- Green synthesis of Ag@Au bimetallic regenerated cellulose nanofibers for catalytic applications
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The green synthesis of nanocomposites has attracted huge consideration in recent years due to its positive environmentally friendly impact. The present study reports the first bimetallic Ag-Au cellulose nanofiber composite (Ag@Au/CNCs) prepared via a very simple green preparation method. An aqueous leaves extract of Moringa oleifera was used to obtain the bimetallic Ag@Au/CNC nanocomposite. High-resolution transmission electron microscopy (HRTEM) observations revealed the successful formation of triangle, hexagonal, and spherical shapes of well-combined Ag-Au nanoparticles on the regenerated cellulose nanofiber surface. Further, the formation of Au-Ag bimetallic nanostructures was confirmed by X-ray photoelectron spectroscopy (XPS) and X-ray crystallography (XRD) results. The resultant bimetallic Ag@Au/CNC catalyst was found to perform remarkably well in the reduction of nitrophenols. The bimetallic Ag@Au/CNC catalyst gave excellent kapp values of 15.59 and 22.83 × 10-3 s-1 for the 2- A nd 4-nitrophenol reduction process, respectively. To our delight, the Ag@Au/CNC catalyst was found to perform well in the aza-Michael reaction. The catalytic activity of Ag@Au/CNCs was compared with mono-metallic Ag/CNCs, Au/CNCs, and other reported catalysts. Based on the results obtained, the high synergy of Ag@Au/CNCs was explained. A possible mechanism is proposed for the Ag@Au/CNC-catalyzed nitrophenol reduction and aza-Michael reactions.
- Gopiraman, Mayakrishnan,Saravanamoorthy, Somasundaram,Baskar, Ramaganthan,Ilangovan, Andivelu,Ill-Min, Chung
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p. 17090 - 17103
(2019/11/14)
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- Cultivation of a Cu/HMPC catalyst from a hyperaccumulating mustard plant for highly efficient and selective coupling reactions under mild conditions
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Cu-containing activated carbon (eco-catalyst, Cu/HMPC, where 'C' defines 'carbon') was derived from a metal-hyperaccumulating mustard plant (HMP) by a simple chemical activation method. Transmission electron microscopy/selected area diffraction (HRTEM/SAED) results revealed that the Cu/HMPC has mainly three types of morphology [sheet-like morphology (2D), hollow-spheres (3D) and needle-like structures (1D)] which are interconnected. HRTEM-SAED, Raman and X-ray photoelectron spectroscopy (XPS) results confirmed the existence of Cu oxide species in Cu/HMPC. Content of Cu in Cu/HMPC was determined to be 1.03 wt%. The quality of graphitization in Cu/HMPC was discussed by using Raman and XRD results. The BET surface area of Cu/HMPC was determined to be 620.8 m2 g-1. The Cu/HMPC actively transformed a wide range of amines to imines under very mild reaction conditions. The catalyst Cu/HMPC gave products in excellent yields (98-61%) with very high TON/TOF values (1512/339-833/35 h-1). To the best of our knowledge, this is the most efficient Cu-based heterogeneous eco-catalyst for the synthesis of imines among those reported to date. The Cu can be recovered from used Cu/HMPC by a simple HCl treatment. Versatility, heterogeneity and reusability of Cu/HMPC were tested. A possible mechanism has been proposed.
- Gopiraman, Mayakrishnan,Wei, Kai,Zhang, Ke-Qin,Chung, Ill-Min,Kim, Ick Soo
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p. 4531 - 4547
(2018/02/09)
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- 3-PHOSPHOGLYCERATE DEHYDROGENASE INHIBITORS AND USES THEREOF
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The present invention provides compounds, compositions thereof, and methods of using the same.
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- Convergent synthesis of polynitrile and/or polyamine dendrimers through hydroaminomethylation and Michael addition
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A general concept for a versatile convergent synthesis ofpolynitrile and/or polyamine dendrimers has been developed by applying Voegtle's procedure in combination with thetandem hydroformylation/reductive amination sequence, known as hydroaminomethylation
- Beigi, Maryam,Ricken, Stefan,Mueller, Kai Sven,Koc, Fikret,Eilbracht, Peter
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supporting information; experimental part
p. 1482 - 1492
(2011/04/22)
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- Synthesis of dendritic tryptophan derivatives and investigation on dendritic effects of their fluorescence and reactivity
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Two series of dendritic tryptophan derivatives have been synthesized and characterized, their emission spectra in different solvents and the reactivity of tryptophan were investigated and compared. There was a progressive shielding effect of the tryptophan in the emissive wavelengths of dendrimers increased with the size or generation of the dendritic shell.
- He, Dongsheng,He, Gu,Guo, Li
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scheme or table
p. 454 - 460
(2012/04/10)
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- Unsymmetrical cyclotriazadisulfonamide (CADA) compounds as human CD4 receptor down-modulating agents
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Cyclotriazadisulfonamide (CADA) inhibits HIV at submicromolar levels by specifically down-modulating cell-surface and intracellular CD4. The specific biomolecular target of CADA compounds is unknown, but previous studies led to an unsymmetrical binding model. To test this model, methods were developed for effective synthesis of diverse, unsymmetrical CADA compounds. A total of 13 new, unsymmetrical target compounds were synthesized, as well as one symmetrical analogue. The new compounds display a wide range of potency for CD4 down-modulation in CHO-CD4-YFP cells. VGD020 (IC50 = 46 nM) is the most potent CADA compound discovered to date, and VGD029 (IC50 = 730 nM) is the most potent fluorescent analogue. Structure-activity relationships are analyzed from the standpoint of additive or nonadditive energy effects of different substituents. They appear to be consistent with the zipper-type mechanism in which entropy costs are reduced for additional stabilizing interactions between the small molecule and its protein target.
- Demillo, Violeta G.,Goulinet-Mateo, Florian,Kim, Jessica,Schols, Dominique,Vermeire, Kurt,Bell, Thomas W.
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scheme or table
p. 5712 - 5721
(2011/10/08)
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- An effective aza-michael addition of aromatic amines to electron-deficient alkenes in alkaline Al2O3
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Aza-Michael addition of aromatic or aliphatic amines with various electron-deficient alkenes was performed using alkaline Al2O 3 as solid media at room temperature afforded the corresponding Michael addition products in good to excellent yields.The alkaline Al 2O3 can be easily recovered and reused.
- Ai, Xin,Wang, Xin,Liu, Jin-Ming,Ge, Ze-Mei,Cheng, Tie-Ming,Li, Run-Tao
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experimental part
p. 5373 - 5377
(2010/08/06)
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- Aqueous aza-michael reaction of conjugated alkenes: Toward spermine
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An aqueous aza-Michael reaction is efficiently achieved with excellent conversions without any additives. The method works very well on a molar scale with selectively for aliphatic amines. An intermediate for spermine is also made by this green process.
- Joshi, Jigar H.,Saiyed, Akeel S.,Bedekar, Ashutosh V.
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experimental part
p. 2857 - 2863
(2010/11/18)
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- POLYAMINE DERIVATIVE AND POLYOL DERIVATIVE
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A novel polyamine derivative, or polyol derivative, having a piperidylaminotriazine skeleton, salts of such compounds, a process for producing them, an organic material stabilizer comprising any of such compounds, a method of stabilizing an organic materi
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Page/Page column 33
(2008/06/13)
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- Cellulose-supported copper(0) catalyst for aza-Michael addition
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Cellulose-supported copper(0) efficiently catalyzes the aza-Michael reaction of N-nucleophiles, such as amines and imidazoles with α,β-unsaturated compounds to produce the corresponding β-amino compounds and N-substituted imidazoles in excellent yields. The reactions are facile and the recovered catalyst is used for several cycles with consistent activity. Georg Thieme Verlag Stuttgart.
- Reddy, K. Rajender,Kumar, Nadakudity S.
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p. 2246 - 2250
(2007/10/03)
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- Synthesis and structure-activity relationship studies of CD4 down-modulating cyclotriazadisulfonamide (CADA) analogues
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HIV attachment via the CD4 receptor is an important target for developing novel approaches to HIV chemotherapy. Cyclotriazadisulfonamide (CADA) inhibits HIV at submicromolar levels by specifically down-modulating cell-surface and intracellular CD4. An effective five-step synthesis of CADA in 30% overall yield is reported. This synthesis has also been modified to produce more than 50 analogues. Many tail-group analogues have been made by removing the benzyl tail of CADA and replacing it with various alkyl, acyl, alkoxycarbonyl and aminocarbonyl substituents. A series of sidearm analogues, including two unsymmetrical compounds, have also been prepared by modifying the CADA synthesis, replacing the toluenesulfonyl sidearms with other sulfonyl groups. Testing 30 of these compounds in MT-4 cells shows a wide range of CD4 down-modulation potency, which correlates with ability to inhibit HIV-1. Three-dimensional quantitative structure-activity relationship (3D-QSAR) models were constructed using comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) approaches. The X-ray crystal structures of four compounds, including CADA, show the same major conformation of the central 12-membered ring. The solid-state structure of CADA was energy minimized and used to generate the remaining 29 structures, which were similarly minimized and aligned to produce the 3D-QSAR models. Both models indicate that steric bulk of the tail group, and, to a lesser extent, the sidearms mainly determine CD4 down-modulation potency in this series of compounds.
- Bell, Thomas W.,Anugu, Sreenivasa,Bailey, Patrick,Catalano, Vincent J.,Dey, Kaka,Drew, Michael G. B.,Duffy, Noah H.,Jin, Qi,Samala, Meinrado F.,Sodoma, Andrej,Welch, William H.,Schols, Dominique,Vermeire, Kurt
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p. 1291 - 1312
(2007/10/03)
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- A green, ionic liquid and quaternary ammonium salt-catalyzed aza-Michael reaction of α,β-ethylenic compounds with amines in water
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The first environmentally benign, highly efficient conjugate addition of aliphatic amines to α,β-unsaturated compounds catalysed by simple quaternary ammonium salts and ionic liquids in the green solvent, water, is described.
- Xu, Li-Wen,Li, Jing-Wei,Zhou, Shao-Lin,Xia, Chun-Gu
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p. 183 - 184
(2007/10/03)
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- Aza-Michael Reactions in Ionic Liquids. A Facile Synthesis of β-Amino Compounds
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Electron-deficient olefins undergo smoothly aza-Michael reactions with a wide range of amines in ionic liquids in the absence of any acid catalyst to produce the corresponding β-amino compounds in excellent yields with high 1,4-selectivity. The recovered ionic liquids can be reused in subsequent reactions without loss of activity. Owing to the high polarity of ionic liquids, the enones show enhanced reactivity thereby reducing reaction times and improving the yields significantly.
- Yadav,Reddy,Basak,Narsaiah
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p. 988 - 989
(2007/10/03)
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- Chemoselective Michael type addition of aliphatic amines to α,β-ethylenic compounds using bismuth triflate catalyst
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Catalytic amounts of bismuth triflate efficiently catalyse the conjugate addition of aliphatic amines to α,β-ethylenic compounds in acetonitrile under mild conditions. The reaction is chemoselective, as aromatic amines do not participate in the reaction. Further, the catalyst can be easily recovered and reused.
- Varala, Ravi,Alam, M. Mujahid,Adapa, Srinivas R.
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p. 720 - 722
(2007/10/03)
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- Syntheses, conformations, and basicities of bicyclic triamines
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The multistep syntheses of several bicyclic triamines are described, all of which have an imbedded 1,5,9-triazacyclododecane ring. In 1,5,9-triazabicyclo[7.3.3]pentadecanes 12, 13, 15, and 16, two nitrogens are bridged by three carbons. The monoprotonated forms of these triamines are highly stabilized by a hydrogen-bonded network involving the bridge and both bridgehead nitrogens, producing a difference of more than 8 pKa units in acidities of their monoprotonated and diprotonated forms. The one- and zero-carbon bridges in 1,5,9-triazabicyclo[9.1.1]tridecane (23) and 7-methyl-1,5,9-triazabicyclo[5.5.0]dodecane (39) do not enhance the stabilities of their monoprotonated forms. X-ray crystal structures and computational studies of 12·HI and 16·HI reveal similar, but somewhat weaker, hydrogen-bonded networks, relative to 15·HI. The activation free energies for conformational inversion of 13·HI (14.4 ± 0.2 kcal/mol), 16·HI (15.0 ± 0.1 kcal/mol) and 16 (8.8 ± 0.3 kcal/mol) were measured by variable-temperature 1H and 13C NMR spectroscopy. These experimental barriers give an estimate of 6.2 kcal/mol for the strength of the bifurcated hydrogen bond between the bridge nitrogen and cavity proton in 16·HI. Computational studies support the hypothesis that N-inversion occurs in an open conformation, leading to an estimate of 10.32 kcal/mol for the enthalpy of the bifurcated hydrogen bond in 16·HI in the gas phase.
- Bell, Thomas W.,Choi, Heung-Jin,Harte, William,Drew, Michael G. B.
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p. 12196 - 12210
(2007/10/03)
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- Anti-viral triaza compounds and compositions
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The invention relates to a family of new synthetic triamine compounds which can be used in antiviral pharmaceutical compositions.
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Page column 7
(2010/01/30)
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- Indium trichloride-catalyzed conjugate addition of amines to α,β-ethylenic compounds in water
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Catalytic amount of indium (III) trichloride efficiently catalyzed Michael reaction between amines and α,β-ethylenic compounds in water and under mild conditions. Indium trichloride can be recovered and reused without decrease in yield.
- Loh, Teck-Peng,Wei, Lin-Li
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p. 975 - 976
(2007/10/03)
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- Anxiolytic properties of certain annelated [1,2,3]triazolo[1,5-c]pyrimidin-5(6H)-ones
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Modification of the benzodiazepine (BZ) receptor binding template 2-aryl[1,2,4]triazolo[1,5-c]quinazolin-5(6H)-one by replacement of the annelated benzene ring with various alicyclic and heterocyclic moieties led to novel structures with potent BZ receptor binding affinity. High affinity was found in some cycloalkyl-annelated [1,2,4]triazolo[1,5-c]pyrimidin-5(6H)-ones and in some 7,8,9,10-tetrahydropyrido[3,4-e][1,2,4]triazolo[1,5-c] pyrimidin-5(6H)-ones, in which the degree of activity was strongly dependent on the N-substituent in the 9-position. Nine compounds with BZ receptor IC50 binding affinity values equal or superior to diazepam were evaluated in secondary screening. One of these, 9-benzyl-2-phenyl-7,8,9,10-tetrahydropyrido[3,4-e] [1,2,4]triazolo[1,5-c]pyrimidin-5(6H)-one, showed good activity in rats as a potential anxiolytic agent without sedative liability. However, it increased the rotorod deficit produced by ethanol at anxiolytic doses, an indication of alcohol interaction. Thus, none of the compounds showed an advantage over CGS 9896 (Yokoyama et al. J. Med. Chem. 1982, 25, 337-339), which is free of sedative and alcohol interaction potential as measured by the test procedures described.
- Francis,Bennett,Hyun,Rovinski,Amrick,Loo,Murphy,Neale,Wilson
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p. 2899 - 2906
(2007/10/02)
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- Methods and intermediates for the preparation of spermidine, homospermidine and norspermidine
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Novel azadinitriles and a method for their hydrogenation to produce spermidine, homospermidine and norspermidine.
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