjugate base found as the electroactive species. Cationic surfactants have been found to significantly affect the Ep and ip. At concentrations below CMC, the change in Ep is predominantly due to adsorption effects, whereas at concentrations above CMC electrocatalysis and micellar catalysis shifted the Ep towards less positive potentials. The voltammetric behaviour in the presence of surfactants indicates that the 2e oxidation proceeds in two le steps and the formation of cationic free radical is suggested. The products of electrode reaction have been found to be the same in aqueous and micelle systems.
Comparison of electrochemical and enzymic oxidation of 7,9-dimethyluric acid
Goyal, Rajendra N.,Singhal, Naveen
, p. 276 - 282 (2007/10/03)
The oxidation of 7,9-dimethyluric acid has been studied in aqueous phosphate buffers in the pH range 2.3-10.0 at a variety of solid electrodes. The conjugate base is found as the electroactive species which on 2e, H+ oxidation gives an unstable diimine. The attack of water molecule on the diimine in a follow up chemical reaction gives a UV-absorbing intermediate which decomposes in a pseudo-first order reaction to give alloxan and 1,3-dimethylurea at pH 3.0 and 1,3-dimethylallantoin and 1,3-dimethyl-5-hydroxyhydantoin-5-carboxamide at pH 7.2. The electrochemical behaviour of dimethyluric acid at PGE, GCE and Ft electrodes is the same. A comparison of electrochemical behaviour with unsubstituted uric acid indicates that methyl groups at positions 7 and 9 shift the Ep towards less positive potential. However, the overall course of electrode reaction remains unchanged. The peroxidase catalysed oxidation of 7,9-dimethyluric acid also exhibites the same spectral and kinetic behaviour and hence it is concluded that electrochemical and enzymic oxidation proceed by an identical EC mechanism.
Electrochemical and peroxidase catalysed oxidation of 9-β-D-ribofuranosyluric acid 5′-monophosphate
Goyal, Rajendra N.,Rastogi, Arshi
, p. 2423 - 2429 (2007/10/03)
The electrochemical oxidation of 9-β-D-ribofuranosyluric acid 5′-monophosphate (UA-9R-5′-P) in aqueous solution has been studied in the pH range 2.10-10.0. The evidence strongly indicates that UA-9R-5′-P is oxidized in a 2e-, 2H+ reaction to give an unstable diimine which subsequently decomposes. A UV absorbing intermediate is observed during electrooxidation which decays in a pseudo first-order reaction to give alloxan, urea and ribosyl phosphate at pH 3.0. Controlled potential electrolysis results in the transfer of 2.0 ± 0.2 electrons per molecule and three major products are obtained at pH 7.0; allantoin, 5-hydroxyhydantoin-5-carboxamide and D-ribose. Tentative reaction schemes are proposed to explain the formation of these products. Oxidation of UA-9R-5′-P in the presence of peroxidase and H2O2 also generates an intermediate which has spectral and kinetic properties identical to those of the intermediate generated electrochemically. Thus, it is believed that electrochemical and enzymic oxidation of UA-9R-5′-P proceed by identical reaction mechanisms.
Electrochemical and enzymic oxidation of 9-methyluric acid at solid electrodes
Goyal, Rajendra N.,Jain, Ajay K.,Jain, Neena
, p. 1055 - 1062 (2007/10/02)
The electrochemical oxidation of 9-methyluric acid has been studied in the pH range 2.0-11.3 at pyrolytic graphite, platinum and glassy carbon electrodes.The oxidation was found to occur in a single 2e-, H+ pH-dependent reaction at all the three electrodes.Adsorption complications were observed at the pyrolytic graphite and glassy carbon electrodes whereas no such behaviour was observed at platinum.The UV-spectral changes and the kinetics of the decay of the UV-absorbing intermediate generated during the reaction were found to be essentially the same at all the three electrodes.The peroxidase catalyzed oxidation of 9-methyluric acid was also found to be similar to the electrochemical oxidation.The products of oxidation were the same at all the electrodes suggesting thereby that adsorptive action at the surface of PGE and GCE did not affect the EC mechanism
Rate of Decomposition of Murexide in Mixed Solvents: An Indicator for Proton Activity
Barrabass, Susanne,Stickdorn, Katrin,Knoche, Wilhelm
, p. 637 - 642 (2007/10/02)
The rate of decomposition of murexide depends strongly on the proton concentration.The observed rate constant correlates well with the relative permittivity of the solvent.This correlation is established by measurements in binary mixtures of water-dioxane and water-ethanol between 20 and 40 deg C and may be applied to the estimation of the proton concentration in the aqueous domains of microemulsions.
