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1.
Ragunatharaddi R. Hosamani Nagaraj P. Shetti Sharanappa T. Nandibewoor 《Journal of Physical Organic Chemistry》2009,22(3):234-240
The kinetics of oxidation of antibiotic drug, ampicillin (AMP) by diperiodatoargentate (III) (DPA) in alkaline medium at a constant ionic strength of 0.25‐mol dm?3 was studied spectrophotometrically. The reaction between DPA and AMP in alkaline medium exhibits 1:2 stoichiometry (AMP:DPA). The reaction is of first order in [DPA] and has less than unit order in both [AMP] and [alkali]. Added periodate retarded the rate of reaction and intervention of free radicals was observed in the reaction. The oxidation reaction in alkaline medium has been shown to proceed via a DPA–AMP complex, which decomposes slowly in a rate‐determining step followed by other fast steps to give the products. The main products were identified by spot test, IR and NMR studies. The reaction constants involved in the different steps of the mechanism are calculated. The activation parameters with respect to slow step of the mechanism were computed and discussed and thermodynamic quantities were also determined. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
2.
Balesh A. Deganatti Nagaraj P. Shetti Sharanappa T. Nandibewoor 《Transition Metal Chemistry》2009,34(2):143-152
The oxidation of l-valine (l-val) by diperiodatocuprate(III) (DPC) in aqueous alkaline medium at a constant ionic strength of 3.0 × 10−3 mol dm−3 was studied spectrophotometrically at 298 K and follows the rate law;
where K
4, K
5 and K
6 are the equilibrium constants for the different steps involved in the mechanism, k is the rate constant for the slow step of the reaction. The appearance of [l-val] term in both numerator and denominator explains the observed less than unit order in [l-val]. Similarly the appearances of [H3IO6
2−] and [OH−] in the denominator obey the experimental negative less than unit order in [H3IO6
2−] and [OH−], respectively. The oxidation reaction in alkaline medium proceeds via a DPC-l-valine complex, which decomposes slowly in a rate determining step followed by other fast steps to give the products. The
main products were identified by spot test and spectroscopic studies. 相似文献
3.
The kinetics of oxidation of atenolol (ATN) by diperiodatocuprate(III) (DPC) in aqueous alkaline medium at a constant ionic strength of 0.10 mol dm−3 was studied spectrophotometrically. The reaction between DPC and ATN in alkaline medium exhibits 1:2 stoichiometry (ATN:DPC). The reaction is of first order in [DPC] and has less than unit order in both [ATN] and [alkali]. However, the order in [ATN] and [alkali] changes from first order to zero order as their concentration increase. Intervention of free radicals was observed in the reaction. Increase in periodate concentration decreases the rate. The oxidation reaction in alkaline medium has been shown to proceed via a monoperiodatocuprate(III)–ATN complex, which decomposes slowly in a rate-determining step followed by other fast steps to give the products. The main oxidative products were identified by spot test, IR, NMR and LC–ESI-MS studies. The reaction constants involved in the different steps of the mechanism are calculated. The activation parameters with respect to slow step of the mechanism are computed and discussed, and thermodynamic quantities are also determined. 相似文献
4.
The kinetics of oxidation of L-cystine (L-CYS) by diperiodatocuprate (III) (DPC) in aqueous alkaline medium at a constant
ionic strength of 0.20 mol/1 was studied spectrophotometrically at 298 K. The reaction between DPC and L-cystine in alkaline
medium exhibits 1: 4 stoichiometry (L-cystine: DPC = 1: 4). The reaction is of first order in [DPC] and has less than unit
order in [L-CYS] and [alkali], negative fractional order in [periodate] and intervention of free radicals was observed in
the reaction. The oxidation reaction in alkaline medium has been shown to proceed via a monoperiodatocuprate(III)-L-ystine
complex, which decomposes slowly in a rate determining step followed by other fast steps to give the products. The main products
were identified by spot test, IR and GC-MS. The reaction constants involved in the different steps of the mechanism are calculated.
The activation parameters with respect to slow step of the mechanism are computed and discussed and thermodynamic quantities
were also determined. 相似文献
5.
S. Supriya Guddekoppa S. Ananthnag Vijayendra S. Shetti B.M. Nagaraja Gurumurthy Hegde 《应用有机金属化学》2020,34(3):e5384
A new heterogeneous catalyst was synthesized by immobilizing Pd on areca nut kernel-derived carbon nanospheres (CNSs). The CNSs, without any further activation processes, accommodated 3% of Pd on their surface. The new Pd/CNS material was used for the reduction of nitroarenes and Suzuki–Miyaura coupling of bromoarenes with aryl boronic acids. The reactions were conducted under microwave irradiation at 160 °C using 12 mol% of Pd/CNS (0.36% actual Pd content). The reduction of nitroarenes into their respective amino compounds was achieved in 10–20 min (conversion up to 100%); by contrast, the Suzuki–Miyaura reactions yielded up to 98% at 150 °C with 10 mol% of Pd/CNS catalyst. The products were identified using gas chromatography and nuclear magnetic resonance spectroscopy. The catalyst was isolated from reaction mixture and reused without any significant loss in the activity. Thus, the present work introduces one-pot-derived porous CNSs as efficient catalytic support to Pd, establishing an alternative to existing Pd/C in terms of cost and efficiency. 相似文献
6.
Umesh S. Devarushi Nagaraj P. Shetti Shikandar D. Bukkitgar Suresh M. Tuwar 《Russian Journal of Electrochemistry》2018,54(10):760-768
Valacyclovir (VCH) is an antiviral drug, used in the management of viral infections such as herpes simplex and varicella-zoster in humans. It is rapidly converted to acyclovir which has antiviral activity against herpes simplex virus types 1 (HSV-1) and 2 (HSV-2) and Varicella-zoster virus (VZV) both in vitro and in vivo. Electrochemical behavior was studied using cyclic voltammetric method, and the analytical application was studied using differential pulse voltammetric technique. The process on the surface of electrode was found to be irreversible and diffusion controlled. The charge transfer coefficient, heterogeneous rate constant, the number of electron transferred and activation parameters were calculated. Possible free radical reaction mechanism taking place on the surface of electrode was proposed. Calibration plot constructed using differential pulse voltammetric technique and applied for quantitative analysis in pharmaceutical and human urine sample. Limit of detection (LOD) and limit of quantification (LOQ) were calculated and found to be 0.028 and 0.09 μM, respectively. The present work describes the electrochemical behavior of an antiviral drug, VCH and its determination in pharmaceutical samples. The method shows the development of a sensor for selective and sensitive determination of VCH. 相似文献
7.
Electron paramagnetic resonance (EPR) spectroscopy of reactive superoxo-vanadium(V) species in vanadosilicate molecular sieves (microporous VS-1 and mesoporous V-MCM-41) generated on contact with H2O2, tert-butyl hydroperoxide (TBHP), or (H2+O2) is reported for the first time. By suitable choice of the silicate structure, solvent, and oxidant, we could control the vanadium-(O2-*) bond (i.e., the V-O bond) covalency, the mode of O-O cleavage (in the superoxo species), and, therefore, chemoselectivity in the oxidation of n-hexane: Oxidation by TBHP over V-MCM-41, for example, yielded 27.2% of (n-hexanol+n-hexanal+n-hexanoic acid), among the highest chemoselectivities for oxidation of the terminal -CH3 in a linear paraffin reported to date. Over these vanadosilicates, oxidation of the primary C-H bond occurs only via a homolytic O-O bond cleavage; the secondary C-H bond oxidations may proceed via both the homo- and heterolytic O-O cleavage mechanisms. 相似文献
8.
Kamal A Devaiah V Reddy KL Rajendar Shetti RV Shankaraiah N 《Journal of combinatorial chemistry》2007,9(2):267-274
A versatile method for the solid-phase synthesis of imidazo[1,2-a]pyridine-based derivatives, imidazo[1,2-a]pyridine-8-carboxamides, has been developed. They were obtained by treatment of the amino group of the polymer-bound 2-aminonicotinate with different alpha-haloketones, followed by halogenation at the 3-position of the polymer-bound imidazo[1,2-a]pyridine. The derived polymer-bound imidazo[1,2-a]pyridines 5, 6, and 7 were finally cleaved from the solid-support with an excess of primary or secondary amines. The final crude products were purified from excess amines by solid-supported liquid-liquid extraction (SLE). 相似文献
9.
Nagaraj P. Shetti Rajesh N. Hegde Sharanappa. T. Nandibewoor 《Central European Journal of Chemistry》2009,7(4):929-937
Oxidation of an amino acid, L-tyrosine (L-Tyr) by diperiodatocuprate(III) (DPC) in alkaline medium at a constant ionic strength
of 0.1 mol dm−3 was studied spectrophotometrically at different temperatures (288.1–313.1 K). The reaction between DPC and L-Tyr in alkaline
medium exhibits 1:4 stoichiometry (L-Tyr:DPC). Intervention of free radicals was observed in the reaction. Based on the observed
orders and experimental evidence, a mechanism involving monoperiodatocuprate(III) (MPC) as the reactive oxidant species has
been proposed. A suitable mechanism is proposed through the formation of a complex and free radical intermediate. The products
were identified by spot test and characterized by spectral studies. The reaction constants involved in the different steps
of the mechanism were calculated. The activation parameters with respect to slow step of the mechanism were computed and are
discussed. The thermodynamic quantities were determined for different equilibrium steps. Isokinetic temperature was also calculated
and found to be 252.3 K.
相似文献
10.
Nagaraj P. Shetti Shweta J. Malode Davalasab Ilager Kakarla RaghavaReddy Shyam S. Shukla Tejraj M. Aminabhavi 《Electroanalysis》2019,31(6):1040-1049
In this work, electrochemical detection of molinate herbicide was studied by developing a novel sensor based on carbon paste incorporated with zinc oxide (ZnO) nanoparticles using cyclic (CV) and square wave voltammetric (SWV) techniques. Molinate exhibited one well resolved peak at pH of 3.0 phosphate buffer solution (PBS), which was irreversible. The lowest possible detection limit of 1.0×10?8 M was achieved in the concentration range of 0.002 μM to 0.25 μM. The modifying ability of ZnO nanoparticles was responsible for such a low level sensing in water and soil samples. 相似文献