- Reactions of 4-Nitrophenyl 5-substituted Furan-2-carboxylates with R2NH/R2NH2+ in 20 mol% DMSO(aq): Effect of Aryl Group on the Acyl-Transfer Reaction
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Reactions of 4-nitrophenyl 2-furoates (1a–e) with R2NH/R2NH2+ in 20 mol% DMSO(aq) have been studied. The reactions produced aminolysis products and exhibited second-order kinetics. The Br?nsted plots were linear with βnuc values of 0.75–0.89, which remained nearly the same for all 5-furyl substituents. The rate data showed excellent correlations on the Yukawa-Tsuno plots with ρ(x)?=?0.72–1.1, and r?=?0.55–0.95, respectively. The ρ value increased and r value decreased with a stronger nucleophile, indicating an increase in the electron density at the C-O bond and a decrease in the resonance contribution. The results have been interpreted with the addition–elimination mechanism in which the second step is the rds. By comparing with the data for ArC(O)OC6H4-4-NO2 (Ar?=?Ph, thienyl), the effect of the aryl group on the acyl transfer reaction was assessed.
- Pyun, Sang Yong,Paik, Kyu Cheol,Han, Man So,Cho, Bong Rae
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supporting information
p. 994 - 1000
(2021/05/11)
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- Structure based design, synthesis, and biological evaluation of imidazole derivatives targeting dihydropteroate synthase enzyme
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In this study, we have designed and synthesized 2-((5-acetyl-1-(phenyl)-4-methyl-1H-imidazol-2-yl)thio)-N-(4-((benzyl)oxy)phenyl) acetamide derivatives. Antimicrobial activities of all the imidazole derivatives have been examined against Gram-positive and Gram-negative bacteria and results showed that the conjugates have appreciable antibacterial activity. Besides, several analogous were evaluated for their in vitro antiresistant bacterial strains such as Extended-spectrum beta-lactamases (ESBL), Vancomycin-resistant Enterococcus (VRE), and Methicillin-resistant Staphylococcus aureus (MRSA). The SAR revealed that the 12l compound resulted in potency against all bacterial strains as well as ESBL, VRE, and MRSA strains. Lipinski's rule of five, and ADME studies were preformed for all the synthesized compounds with Staphylococcus aureus dihydropteroate synthase (saDHPS) protein (PDB ID: 6CLV) and were found standard drug-likeness properties of conjugates. Moreover, the binding mode of the ligands with the protein study has been examined by molecular docking and results are quite promising. Besides, all the analogous were tested for their in vitro antituberculosis, antimalarial, and antioxidant activity.
- Daraji, Drashti G.,Rajani, Dhanji P.,Rajani, Smita D.,Pithawala, Edwin A.,Jayanthi, Sivaraman,Patel, Hitesh D.
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supporting information
(2021/02/16)
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- Determination of aromaticity indices of thiophene and furan by nuclear magnetic resonance spectroscopic analysis of their phenyl esters
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A series of m- and p-substituted phenyl benzoates, 2-thienoates, and 2-furoates were prepared and their 1H and 13C nmr spectroscopic characteristics were examined. In general, good correlations were observed between the chemical shift values of protons and carbons of the acyl aromatic rings and the Hammett σ. Plots of the chemical shift values of the carbonyl carbons of the benzoates against those of the 2-thienoates and 2-furoates gave an excellent correlation and the values of the slopes are 0.85 and 0.75, respectively, in dimethyl sulfoxide-d6 and 0.90 and 0.78, respectively, in chloroform-d. The values could be considered as a set of aromaticity indices.
- Lee, Chang Kiu,Yu, Ji Sook,Lee, Hye-Jin
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p. 1207 - 1217
(2007/10/03)
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- Metal Ion Promoted Hydrolysis of p-Nitrophenyl Anthranilates, Glutarate, Salicylate, α-Thiophenate and α-Furoate
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The hydrolysis of 4-nitrophenyl anthranilates, salicylate, glutarate, α-thiophenate and α-furoate at pH 9 is first order in , both in the presence and absence of metal ions.The OH(-) ion is considered the most predominant nucleophile under the conditions of the experiments.Ni(II) and Cu(II) ions enhance the rates of hydrolysis.Enhanced metal ion catalysis is observed with increase in buffer concentration.Hammett rho values for the hydrolysis of 4-nitrophenyl anthranilates are +1.7 and +1.1 in the presence and absence of Ni(II) respectively.The metal forms complexes with the esters and OH(-) ion is considered to attack the ester carbonyl of the complexes.No catalysis is observed with Cu(II), Ni(II) or Zn(II) in the hydrolysis of half-esters of succinic, glutaric and diphenic acids.Intramolecular participation of carboxyl group in the removal of phenoxide is probably inhibited in the presence of metal ion which is coordinated to the carbonyl of ester and acid hydroxyl.Stability of ring formed by the metal ion with these esters is partly responsible for the absence of catalysis.
- Alwar, S. Bangaru Sudarsan,Yesodha, G.,Thiagarajan, V.
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p. 476 - 480
(2007/10/02)
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- Rate enhancement specificity with alpha-chymotrypsin: temperature dependence of deacylation.
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The relative rate of the hydrolysis of 2-(5-n-alkyl)furoyl-alpha-chymotrypsin reaches a maximum with the propyl derivative. The Arrhenius plots for the hydrolyses of the 2-furoyl-, 2-(5-ethyl)furoyl-, and 2-(5-n-propyl)furoyl-alpha-chymotrypsins display a discontinuity, while the plots obtained with the ramaining furoyl derivatives 5-methyl, 5-n-butyl, and 5-n-amyl are linear. We conclude that the deacylation of the furoyl derivatives of alpha-chymotrypsin involves a minimum of two elementary reaction steps. Depending upon the reaction conditions, rate enhancement specificity appears to be either entropy or enthalpy controlled.
- Baggott,Klapper
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p. 1473,1474
(2007/10/07)
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