20192-50-1Relevant academic research and scientific papers
Triarylmethyl Cation-Catalyzed Three-Component Coupling for the Synthesis of Unsymmetrical Bisindolylmethanes
Bardelski, Kevin,Brindle, Cheyenne S.,Chen, Zhenghua,Guarino-Hotz, Melissa,Jones, Vanessa A.,Lucas, Kelly,Patterson, William J.
supporting information, p. 6737 - 6742 (2021/12/31)
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.
Observation of the complex spectra for the supramolecular system involving silver nanoparticles-biaryl Schiff bases containing the nitro group
Cao, Chao-Tun,Cheng, Shi-Mao,Cao, Chenzhong
, (2020/02/11)
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.
Dual Heterogeneous Catalyst Pd-Au@Mn(II)-MOF for One-Pot Tandem Synthesis of Imines from Alcohols and Amines
Chen, Gong-Jun,Ma, Hui-Chao,Xin, Wen-Ling,Li, Xiao-Bo,Jin, Fa-Zheng,Wang, Jing-Si,Liu, Ming-Yang,Dong, Yu-Bin
, p. 654 - 660 (2017/01/13)
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.
Silver-catalyzed one-step synthesis of multiply substituted quinolines
Xu, Xuefeng,Liu, Wenmin,Wang, Zhiqiang,Feng, Yuquan,Yan, Yanlei,Zhang, Xu
supporting information, p. 226 - 229 (2015/12/31)
A silver-catalyzed formation of C-C bond for the construction of a series of polysubstituted quinolines from arylamines, aldehydes, and ketones or arylamines and 1,3-diketones has been developed. The transformation is effective for a broad range of substrates, thus enabling the expansion of constituent architectures on the heterocyclic framework. This use of a single catalytic system to mediate chemical transformations in a synthetic operation is important for the development of new atom-economic strategies and this strategy is efficient in building complex structures from simple starting materials in an environmentally benign fashion.
Grinding synthesis of schiff bases combined with infrared irradiation
Tong, Jian-Ying,Sun, Na-Bo,Wu, Hong-Ke
, p. 5399 - 5401 (2013/07/26)
Solid-phase synthesis combined with infrared irradiation promoted the formation of a series of Schiff bases in the condensation reaction between substituted benzaldehydes and anilines, in the solvent free. Benzaldehydes and anilines, containing either electron withdrawing or electron-releasing groups, were evaluated their substituent effect on the formation of the Schiff bases. Moreover, this new procedure is environmentally benign because no solvent was employed in the transformations.
Silver-mediated C-H activation: Oxidative coupling/cyclization of N -arylimines and alkynes for the synthesis of quinolines
Zhang, Xu,Liu, Baoqing,Shu, Xin,Gao, Yang,Lv, Haipeng,Zhu, Jin
experimental part, p. 501 - 510 (2012/03/08)
A silver-mediated tandem protocol for the synthesis of quinolines involving the oxidative coupling/cyclization of N-arylimines and alkynes has been developed. We demonstrated that scenario-dependent metalation could occur either at the ortho C-H bond of an N-arylimine through protonation-driven enhancement of acidity or at the terminal C-H bond of an alkyne by virtue of the carbophilic π-acidity of silver. The diverse set of mechanistic manifolds implemented with a single type of experimental protocol points toward the importance of stringent reactivity analysis of each individual potentially reactive molecular site. Importantly, the direct arene C-H bond activation provides a unique and distinct mechanistic handle for the expansion of reactivity paradigms for silver. As expected, the protocol allows for the incorporation of both internal and terminal alkynes into the products, and in addition, both electron-withdrawing and -donating groups are tolerated on N-arylimines, thus enabling the vast expansion of substituent architectures on quinoline framework. Further, an intriguing phenomenon of structural isomerization and chemical bond cleavage has been observed for aliphatic internal alkynes.
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
Neuvonen, Helmi,Neuvonen, Kari,Fueloep, Ferenc
, p. 3141 - 3148 (2007/10/03)
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.
