- A highly stereoselective oxidation and an easy one pot elimination methodology for 3-allyl-3-phenylthio-β-lactams
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A novel, facile, highly efficient and stereoselective protocol for the synthesis of cis-3-allyl-3-phenylsulfinyl-β-lactams and 3-allylidene-β-lactams from cis-3-allyl-3-phenylthio-β-lactams using Selectfluor both as an oxidizing agent and as an eliminating agent with temperature as a control parameter over the reaction outcome has been reported. The methodology is able to conquer the earlier reported shortcomings of long reaction time (24–90 hrs.) and lack of control over product ratio. The synthesized compounds will serve as important synthons for compounds of enhanced biological activity and potency.
- Bari, Shamsher S.,Nagpal, Reshma,Pandey, Suvidha,Thakur, Aarti,Thapar, Renu
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- RETRACTED ARTICLE: Design, synthesis, and biological evaluation of heterotetracyclic quinolinone derivatives as anticancer agents targeting topoisomerases
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A series of thiochromeno[2,3-c]quinolin-12-one derivatives with various substitutions were synthesized and evaluated as topoisomerase (Topo) inhibitors. Six (8, 10, 12, 14, 19, and 26) of 23 compounds showed strong inhibitory activities against Topo-media
- Lee, Jiann-Fong,Chang, Ting-Yu,Liu, Zheng-Fang,Lee, Nian-Zhe,Yeh, Yen-Hsiu,Chen, Yi-Song,Chen, Tsung-Chih,Chou, Hao-Syun,Li, Tsai-Kun,Lee, Sung-Bau,Lin, Mei-Hsiang
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- Competitive behavior of nitrogen based axial ligands in the oxovanadium(IV)-salen catalyzed sulfoxidation of phenylmercaptoacetic acid
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The sulfoxidation of twelve phenylmercaptoacetic acids (PMAA) by H2O2 catalyzed by three oxovanadium(IV)-salen complexes, having varied substituents on PMAA and salen with regard to their position, size and inductive effect, has been performed spectrophotometrically in 100percent acetonitrile medium. Three nitrogen bases (NB), pyridine (Py), imidazole (ImH) and 1-methylimidazole (MeIm), were used as axial ligands. It has been found that the rate of sulfoxidation is not only tuned by the substituents on PMAA and salen, but it is also varied by the addition of nitrogen bases. The observed order of retardation found among the different nitrogen bases is ImH > MeIm > Py. The rate of reaction decreases with the increase in concentration of the NB axial ligands. The strongly binding ImH shows the least reactivity. Hydroperoxovanadium(V)-salen has been proposed as the sole active oxidizing species. A detailed mechanistic study reveals that the low rate constant values in the presence of the nitrogen base is due to the existence of competition of NB with H2O2 and PMAA during the formation of active species and the coordination of PMAA with active species, respectively. Both electron donating and electron withdrawing substituents on PMAA retard the sulfoxidation rate significantly. The Hammett correlation between the rate constants and substituent constants shows a non-linear concave downward curve which is explained by the existence of two different rate determining steps within the same mechanism; coordination of PMAA with the active species for electron withdrawing substituents and transfer of oxygen to PMAA for electron donating substituents. All the experimental observations are explained by proposing a suitable mechanism.
- Kavitha, C.,Subramaniam, P.
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- Studies towards synthesis and Lewis acid catalysed functionalization of 3-(4′-substitutedphenylthio)-azetidin-2-ones
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Abstract: Medicinal chemistry of heterocycles especially β-lactams have been an important discovery in today’s mankind. β-Lactam nucleus is structural feature and core of the biological activity of one of most successful classes of therapeutics to date ch
- Bari, Shamsher S,Pandey, Suvidha,Reshma,Thakur, Aarti,Thapar, Renu
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- The synthesis and characterization of tetramic acid derivatives as Mdm2-p53 inhibitors
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We present syntheses, prediction of tautomer forms and activities of the second generation of the Mdm2-p53 inhibitors that are based on the tetramic acid scaffold. The inhibitors do not contain 6-chloroindole. Binding of these compounds to Mdm2 was checked by two orthogonal methods: the fluorescence polarization and the 1H-15N HSQC NMR titration experiments. We discovered that the 3-phenylthio-substituted tetramic acid derivatives exist in solution solely in their enol forms which is in contrast to the similar 3-aliphatic substituted derivatives. The inhibitory (Ki) and dissociation (KD) constants are in low micromolar ranges with the best binding compound 9a having KD = 2.9 μM. Furthermore, our data show that the compounds indeed bind to the p53-binding pocket of Mdm2 and do not cause dimerization of Mdm2. The current work provides solid base for further rational design of the Mdm2/p53 inhibitors.
- Muszak, Damian,?abuzek, Beata,Brela, Mateusz Z.,Twarda-Clapa, Aleksandra,Czub, Miroslawa,Musielak, Bogdan,Surmiak, Ewa,Holak, Tad A.
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p. 161 - 174
(2019/04/26)
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- FMS-LIKE TYROSINE KINASE INHIBITORS
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Provided are compounds of formula (I-1) -(I-4),which can be used as FLT3 inhibitors and for treatment and/or prevention of tumors.
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Paragraph 0060; 0072
(2019/10/29)
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- FMS-LIKE TYROSINE KINASE INHIBITORS
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The present invention relates to Fms-like tyrosine kinase (FLT3) inhibitors. The present invention provides novel 4-quinolinone derivatives used as FLT3 inhibitors and for treatment and/or prevention of tumors.
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Page/Page column 25; 29
(2020/03/31)
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- Electrophilic and nucleophilic pathways in ligand oxide mediated reactions of phenylsulfinylacetic acids with oxo(salen)chromium(V) complexes
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The mechanism of oxidative decarboxylation of phenylsulfinylacetic acids (PSAA) by oxo(salen)Cr(V)+ ion in the presence of ligand oxides has been studied spectrophotometrically in acetonitrile medium. Addition of ligand oxides (LO) causes a red shift in the λmax values of oxo(salen) complexes and an increase in absorbance with the concentration of LO along with a clear isobestic point. The reaction shows first-order dependence on oxo(salen)-chromium(V)+ ion and fractional-order dependence on PSAA and ligand oxide. Michaelis-Menten kinetics without kinetic saturation was observed for the reaction. The order of reactivity among the ligand oxides is picoline N-oxide > pyridine N-oxide > triphenylphosphine oxide. The low catalytic activity of TPPO was rationalized. Both electron-withdrawing and electron-donating substituents in the phenyl ring of PSAA facilitate the reaction rate. The Hammett plots are non-linear upward type with negative ρ value for electron-donating substituents, (ρ- = -0.740 to -4.10) and positive ρ value for electron-withdrawing substituents (ρ+ = +0.057 to +0.886). Non-linear Hammett plot is explained by two possible mechanistic scenarios, electrophilic and nucleophilic attack of oxo(salen)chromium(V)+-LO adduct on PSAA as the substituent in PSAA is changed from electron-donating to electron-withdrawing. The linearity in the log k vs. Eox plot confirms single-electron transfer (SET) mechanism for PSAAs with electron-donating substituents.
- Subramaniam,Sugirtha Devi,Anbarasan
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p. 164 - 173
(2016/06/06)
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- Importance of ground state stabilization in the oxovanadium(IV)-salophen mediated reactions of phenylsulfinylacetic acids by hydrogen peroxide – Non-linear Hammett correlation
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A systematic study on the oxidative decarboxylation of a series of phenylsulfinylacetic acids (PSAA) by hydrogen peroxide with four oxovanadium(IV)-salophen catalysts in 100% acetonitrile medium is presented. The hydroperoxovanadium(V)-salophen generated from the reaction mixture is identified as the bonafide active oxidizing species. Introduction of electron donating groups (EDG) in the oxovanadium(IV)-salophen catalyst and electron withdrawing groups (EWG) in PSAA enhances the reactivity, whereas EWG in the catalyst and EDG in PSAA have a retarding effect on the reaction. A Hammett correlation displays a non-linear downward curvature, which consists of two intersecting straight lines and the ρ value shifts from small positive to moderately high as the substituents change from EWG to EDG. The importance of the ground state stabilization of PSAA is inferred from a linear Yukawa–Tsuno plot. Based on the observed substituent effects and the spectral changes, a mechanism involving electrophilic attack of PSAA on the nucleophilic peroxo oxygen atom of the vanadium complex in the rate determining step followed by oxygen atom transfer is proposed.
- Subramaniam,Jeevi Esther Rathnakumari,Janet Sylvia Jaba Rose
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p. 496 - 503
(2016/07/21)
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- Modulation of catalytic activity by ligand oxides in the sulfoxidation of phenylmercaptoacetic acids by oxo(salen)chromium(V) complexes
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Mechanism of sulfoxidation of eleven para-substituted phenyl mercaptoacetic acids (PMAAs) by three oxo(salen)chromium(V)+PF6?complexes in the presence of different ligand oxides (LOs) such as triphenylphosphine oxide, pyridine N-oxide and 4-picoline N-oxide have been studied spectrophotometrically in 100% acetonitrile medium. Spectral and kinetic profiles establish the formation of adduct, O[dbnd]Cr(V)(salen)+-LO as the reactive intermediate in the catalytic cycle. The rate of sulfoxidation is found to be enhanced significantly by the addition of LOs and introduction of substituent in PMAA and salen complex. Both electron releasing and electron withdrawing substituents in the substrate and oxidant facilitate the rate of sulfoxidation. Correlation with Hammett constants yields a non-linear concave upward curve. Based on the experimental results and substituent effects two different mechanisms, a direct oxygen atom transfer (DOT) for PMAAs with electron withdrawing substituents and a single electron transfer for PMAAs with electron donating substituents have been postulated.
- Subramaniam,Anbarasan,Sugirtha Devi,Ramdass
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- A paradigm shift in rate determining step from single electron transfer between phenylsulfinylacetic acids and iron(III) polypyridyl complexes to nucleophilic attack of water to the produced sulfoxide radical cation: a non-linear Hammett
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Mechanism of oxidative decarboxylation of phenylsulfinylacetic acids (PSAAs) by iron(III) polypyridyl complexes in aqueous acetonitrile medium has been investigated spectrophotometrically. An initial intermediate formation between PSAA and [Fe(NN)3]3+ is confirmed from the observed Michaelis–Menten kinetics and fractional order dependence on PSAA. Significant rate retardation with concentration of [Fe(NN)3]3+ is rationalized on the basis of coordination of a water molecule at the carbon atom adjacent to the ring nitrogen of the metal polypyridyl complexes by nucleophilic attack at higher concentrations. Electron-withdrawing and electron-releasing substituents in PSAA facilitate the reaction and Hammett correlation gives an upward ‘V’ shaped curve. The apparent upward curvature is rationalized based on the change in the rate determining step from electron transfer to nucleophilic attack, by changing the substituents from electron-releasing to electron-withdrawing groups. Electron-releasing substituents in PSAA accelerate the electron transfer from PSAA to the complex and also stabilize the intermediate through resonance interaction leading to negative reaction constants (ρ). Conversely, electron-withdrawing groups, while retarding the electron transfer exert an accelerating effect on the nucleophilic attack of H2O which leading to low magnitude of ρ+ compared to high ρ? values of electron-releasing groups. Marcus theory is applied, and a fair agreement is seen with the experimental values. Copyright
- Subramaniam, Perumal,Janet Sylvia Jaba Rose, Jebamoney,Jeevi Esther Rathinakumari, Rajasingh
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p. 496 - 504
(2016/09/21)
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- Synthesis and antioxidant activity of bis unsaturated sulfones, bis pyrroles, and bis pyrazoles
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The Michael acceptor 1,4-bis-(E)-2-(arylsulfonylvinyl)benzene was exploited to prepare a new series of bis heterocycles-(1,4-phenylene)bis(arylsulfonylpyrrole) and (1,4-phenylene)bis(arylsulfonyl pyrazole). All of the compounds were tested for antioxidant activity. Amongst the tested compounds, 1,4-bis-(E)-2-(arylsulfonylvinyl)benzene (5) was found to be the best potential antioxidant agent.
- Lavanya,Prakash, T. Bhanu,Sravya,Padmavathi,Padmaja
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p. 8815 - 8828
(2015/10/28)
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- Discovery of 8-cyclopentyl-2-[4-(4-methyl-piperazin-1-yl)-phenylamino]-7- oxo-7,8-dihydro-pyrido[2,3- d ]pyrimidine-6-carbonitrile (7x) as a potent inhibitor of cyclin-dependent kinase 4 (CDK4) and AMPK-related kinase 5 (ARK5)
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The success of imatinib, a BCR-ABL inhibitor for the treatment of chronic myelogenous leukemia, has created a great impetus for the development of additional kinase inhibitors as therapeutic agents. However, the complexity of cancer has led to recent interest in polypharmacological approaches for developing multikinase inhibitors with low toxicity profiles. With this goal in mind, we analyzed more than 150 novel cyano pyridopyrimidine compounds and identified structure-activity relationship trends that can be exploited in the design of potent kinase inhibitors. One compound, 8-cyclopentyl-2-[4-(4-methyl- piperazin-1-yl)-phenylamino]-7-oxo-7,8-dihydro-pyrido[2,3-d]pyrimidine-6- carbonitrile (7x), was found to be the most active, inducing apoptosis of tumor cells at a concentration of approximately 30-100 nM. In vitro kinase profiling revealed that 7x is a multikinase inhibitor with potent inhibitory activity against the CDK4/CYCLIN D1 and ARK5 kinases. Here, we report the synthesis, structure-activity relationship, kinase inhibitory profile, in vitro cytotoxicity, and in vivo tumor regression studies by this lead compound.
- Reddy, M. V. Ramana,Akula, Balireddy,Cosenza, Stephen C.,Athuluridivakar, Saikrishna,Mallireddigari, Muralidhar R.,Pallela, Venkat R.,Billa, Vinay K.,Subbaiah, D. R. C. Venkata,Bharathi, E. Vijaya,Vasquez-Del Carpio, Rodrigo,Padgaonkar, Amol,Baker, Stacey J.,Reddy, E. Premkumar
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p. 578 - 599
(2014/03/21)
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- Spectral and mechanistic investigation of Oxidative Decarboxylation of Phenylsulfinylacetic Acid by Cr(VI)
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The oxidative decarboxylation of phenylsulfinylacetic acid (PSAA) by Cr(VI) in 20% acetonitrile - 80% water (v/v) medium follows overall second order kinetics, first order each with respect to [PSAA] and [Cr(VI)] at constant [H+] and ionic strength. The reaction is acid catalysed, the order with respect to [H+] is unity and the active oxidizing species is found to be HCrO3+. The reaction mechanism involves the rate determining nucleophilic attack of sulfur atom of PSAA on chromium of HCrO3+ forming a sulfonium ion intermediate. The intermediate then undergoes a,β-cleavage leading to the liberation of CO2. The product of the reaction is found to be methyl phenyl sulfone. The operation of substituent effect shows that PSAA containing electron-releasing groups in the meta- and para-positions accelerate the reaction rate while electron withdrawing groups retard the rate. An excellent correlation is found to exist between log k2 and Hammett s constants with a negative value of reaction constant. The p value decreases with increase in temperature evidencing the high reactivity and low selectivity in the case of substituted PSAAs.
- Subramaniam, Perumal,Selvi, Natesan Thamil,Devi, Soundarapandian Sugirtha
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- Inhibition of monoamine oxidase by 8-phenoxymethylcaffeine derivatives
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A recent study has reported that a series of 8-benzyloxycaffeines are potent and reversible inhibitors of both human monoamine oxidase (MAO) isoforms, MAO-A and -B. In an attempt to discover additional caffeine derivatives with potent MAO inhibitory activities, and to contribute to the known structure-activity relationships of MAO inhibition by caffeine derived compounds, the present study investigates the MAO inhibitory potencies of series of 8-phenoxymethylcaffeine and 8-[(phenylsulfanyl)methyl]caffeine derivatives. The results document that the 8-phenoxymethylcaffeine derivatives act as potent reversible inhibitors of MAO-B, with IC50 values ranging from 0.148 to 5.78 μM. In contrast, the 8-[(phenylsulfanyl)methyl]caffeine derivatives were found to be weak inhibitors of MAO-B, with IC50 values ranging from 4.05 to 124 μM. Neither the 8-phenoxymethylcaffeine nor the 8-[(phenylsulfanyl)methyl]caffeine derivatives exhibited high binding affinities for MAO-A. While less potent than the 8-benzyloxycaffeines as MAO-B inhibitors, this study concludes that 8-phenoxymethylcaffeines may act as useful leads for the design of MAO-B selective inhibitors. Such compounds may find application in the therapy of neurodegenerative disorders such as Parkinson's disease. Using molecular docking experiments, this study also proposes possible binding orientations of selected caffeine derivatives in the active sites of MAO-A and -B.
- Okaecwe, Thokozile,Swanepoel, Abraham J.,Petzer, Anél,Bergh, Jacobus J.,Petzer, Jacobus P.
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experimental part
p. 4336 - 4347
(2012/08/28)
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- Derivatives of phenyl tribromomethyl sulfone as novel compounds with potential pesticidal activity
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A halogenmethylsulfonyl moiety is incorporated in numerous active herbicides and fungicides. The synthesis of tribromomethyl phenyl sulfone derivatives as novel potential pesticides is reported. The title sulfone was obtained by following three different synthetic routes, starting from 4-chlorothiophenol or 4-halogenphenyl methyl sulfone. Products of its subsequent nitration were subjected to the SNAr reactions with ammonia, amines, hydrazines and phenolates to give 2-nitroaniline, 2-nitrophenylhydrazine and diphenyl ether derivatives. Reduction of the nitro group of 4-tribromomethylsulfonyl-2- nitroaniline yielded the corresponding o-phenylenediamine substrate for preparation of structurally varied benzimidazoles.
- Borys, Krzysztof M.,Korzynski, Maciej D.,Ochal, Zbigniew
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supporting information; experimental part
p. 259 - 265
(2012/04/18)
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- Identification of anthranilic acid derivatives as a novel class of allosteric inhibitors of hepatitis C NS5B polymerase
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A series of potent anthranilic acid-based inhibitors of the hepatitis C NS5B polymerase has been identified. The inhibitors bind to a site on NS5B between the thumb and palm regions adjacent to the active site as determined by X-ray crystallography of the enzyme-inhibitor complex. Guided by both molecular modeling and traditional SAR, the enzyme activity of the initial hit was improved by approximately 100-fold, yielding a series of potent and selective NS5B inhibitors with IC50 values as low as 10 nM. These compounds were also inhibitors of the HCV replicon in cultured HUH7 cells.
- Nittoli, Thomas,Curran, Kevin,Insaf, Shabana,DiGrandi, Martin,Orlowski, Mark,Chopra, Rajiv,Agarwal, Atul,Howe, Anita Y. M.,Prashad, Amar,Floyd, M. Brawner,Johnson, Bernard,Sutherland, Alan,Wheless, Karen,Feld, Boris,O'Connell, John,Mansour, Tarek S.,Bloom, Jonathan
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p. 2108 - 2116
(2008/02/06)
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- 2-(4-R-Phenoxy/phenylthio)alkanoic esters of l-lupinine
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Considering the great pharmacological interest in phenoxy/phenylthioalkanoic esters of open-chain or cyclic aminoalcohols, a set of ten such esters of lupinine was prepared. Initially, their ability to displace [3H]QNB from rat brain preparation was investigated. With the exception of two, all the prepared esters exhibited good affinity to muscarinic receptors (on a non-selective basis), with pKi in the range 6.67-7.68.
- Sparatore, Anna,Sparatore, Fabio
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p. 169 - 174
(2007/10/03)
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- Selena and thiadiazole fused heterocycles
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The carbonyl group present in benzothiophen-3-ones 4, 3,4- dihydrothiopyrano[3,2-b]benzothiophen-4(2H)-ones 11 and 3,4-dihydro-2H,5H- thiopyrano[2',3' : 4,5]thiopyrano[3,2-b]benzothiophen4-ones 16 has been made use to develop 1,2,3-selena and thiadiazoles via their semicarbazones by the reaction with selenium dioxide and thionyl chloride. The IR, H NMR and C, H analyses has been utilized to characterize the new compounds.
- Padmavathi,Padmaja,Bhaskar Reddy
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p. 308 - 311
(2007/10/03)
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- KINETICS AND MECHANISM OF OXIDATION OF (ARYLTHIO)ACETIC ACIDS BY PYRIDINIUM HYDROBROMIDE PERBROMIDE
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Oxidation of several monosubstituted (phenylthio)acetic acids (PTAA) by pyridinium hydrobromide perbromide (PHPB) was studied in aqueous acetic acid.The reaction is first order with respect to PHPB.Michaelis-Menten type kinetics are observed with respect to (arylthio)acetic acid.The effect of solvent composition indicates that the transition state is more polar than the reactants.The formation constants of the intermediate substrate-PHPB complexes and the rates of their decomposition were determined at different temperatures.The rates of oxidation of para and meta-substituted (phenylthio)acetic acids were correlated with Hammett's substituent constants.The ρ value is -1.60 at 35 deg c.The rates of oxidation of ortho substituted compounds are correlated with Charton's triparametric equation.A mechanism involving the decomposition of the intermediate complex in the slow rate-determining step affording a sulphonium ion which hydrolyses in a subsequent fast step to the sulphoxide is proposed.
- Karunakaran, K.,Elango, K. P.
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p. 429 - 434
(2007/10/02)
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- Photoredox reactions of polypyridyl chromium (III) complexes with arylthioacetic acids in acetonitrile and aqueous media
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The reductive quenching reactions of ,Cr(NN)33+ (NN = 2,2'-bipyridyl, 4,4'-dimethyl-2,2'-bipyridyl and 1,10-phenanthroline) with arylthioacetic acids in acetonitrile and arylthioacetate ions in aqueous media have been studied. The substantial difference in k(q) values between the acetonitrile and aqueous media is traced to the difference in the origin of electron for the reduction of Cr(III) complexes i.e., sulphur in acetonitrile and carboxylate ion in aqueous medium.
- Gnanaraj,Rajagopal,Srinivasan
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p. 9447 - 9456
(2007/10/02)
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- Design, Synthesis, and Testing of Potential Antisickling Agents. 4. Structure-Activity Relationships of Benzyloxy and Phenoxy Acids
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In this paper we further establish the activity of two classes of small molecules, benzyloxy and phenoxy acids, as potent inhibitors of hemoglobin S (HbS) gelation.Structural modifications with a large number of each class confirm our earlier work that the highest activity is observed with compounds that contain dihalogenated aromatic rings with attached polar side chains.We have also found a halogenated aromatic malonic acid derivative to be quite active.Compounds reported in this paper are compared with other antigelling agents studied in our laboratory.Comments are made concerning the antigelling activity and binding sites of four derivatives and their effect on the allosteric mechanism of hemoglobin (Hb) function.
- Abraham, D. J.,Kennedy, P. E.,Mehanna, A. S.,Patwa, D. C.,Williams, F. L.
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p. 967 - 978
(2007/10/02)
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