- Triarylmethyl Cation-Catalyzed Three-Component Coupling for the Synthesis of Unsymmetrical Bisindolylmethanes
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An efficient synthesis of unsymmetrical bisindolylmethanes has been accomplished using triarylmethyl cations to catalyze the reaction of N-arylimines with two different indoles. Optimization of the organocatalyst by tuning cation stability allows for excellent single addition selectivity when coupled with p-nitrophenyl imines. The optimal catalyst is commercially available, and the reaction minimizes waste and environmental impact by employing a one-to-one ratio of starting materials. The intermediates can be isolated or used in situ in a one-pot two-step reaction to generate unsymmetrical bisindolylmethanes in high yields. The reaction tolerates a broad range of imines with the highest yields observed for electron-poor and neutral imines. A wide range of indole nucleophiles are also successfully employed allowing for the creation of a large variety of unsymmetrical bisindolylmethanes.
- Bardelski, Kevin,Brindle, Cheyenne S.,Chen, Zhenghua,Guarino-Hotz, Melissa,Jones, Vanessa A.,Lucas, Kelly,Patterson, William J.
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supporting information
p. 6737 - 6742
(2021/12/31)
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- Observation of the complex spectra for the supramolecular system involving silver nanoparticles-biaryl Schiff bases containing the nitro group
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A series of biaryl Schiff bases containing the nitro groups, 4-XArCH═NArNO2-4′ (XBANO2-4′) and 4-NO2ArCH═NArY-4′ (4-NO2BAY), were synthesized. Also, the fish sperm DNA (fsDNA) and silver nanoparticles (AgNPs) solutions were prepared. By mixing these compounds with fsDNA or AgNPs solution and determining the ultraviolet absorption spectra of the mixture solutions, an interesting phenomenon was found: a new absorption peak λmax,lim appeared in the (XBANO2-4′)-AgNPs solution, which was longer than the wavelength of λmax of XBANO2-4′ solution. The new absorption peak in the (XBANO2-4′)-AgNPs solution was the complex spectrum originating from the electron transfer between XBANO2-4′ and AgNPs. Whereas this phenomenon was not observed in the (4-NO2BAY)-AgNPs solutions, a quantitative correlation analysis was carried out with the measured spectral data, and the results show that the wave number νmax,lim of the λmax,lim is mainly affected by the excited-state substituent constant (Formula presented.) rather than the ground Hammett constant σ of the X group. The redshift magnitude Δνmax,WSL, namely, Δνmax,WSL = (1/λmax) ? (1/λmax,lim), of the wavelength λmax,lim is related to the highest occupied molecular orbital and lowest unoccupied molecular orbital of XBANO2-4′. The discovery of this new phenomenon is helpful to understanding the interaction between AgNPs-organic compound supramolecular systems.
- Cao, Chao-Tun,Cheng, Shi-Mao,Cao, Chenzhong
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- Dual Heterogeneous Catalyst Pd-Au@Mn(II)-MOF for One-Pot Tandem Synthesis of Imines from Alcohols and Amines
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A new Mn(II) metal-organic framework (MOF) 1 was synthesized by the combination of 4,4,4-trifluoro-1-(4-(pyridin-4-yl)phenyl)butane-1,3-dione (L) and Mn(OAc)2 in solution. 1 features a threefold-interpenetrating NbO net containing honeycomb-like channels, in which the opposite Mn(II)···Mn(II) distance is 23.5075(10) ?. Furthermore, 1 can be an ideal platform to support Pd-Au bimetallic alloy nanoparticles to generate a composite catalytic system of Pd-Au@Mn(II)-MOF (2). 2 can be a highly active bifunctional heterogeneous catalyst for the one-pot tandem synthesis of imines from benzyl alcohols and anilines and from benzyl alcohols and benzylamines.
- Chen, Gong-Jun,Ma, Hui-Chao,Xin, Wen-Ling,Li, Xiao-Bo,Jin, Fa-Zheng,Wang, Jing-Si,Liu, Ming-Yang,Dong, Yu-Bin
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supporting information
p. 654 - 660
(2017/01/13)
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- A general aminocatalytic method for the synthesis of aldimines
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A general and efficient biomimetic method for the synthesis of aldimines from aldehydes and compounds bearing the NH2 group in the presence of pyrrolidine as a catalyst has been developed. These organocatalytic reactions, based on the application of the concept of nucleophilic catalysis, proceed with outstanding yields in the absence of acids and metals under simple conditions and minimum experimental manipulation. The method has been mainly applied to the synthesis of N-sulfinyl and N-sulfonyl imines, but its general validity has been proven with the preparation of representative N-phosphinoyl, N-alkyl, and N-aryl imines. These unprecedented reactions, which presumably occur via iminium activation without requiring acidic conditions, are an interesting and competitive alternative to the classical methods for preparing aldimines.
- Morales, Sara,Guijarro, Fernando G.,Garcia Ruano, Jose Luis,Cid, M. Belen
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supporting information
p. 1082 - 1089
(2014/02/14)
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- One pot photoredox decarboxylation reaction of N-cyano(α-bromo- α-phenyl)methylanilines leading to synthesis of four-membered cyclic carbamates
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A new four-membered cyclic carbamates have been synthesized through solar irradiation of N-cyano(α-bromo-α-phenyl)methylanilines in their aqueous methanolic solution using iodide salt in basic medium. These compounds have been characterized as 3,4-diphenyl-1,3oxazetidin-2-one through their elemental analysis, IR, 1H-NMR, 13C-NMR, and mass spectral studies.
- Kaur, Manpreet,Singh, Baldev
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p. 850 - 853
(2014/06/10)
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- Nano-tube TiO2 as a new catalyst for eco-friendly synthesis of imines in sunlight
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Nanomaterials are considered as suitable heterogeneous catalysts for many organic reactions. Herein nano-tube TiO2 has been reported as a heterogeneous catalyst, for synthesis of imines in sunlight at room temperature under solvent-free conditions. The condensation of less electrophilic carbonyl compounds with poorly nucleophilic amines was afforded imines in excellent yields.
- Hosseini-Sarvari, Mona
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experimental part
p. 547 - 550
(2012/01/06)
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- 2,3-dihydro-1,2-diphenyl-substituted 4H-pyridinone derivatives as new anti flaviviridae inhibitors
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With the aim of identifying novel lead compounds active against emergent human infectious diseases, a series of 2,3-dihydro-4H-pyridinone derivatives has been prepared and evaluated for antiviral activity. Compounds were evaluated in vitro in cell-based assays for cytotoxicity and against a wide spectrum of viruses. In the antiviral screening, several compounds showed to be fairly active against viruses belonging to the Flaviviridae family. The Pestiviruses (bovine viral diarrhoea virus) were inhibited by 4acis (CC50>100μm; EC50 = 14μm), compounds 4ccis and 6a showed a significant activity against Flaviviruses (Yellow Fever Virus) (CC50>100μm; EC50=18μm, CC50>100μm; EC50=10μm). Among these, compound 6a displayed great inhibitory activity against Hepaciviruses (hepatitis C virus) in replicon assay [CC50 > 100μm; EC50(1b)=4μm]. In vitro inhibitory activity against the HCV RNA-dependent RNA polymerase (NS5B) of title compounds is discussed. The antiviral screening of viral strains indicated that compound 6a can be selected as promising tool in novel anti-flaviviruses development.
- Peduto, Antonella,Massa, Antonio,Di Mola, Antonia,de Caprariis, Paolo,La Colla, Paolo,Loddo, Roberta,Altamura, Sergio,Maga, Giovanni,Filosa, Rosanna
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experimental part
p. 441 - 449
(2012/01/13)
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- Aqueous extract of the pericarp of Sapindus trifoliatus fruits: A novel 'green' catalyst for the aldimine synthesis
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The catalytic efficiency in organic synthesis of the aqueous extract of the pericarp of Sapindus trifoliatus fruits was evaluated. The synthesis of a series of aldimines from aromatic aldehydes and amines was successfully catalyzed by the extract, whereas aromatic ketones and amines did not yield ketimines under comparable reaction conditions, indicating the chemoselective catalysis of the extract. The catalytic activity of the extract is due to saponins, which have a common structural skeleton containing a pentacyclic triterpenoid part substituted with different carbohydrate side chains. The mild conditions, high yields, and short reaction times not only make this protocol a valuable alternative to the conventional methods, but it also becomes significant under the roof of environmentally greener and safer processes.
- Pore, Santosh,Rashinkar, Gajanan,Mote, Kavita,Salunkhe, Rajeshri
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experimental part
p. 1796 - 1800
(2011/08/05)
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- Oxidation and deprotection of primary benzylamines by visible light flavin photocatalysis
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We report a photocatalytic oxidation procedure that can be used to convert benzylamines into their corresponding aldehydes under mild conditions without over-oxidation, using riboflavin tetraacetate as photocatalyst and blue emitting LEDs (440 nm) as light source. Oxygen is the terminal oxidant and H 2O2 and NH3 appear as the only byproducts of the oxidation of primary benzylamines. Furthermore, we have developed a photocatalytic protocol for 4-methoxybenzyl (Mob) group deprotection of primary amines and alcohols. Double bonds, benzyl-protected esters and alcohols are tolerated under the applied conditions, whereas the deprotection of protected secondary amines is not applicable. Mob-protected carboxylic acids and carboxybenzoyl (Cbz) protected amines are inert under the photodeprotection conditions. Georg Thieme Verlag Stuttgart - New York.
- Lechner, Robert,Koenig, Burkhard
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experimental part
p. 1712 - 1718
(2010/07/05)
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- Substituent cross-interaction effects on the electronic character of the C=N bridging group in substituted benzylidene anilines - Models for molecular cores of mesogenic compounds. A 13C NMR study and comparison with theoretical results
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13C NMR chemical shifts δc(C=N) were measured in CDCl 3 for a wide set of mesogenic molecule model compounds, viz. the substituted benzylidene anilines P-X-C6H4CH=NC 6H4-p-Y (X = NO2, CN, CF3, F, Cl, H, Me, MeO, or NMe2; Y = NO2, CN, F, Cl, H, Me, MeO, or NMe2). The substituent dependence of δc(C=N) was used as a tool to study electronic substituent effects on the azomethine unit. The benzylidene substituents X have a reverse effect on δc(C=N): electron-withdrawing substituents cause shielding, while electron-donating ones behave oppositely, the inductive effects clearly predominating over the resonance effects. In contrast, the aniline substituents Y exert normal effects: electron-withdrawing substituents cause deshielding, while electron-donating ones cause shielding of the C=N carbon, the strengths of the inductive and resonance effects being closely similar. Additionally, the presence of a specific cross-interaction between X and Y could be verified. The electronic effects of the neighboring aromatic ring substituents systematically modify the sensitivity of the C=N group to the electronic effects of the benzylidene or aniline ring substituents. Electron-withdrawing substituents on the aniline ring decrease the sensitivity of δc(C=N) to the substitution on the benzylidine ring, while electron-donating substituents have the opposite effect. In contrast, electron-withdrawing substituents on the benzylidene ring increase the sensitivity of δc(C=N) to the substituent on the aniline ring, while electron-donating substituents act in the opposite way. These results can be rationalized in terms of the substituent-sensitive balance of the electron delocalization (mesomeric effects). The present NMR characteristics are discussed as regards the computational literature data. Valuable information has been obtained on the effects of the substituents on the molecular core of the mesogenic model compounds.
- Neuvonen, Helmi,Neuvonen, Kari,Fueloep, Ferenc
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p. 3141 - 3148
(2007/10/03)
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- Silica gel supported sodium hydrogen sulfate as an efficient and reusable heterogeneous catalyst for the synthesis of imines in solvent-free conditions under microwave irradiation
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This synthesis of imines has been carried out efficiently by the condensation of carbonyl compounds with amines in the presence of silica gel supported sodium hydrogen sulfate (NaHSO4.SiO2) as a heterogeneous catalyst under microwave irradiation in solvent-free conditions. NaHSO4.SiO2 can be recovered and re-used up to ten times by simple washing with diethyl ether after each use and activated in an oven at 120°C for 1 h, thus rendering the process more economical.
- Gopalakrishnan, Mannathusamy,Sureshkumar, Purushothaman,Kanagarajan, Vijayakumar,Thanusu, Jeyaraman,Govindaraju, Ramalingam
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p. 299 - 303
(2007/10/03)
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- Magnesium perchlorate as an efficient catalyst for the synthesis of imines and phenylhydrazones
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Magnesium perchlorate has been found to be an efficient catalyst for the synthesis of imines and phenylhydrazones by the reaction of carbonyl compounds with amines and phenylhydrazine in high yields at room temperatures and in short times. The condensation of less electrophilic carbonyl compounds with poorly nucleophilic amines affords the imines in excellent yields.
- Chakraborti, Asit K.,Bhagat, Srikant,Rudrawar, Santosh
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p. 7641 - 7644
(2007/10/03)
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- SUBSTITUENT EFFECTS ON THE 31P, 13C, AND 1H NMR CHEMICAL SHIFTS OF SUBSTITUTED DIPHENYL 1-PHENYLAMINO-1-PHENYLMETHANEPHOSPHONATES AND THEIR ANIONS
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For a series of thirty-five novel diphenyl 1-phenylamino-1-phenylmethanephosphonates, substituted in the meta and para positions on the anilino and/or aryl ring, 31P chemical shifts show a good linear correlation with Hammett ?n and Taft ?0 parameters, the 31P nucleus being better shielded in the case of electron withdrawing substituents.The same pattern is observed for the phosphonate anions, except when para phenyl substituents can interact with the phosphorus atom by direct resonance.This inverse relationship is due to a field effect of the substituent dipole which polarizes ?-electron clouds in the molecule.A corresponding shift in ?-electron density is likewise observed for 13C resonances of the two diastereotopic phenoxy groups, the phenylamino and phenyl moieties.Vicinal CH-NH coupling is shown to be dependent on the rate of NH proton exchange as influenced by resonance, temperature and solvent effects.
- Smith, Scott J.,Zimmer, Hans,Fluck, Ekkehard,Fischer, Peter
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p. 105 - 120
(2007/10/02)
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- Synthesis of β-Lactams from Imines and 1-Lithio-oxy-2-phenylacetylene
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The ynolate 1-lithio-oxy-2-phenylacetylene, prepared from 3,4-diphenylisoxazole and n-butyl-lithium in tetrahydrofuran at -78 deg C, condensed with the electron deficient imines (R1N=CH2R2) to give the β-lactams (R1 = C6H4NO2-
- Barrett, Anthony G. M.,Quayle, Peter
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p. 2193 - 2196
(2007/10/02)
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- Mesomorphic Properties of Some Nitro Substituted Azomethines
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The homologous series of 4'-n-alkoxybenzylidene-4-nitroanilines (I) and 4"-n-alkoxybenzylidene-4'-amino-4-nitrobiphenyls (II) have been synthesized and their mesomorphic properties investigated.Generally, the alkoxybenzylidenenitroanilines show only monot
- Reiffenrath, V.,Schneider, F.,Sharma, N. K.
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p. 869 - 872
(2007/10/02)
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