- Palladium(ii) ligated with a selenated (Se, CNHC, N-)-type pincer ligand: An efficient catalyst for Mizoroki-Heck and Suzuki-Miyaura coupling in water
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A new 1-[N-benzylacetamido]-3-[1-(2-phenylselenylethyl)]benzimidazolium chloride (L), the precursor of a novel (Se, CNHC, N-)-type pincer ligand (L) was synthesised in high yield through a sequence of consecutive reactions of 1H-benzimidazole with ethylene dichloride, sodium selenophenolate, and N-benzyl-2-chloroacetamide. The palladium-promoted reaction of L with PdCl2 resulted in a moisture- and air-insensitive complex [Pd(L-H2Cl)Cl] (1), which demonstrated outstanding catalytic potential for Mizoroki-Heck coupling of aromatic bromides and chlorides (with yields up to 94% and 70%, respectively) at very low catalyst loading (0.2 mol%) and under mild reaction conditions in water. The complex (1) was also investigated for Suzuki-Miyaura coupling and found to be selectively efficient (yields up to 94%) for Suzuki-Miyaura coupling of aromatic bromides at 0.01 mol% of 1 in water. All coupling reactions were carried out in the green and economical solvent, water, which is highly desirable for bulk synthesis of complex molecules in industry. During the catalytic process, complex 1 converted into PdSe nanoparticles (NPs, size range 5-6 nm) in situ. The morphology and composition of these NPs were analysed through high-resolution transmission electron microscopy and transmission electron microscopy-energy dispersive X-ray spectroscopy, respectively. The core-level, X-ray photoelectron spectroscopy analysis confirmed the presence of stable Pd0 and Pd2+ oxidation states in these PdSe NPs. Based on further experimental investigations, these nanoparticles were found to work as a stock of true catalytic species. The hot filtration test, as well as the two-phase test, confirmed the largely homogeneous nature of the catalytic process, which probably proceeds by leaching of solution-phase Pd species from these NPs.
- Sharma, Kamal Nayan,Satrawala, Naveen,Srivastava, Avinash Kumar,Ali, Munsaf,Joshi, Raj Kumar
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- Pd/Cu-catalyzed facile approach to stilbenes: A novel diversity of TosMIC as an aryl source
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Pd/Cu-catalyzed Heck type cross-coupling reaction of p-toluenesulfonylmethyl isocyanide (TosMIC) with various styrenes to access stilbenes in DMSO solvent under mild conditions is developed. This efficient and simple approach employs TosMIC as an aryl sou
- Kadari, Lingaswamy,Palakodety, Radha Krishna
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Read Online
- Efficient deep blue emission by 4-styrylbenzonitrile derivatives in solid state: Synthesis, aggregation induced emission characteristics and crystal structures
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Organic fluorescent molecules with π-conjugated system have shown great importance in numerous applications including bioimaging and optoelectronics. Planar aggregation-induced emissive (AIE) organic compounds with efficient solid-state luminescence are rarely developed and urgently needed in various applications. In this work, highly planar 4-styrylbenzonitrile derivatives have been synthesized. Most of these compounds show strong AIE properties with hundred-fold fluorescent enhancement. Moreover, these molecules are deep blue emissive in solid state, exhibiting good to excellent fluorescence quantum efficiency. The single crystal analysis shows that adjacent molecules could form special J-type aggregation. The intramolecular rotations are efficiently restricted by various noncovalent interactions. These molecular arrangements could be essential for the observed strong emission in aggregated and solid state. This work has paved a new path to efficient AIE-active organic emitters with highly planar conformations from 4-styrylbenzonitrile structure.
- Fang, Ying,Meng, Yuanyuan,Yuan, Chunming,Du, Chunhui,Wang, Kun-Peng,Chen, Shaojin,Hu, Zhi-Qiang
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- N-Heterocyclic carbene palladium (II)-pyridine (NHC-Pd (II)-Py) complex catalyzed heck reactions
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A mild, efficient, and practical catalytic system for the synthesis of highly privileged stilbene pharmacophores is reported. This system uses N-heterocyclic carbene palladium (II) Pyridine (NHC-Pd (II)-Py) complex to catalyze the formation of carbon-carbon bonds between olefin derivatives and various bromide. This simple, gentle and user-friendly method can offer a variety of stilbene products in excellent yields under solvent-free condition. And its scale-up reaction has excellent yield and this system can be applied to industrial fields. The utility of this method is highlighted by its universality and modular synthesis of a series of bioactive molecules or important medical intermediates.
- Li, Dan,Tian, Qingqiang,Wang, Xuetong,Wang, Qiang,Wang, Yin,Liao, Siwei,Xu, Ping,Huang, Xin,Yuan, Jianyong
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supporting information
p. 2041 - 2052
(2021/05/25)
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- Direct Wittig Olefination of Alcohols
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A base-promoted transition metal-free approach to substituted alkenes using alcohols under aerobic conditions using air as the inexpensive and clean oxidant is described. Aldehydes are relatively difficult to handle compared to corresponding alcohols due to their volatility and penchant to polymerize and autoxidize. Wittig ylides are easily oxidized to aldehydes and consequently form homo-olefination products. By the strategy of simultaneously in situ generation of ylides and aldehydes, for the first time, alcohols are directly transferred to olefins with no need of prepreparation of either aldehydes or ylides. Thus, the di/monocontrollable olefination of diols is accomplished. This synthetically practical method has been applied in the gram-scale synthesis of pharmaceuticals, such as DMU-212 and resveratrol from alcohols.
- Li, Qiang-Qiang,Shah, Zaher,Qu, Jian-Ping,Kang, Yan-Biao
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p. 296 - 302
(2018/02/19)
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- Development and evaluation of 4-(pyrrolidin-3-yl)benzonitrile derivatives as inhibitors of lysine specific demethylase 1
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As part of our ongoing efforts to develop reversible inhibitors of LSD1, we identified a series of 4-(pyrrolidin-3-yl)benzonitrile derivatives that act as successful scaffold-hops of the literature inhibitor GSK-690. The most active compound, 21g, demonstrated a Kd value of 22 nM and a biochemical IC50 of 57 nM. In addition, this compound displayed improved selectivity over the hERG ion channel compared to GSK-690, and no activity against the related enzymes MAO-A and B. In human THP-1 acute myeloid leukaemia cells, 21g was found to increase the expression of the surrogate cellular biomarker CD86. This work further demonstrates the versatility of scaffold-hopping as a method to develop structurally diverse, potent inhibitors of LSD1.
- Mould, Daniel P.,Bremberg, Ulf,Jordan, Allan M.,Geitmann, Matthis,McGonagle, Alison E.,Somervaille, Tim C.P.,Spencer, Gary J.,Ogilvie, Donald J.
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p. 4755 - 4759
(2017/09/29)
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- Direct trans-Selective Ruthenium-Catalyzed Reduction of Alkynes in Two-Chamber Reactors and Continuous Flow
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An efficient trans-selective hydrogenation of alkynes under low hydrogen pressure and low reaction temperatures is reported, applying a commercially available ruthenium hydride complex. The developed reaction conditions, which tolerate a variety of functional groups, are carried out in a two-chamber setup with ex situ generated hydrogen. The reaction setup is highly suitable for deuterium labeling. The trans-selective hydrogenation was extrapolated to a transfer hydrogenation protocol, employing a packed bed immobilized ruthenium hydride catalyst in continuous flow with a retention time of only 10 min.
- Neumann, Karoline T.,Klimczyk, Sebastian,Burhardt, Mia N.,Bang-Andersen, Benny,Skrydstrup, Troels,Lindhardt, Anders T.
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p. 4710 - 4714
(2016/07/12)
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- Effects of substituent and solvent on the UV absorption energy of 4,4′-disubstituted stilbenes
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Twenty five samples of 4,4′-disubstituted stilbene derivatives were synthesized, and their UV absorption max wavelengths were determined in over 10 kinds of solvents including cyclohexane, ether, chloroform, acetonitrile and ethanol, in which 242 experimental data were recorded. The effects of substituents and solvents on the energy of their UV absorption max wavelengths were discussed. The research results showed: the energy of UV absorption max wavelengths of 4,4′-disubstituted stilbenes was mainly affected by their intramolecular structure (substituent effect) in a given solvent, that is, the energy is dominated by both of excited-state substituent parameter σ CC ex and polar substituent constant σ p. While their energy was dominated by the substituent effect and solvent effect in different kinds of solvents. An equation quantifying the energy of UV absorption max wavelengths of 4,4′-disubstituted stilbenes was developed. In addition, it is found that the n-octanol/water partition coefficient (logP) is more effective than the solvatochromic dye (E T(30)) in scaling the solvent effect. The equation employed the parameter logP has a better correlation and more specific physical meaning. Further, the energies of UV absorption max wavelengths of some reported compounds were predicted by the obtained equation, which are in agreement with their experimental values.
- Cao, Chenzhong,Chen, Guanfan,Wu, Yaxin
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scheme or table
p. 1735 - 1744
(2012/05/05)
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- Asymmetrically substituted distyrylbenzenes and their polar crystal structures
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The synthesis of twelve asymmetric donor-acceptor distyrylbenzene derivatives with either one nitrile group or one, two or three nitro groups as electron acceptors, and one, two or three methoxy groups as electron donors is reported. Peak potentials obtained from cyclic voltammetry were combined with experimental UV/Vis data and molecular dipole moments obtained from quantum chemical calculations, yielding insight into the influence of the positions of the substituents on the electronic structure and charge distribution of this as yet unexplored class of organic semiconductors. The supramolecular structures of five of these compounds have been studied using single-crystal X-ray diffraction to monitor the influence of the positions of donor and acceptor groups on the organisation of the molecules in the solid state, and three crystal structures have been identified in which the molecular dipoles do not organize themselves in a centrosymmetric lattice. Analysis of the dipoles in the unit cell yields further insight into the possible non-linear optical properties of these three polar structures.
- Collas, Alain,Borger, Roeland De,Amanova, Tatyana,Vande Velde, Christophe M. L.,Baeke, Jan K.,Dommisse, Roger,Alsenoy, Christian Van,Blockhuys, Frank
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scheme or table
p. 649 - 662
(2011/06/20)
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- Rhodium-catalyzed alkenylation of nitriles via silicon-assisted C-CN bond cleavage
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Rhodium-catalyzed Mizoroki-Heck type reaction of nitriles via the cleavage of C-C bonds is described. Orthogonal and iterative functionalizations of arenes were also demonstrated by combining the present and conventional halide-based cross-coupling reacti
- Kita, Yusuke,Tobisu, Mamoru,Chatani, Naoto
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supporting information; experimental part
p. 1864 - 1867
(2010/10/02)
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- Mesomorphic donor-acceptor-substituted 1,4-distyrylbenzenes
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The (E,E)-distyrylbenzenes 1a, b with terminal donor-acceptor substitution were prepared by a sequence of four reaction steps including two Wittig-Horner reactions. The products form smectic mesophases, are photostable, and should permit an electric orien
- Lifka, Thorsten,Kalbitz, Helga,Meier, Herbert
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scheme or table
p. 1183 - 1186
(2010/03/01)
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- Design of ??-conjugated organic materials for one-dimensional energy transport in nanochannels
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Various end-substituted distyrylbenzenes have been synthesized to serve as guest molecules in inclusion compounds to promote efficient energy transport along one-dimensional channels. Their optical and photophysical properties have been characterized at b
- Sancho-Garciì?a, Juan Carlos,Breì?das, Jean-Luc,Beljonne, David,Cornil, Jeì?roì?me,Martiì?nez-Aì?lvarez, Roberto,Hanack, Michael,Poulsen, Lars,Gierschner, Johannes,Mack, Hans-Georg,Egelhaaf, Hans-Joachim,Oelkrug, Dieter
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p. 4872 - 4880
(2008/03/14)
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- Solvent-dependent fluorescence of donor-substituted (E)-1,2-bis(stilbenyl-1,3,4-oxadiazolyl)ethenes
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The Huisgen reaction of aryltetrazoles and fumaryl chloride leads to symmetrically aryl-substituted 1,2-bis(1,3,4-oxadiazolyl)ethenes. Molecules with extended conjugated systems are accessible using stilbenyltetrazoles or higher homologues. The substitution with solubility-permitting alkoxy side-chains results in molecules of C2h symmetry, consisting of a central electron-accepting segment and two terminal electron density-releasing units. The solvatochromism of the absorption spectra is negligible, while in the emission spectra a strong positive solvatochromism connected with a dramatic decrease of the quantum yield is observed, indicating intramolecular charge transfer. The influences of different alkoxy substitution patterns on the luminescence properties are discussed. Copyright
- Detert, Heiner,Sugiono, Erli,Kruse, Gabriele
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p. 638 - 641
(2007/10/03)
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- Amidine derivatives and cardiotonic compositions
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Amidine derivatives of the formula STR1 wherein R1 and R2, which may be the same or different, represent each a hydrogen atom or a lower alkyl group, or R1 and R2 together with an intermediary carbon atom and/or hetero atom may form a ring; X represents STR2 (wherein R8 represents a hydrogen atom, a lower alkyl group, or --CH2 COOR9, where R9 represents a hydrogen atom or a lower alkyl group; Z represents a single bond, --CH2 --, --CH2 CH2 --, or --CH=CH--); R3 represents a hydrogen or chlorine atom, methoxy group, nitro group, or amino group; Y represents --CH2 CH2 --, --CH=CH--, --CH2 O--, or --OCH2 --; R4 represents a hydrogen atom, methoxy group, benzoyl group, nitro group, or amino group; and R5, R6 and R7, which may be the same or different, represent each a hydrogen atom, lower alkyl group, cycloalkyl group, aralkyl group, substituted alkyl group, substituted aralkyl group, or amino group, or R5 and R7 may form a ring, or salts thereof have an excellent cardiotonic activity and can be used as cardiotonics.
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