19081-19-7Relevant articles and documents
New piperidine-hydrazone derivatives: Synthesis, biological evaluations and molecular docking studies as AChE and BChE inhibitors
Karaman, Nurcan,S?cak, Yusuf,Ta?k?n-Tok, Tu?ba,?ztürk, Mehmet,Karakü?ük-?yido?an, Ay?egül,Dikmen, Miris,Ko?yi?it-Kaymak??o?lu, Bedia,Oru?-Emre, Emine El?in
, p. 270 - 283 (2016/09/09)
Hydrazones and the piperidine ring containing compounds were considered as beneficial substrates in drug design. Therefore, this study was aimed at the synthesis of new benzoyl hydrazones derived from ethyl 4-oxopiperidine-1-carboxylate and 2,6-diphenylpiperidin-4-one. The synthesized compounds (1?19) were screened for their antioxidant, anticholinesterase and anticancer activities. The antioxidant capacity of the compounds was evaluated by using four complementary tests. The results showed that compound 7 and 17 have the higher lipid peroxidation inhibitory activity than the other compounds. In DPPH˙ scavenging assay, compounds 5, 6, 10, 14, 17 demonstrated better activity than that of standard BHT, while in ABTS+˙ scavenging assay compound 6 and 17 exhibited better activity among the other compounds. The CUPRAC assay disclosed that compound 2 displayed better activity than α-tocopherol. The anticholinesterase activity was performed against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. Compound 11 (IC50: 35.30?±?1.11?μM) inhibited BChE better than galantamine (IC50: 46.03?±?0.14?μM). We conclude that the compound 11 can be considered as a candidate for BChE inhibitor. Moreover docking method was applied to elucidate the AChE and BChE inhibitory mechanism of the compound 11. Molecular docking analysis revealed that compound 11 bound to BChE enzyme more efficiently when compared to the AChE due to its orientations and different types of interactions. In addition, the non-cytotoxic properties of the compounds brought them into prominence, although they did not show significant anticancer properties.
Nucleophilic displacement at the benzoyl centre: A study of the change in geometry at the carbonyl carbon atom
Colthurst, Matthew J.,Williams, Andrew
, p. 1493 - 1497 (2007/10/03)
The second-order rate constants for the reaction between hydroxide ion and phenoxide ion with 4-nitrophenyl esters of substituted benzoic acids in 10% acetonitrile-water (v/v) solution obey Hammett σ correlations. The values of the Hammett ρ of 1.67 (κArO) and 2.14 (κOH) are consistent with a large change in hybridization at the central carbon by comparison with the ρ value for a standard reaction where a full sp2 to sp3 change occurs. The transition state for the concerted reaction thus has a substantially tetrahedral geometry. The observation of the anti-Hammond effect whereby the ρ value for the hydroxide ion exceeds that of the less reactive phenoxide ion is consistent with a concerted, ANDN, mechanism for these reactions. A stepwise mechanism, AN + DN, is unlikely to yield a measurable break in the Hammett correlation for a change in the benzoyl substituent if the partitioning of the putative tetrahedral intermediate involves forward and reverse reactions with Hammett correlations possessing similar ρ values.
Imidazole-Catalyzed Hydrolysis of Substituted Benzoate Esters. A Detailed Kinetic and Mechanistic Study
Menegheli, Paulo,Farah, Joao P. S.,Seoud, Omar A. El
, p. 1610 - 1615 (2007/10/02)
Kinetic and mechanistic details of the imidazole-catalyzed hydrolysis of substituted phenyl benzoates in 10percent acetonitrile in water (V/V) were examined.The following 4 ester series were studied: p-nitrophenyl p-X-benzoates (X = CH3, H, Cl, CN, NO2, series I), p-Y-phenyl p-nitrobenzoates (Y = CH3, H, Cl, CN, NO2, series II), 2,4-dinitrophenyl p-X-benzoates (X = CH3O, H, Cl, CN, NO2, series III) and p-Y-phenyl 2,4-dinitrobenzoates (Y = CH3, H, Cl, CN, NO2, series IV).Based on: catalytic rate constants, activation parameters, kinetic solvent isotope effects, Hammett (ρ) values and the spectroscopic detection of the reaction intermediates, the following conclusions were reached: a) imidazole acts as a nucleophilic catalyst, i.e., the hydrolysis occurs via the intermediate formation of acylimidazole; b) the leaving group is the phenoxide ion; c) the rate limiting step is the decomposition of the tetrahedral intermediate that precedes the acylimidazole (series I, II and IV) or the attack of imidazole on the acyl group of the ester (series III). Keywords: Acylimidazoles / Catalysis / Chemical Kinetics / Isotope Effects / Reaction Mechanism
