- Inhibition of copper-mediated aggregation of human γD-crystallin by Schiff bases
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Abstract: Protein aggregation, due to the imbalance in the concentration of Cu2+ and Zn2+ ions is found to be allied with various physiological disorders. Copper is known to promote the oxidative damage of β/γ-crystallins in aged eye lens and causes their aggregation leading to cataract. Therefore, synthesis of a small-molecule ‘chelator’ for Cu2+ with complementary antioxidant effect will find potential applications against aggregation of β/γ-crystallins. In this paper, we have reported the synthesis of different Schiff bases and studied their Cu2+ complexation ability (using UV–Vis, FT-IR and ESI-MS) and antioxidant activity. Further based on their copper complexation efficiency, Schiff bases were used to inhibit Cu2+-mediated aggregation of recombinant human γD-crystallin (HGD) and β/γ-crystallins (isolated from cataractous human eye lens). Among these synthesized molecules, compound 8 at a concentration of 100 μM had shown ~95% inhibition of copper (100?μM)-induced aggregation. Compound 8 also showed a positive cooperative effect at a concentration of 5–15 μM on the inhibitory activity of human αA-crystallin (HAA) during Cu2+-induced aggregation of HGD. It eventually inhibited the aggregation process by additional ~20%. However, ~50% inhibition of copper-mediated aggregation of β/γ-crystallins (isolated from cataractous human eye lens) was recorded by compound 8 (100 μM). Although the reductive aminated products of the imines showed better antioxidant activity due to their lower copper complexing ability, they were found to be non-effective against Cu2+-mediated aggregation of HGD. Graphical Abstract: [Figure not available: see fulltext.]
- Chauhan, Priyanka,Muralidharan, Sai Brinda,Velappan, Anand Babu,Datta, Dhrubajyoti,Pratihar, Sanjay,Debnath, Joy,Ghosh, Kalyan Sundar
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p. 505 - 517
(2017/06/05)
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- A Biphilic Phosphetane Catalyzes N-N Bond-Forming Cadogan Heterocyclization via PIII/PV = O Redox Cycling
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A small-ring phosphacycle, 1,2,2,3,4,4-hexamethylphosphetane, is found to catalyze deoxygenative N-N bond-forming Cadogan heterocyclization of o-nitrobenzaldimines, o-nitroazobenzenes, and related substrates in the presence of hydrosilane terminal reductant. The reaction provides a chemoselective catalytic synthesis of 2H-indazoles, 2H-benzotriazoles, and related fused heterocyclic systems with good functional group compatibility. On the basis of both stoichiometric and catalytic mechanistic experiments, the reaction is proposed to proceed via catalytic PIII/PV = O cycling, where DFT modeling suggests a turnover-limiting (3+1) cheletropic addition between the phosphetane catalyst and nitroarene substrate. Strain/distortion analysis of the (3+1) transition structure highlights the controlling role of frontier orbital effects underpinning the catalytic performance of the phosphetane.
- Nykaza, Trevor V.,Harrison, Tyler S.,Ghosh, Avipsa,Putnik, Rachel A.,Radosevich, Alexander T.
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supporting information
p. 6839 - 6842
(2017/05/29)
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- Catalyst-free allylation of 2-aminophenol–derived aldimines with allyltrichlorosilane under thermal conditions
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Allylation of 2-aminophenol-derived aldimines using allyltrichlorosilane under catalyst free conditions has been developed. This reaction afforded the corresponding homoallylic amines in good to excellent yields (68–94%). The salicylaldehyde-derived aldimines as well as benzoylhydrazone also found to react with allyltrichlorosilane smoothly under the same conditions, to furnish the corresponding homoallylic amine derivatives. This study suggests that the phenolic –OH group acts as an anchoring group for the transfer of allyl group from allyl silane reagent.
- Venkatanna, Kesa,Ramanathan, Chinnasamy Ramaraj
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supporting information
p. 3650 - 3653
(2017/08/22)
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- Single Heteroatom Fine-Tuning of the Emissive Properties in Organoboron Complexes with 7-(Azaheteroaryl)indole Systems
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The application of organoboron compounds as light-absorbing or light-emitting species in areas as relevant as organic electronics or biomedicine has motivated the search for new materials which contribute to the progress of those applications. This articl
- Más-Montoya, Miriam,Usea, Laura,Espinosa Ferao, Arturo,Montenegro, María F.,Ramírez De Arellano, Carmen,Tárraga, Alberto,Rodríguez-López, José N.,Curiel, David
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p. 3296 - 3302
(2016/05/19)
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- Synthesis and biological activities of 2-aminophenol-based Schiff bases and their structure-activity relationship
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Six Schiff bases 8-13 were synthesized by condensation of 2-aminophenol (1) with various chloro- and nitro-benzaldehydes (2-7), characterized, and evaluated for antioxidant, antibacterial, lipoxygenase, and urease inhibitory potentials. All Schiff bases e
- Aslam, Muhammad,Anis, Itrat,Mehmood, Rashad,Iqbal, Lubna,Iqbal, Samina,Khan, Inamullah,Chishti, Muhammad Salman,Perveen, Shagufta
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p. 109 - 115
(2016/01/25)
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- Binding multidentate ligands to Ni2+: Kinetic identification of preferential binding sites
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The kinetics of the reactions between [Ni(MeOH)6]2+ (hereafter Ni2+) and a variety of neutral Schiff base multidentate ligands have been measured in methanol at 25.0°C using stopped-flow spectrophotometry. The ligands cont
- Nartop, Dilek,Clegg, William,Harrington, Ross W.,Henderson, Richard A.,Wills, Corinne Y.
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p. 3372 - 3382
(2014/03/21)
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- A new and efficient one-pot synthesis of 2-hydroxy-1,4-dihydrobenzoxazines via a three-component Petasis reaction
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The secondary amines synthesized by the reaction between 2-aminophenols and aromatic aldehydes, via the reduction of the corresponding imines, were employed in the synthesis of new 2-hydroxy-2H-1,4-benzoxazine derivatives through a one-pot Petasis multico
- Chouguiat, Louisa,Boulcina, Raouf,Carboni, Bertrand,Demonceau, Albert,Debache, Abdelmadjid
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supporting information
p. 5124 - 5128
(2014/12/10)
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- Ni nanoparticles: Mild and efficient catalyst for the chemoselective synthesis of 2-arylbenzimidazoles, 2-arylbenzothiazoles, and azomethines
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(Chemical Equation Presented) A new and efficient method has been developed for the synthesis of biologically significant 2-arylbenzimidazoles, 2-arylbenzothiazoles, and azomethines using recyclable and inexpensive polyvinyl pyrrolidone (PVP)-stabilized Ni nanoparticles in ethylene glycol at room temperature in excellent yields. Copyright Taylor & Francis Group, LLC.
- Khurana, Jitender M.,Sneha,Vij, Kanika
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experimental part
p. 2606 - 2616
(2012/08/08)
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- 2-Arylbenzothiazole, benzoxazole and benzimidazole derivatives as fluorogenic substrates for the detection of nitroreductase and aminopeptidase activity in clinically important bacteria
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A series of 2-(2-nitrophenyl)benzothiazole 7, 2-(2-nitrophenyl)benzoxazole 10 and 2-(2-nitrophenyl)benzimidazole 13 derivatives have been synthesised and assessed as indicators of nitroreductase activity across a range of clinically important Gram negativ
- Cellier, Marie,Fabrega, Olivier J.,Fazackerley, Elizabeth,James, Arthur L.,Orenga, Sylvain,Perry, John D.,Salwatura, Vindhya L.,Stanforth, Stephen P.
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experimental part
p. 2903 - 2910
(2011/06/21)
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