55532-21-3Relevant academic research and scientific papers
Efficient Mizoroki–Heck coupling reactions using phosphine-modified Pd(II)–picolinate complex
Sharma, Sonam,Sarkar, Bibhas R.
supporting information, p. 906 - 914 (2018/03/21)
Efficient Mizoroki–Heck couplings were obtained using a very easily synthesizable palladium(II) complex of hemilabile N–O ligand (picolinate), with high turnover frequencies up to >10,000 h?1, in just 15 min, with high selectivity of >99% to the desired products. Wide applicability of the simple-looking palladium complex catalyst was established with differently functionalized substrates. Catalyst screening studies revealed intricate details of dependence of catalyst performance on different reaction parameters and conditions and arriving at the optimized facile methodology.
Activation of anti-oxidant Nrf2 signaling by substituted trans stilbenes
Deck, Lorraine M.,Whalen, Lisa J.,Hunsaker, Lucy A.,Royer, Robert E.,Vander Jagt, David L.
, p. 1423 - 1430 (2017/02/18)
Nrf2, which is a member of the cap'n’ collar family of transcription factors, is a major regulator of phase II detoxification and anti-oxidant genes as well as anti-inflammatory and neuroprotective genes. The importance of inflammation and oxidative stress in many chronic diseases supports the concept that activation of anti-oxidant Nrf2 signaling may have therapeutic potential. A number of Nrf2 activators have entered into clinical trials. Nrf2 exists in the cytosol in complex with its binding partner Keap1, which is a thiol-rich redox-sensing protein. In response to oxidative and electrophilic stress, select cysteine residues of Keap1 are modified, which locks Keap1 in the Nrf2-Keap1 complex and allows newly synthesized Nrf2 to enter the nucleus. Numerous Nrf2-activating chemicals, including a number of natural products, are electrophiles that modify Keap1, often by Michael addition, leading to activation of Nrf2. One concern with the design of Nrf2 activators that are electrophilic covalent modifiers of Keap1 is the issue of selectivity. In the present study, substituted trans stilbenes were identified as activators of Nrf2. These activators of Nrf2 are not highly electrophilic and therefore are unlikely to activate Nrf2 through covalent modification of Keap1. Dose-response studies demonstrated that a range of substituents on either ring of the trans stilbenes, especially fluorine and methoxy substituents, influenced not only the sensitivity to activation, reflected in EC50values, but also the extent of activation, which suggests that multiple mechanisms are involved in the activation of Nrf2. The stilbene backbone appears to be a privileged scaffold for development of a new class of Nrf2 activators.
Immobilized Pd on (S)-methyl histidinate-modified multi-walled carbon nanotubes: A powerful and recyclable catalyst for Mizoroki-Heck and Suzuki-Miyaura C-C cross-coupling reactions in green solvents and under mild conditions
Hajipour, Abdol R.,Khorsandi, Zahra
, p. 256 - 261 (2016/05/02)
A stable and powerful heterogeneous palladium catalyst was synthesized using immobilized palladium on (S)-methyl histidinate bonded onto the surface of multi-walled carbon nanotubes. The catalyst was characterized using a combination of Fourier transform infrared and X-ray photoelectron spectroscopies, transmission electron microscopy, X-ray powder diffraction and inductively coupled plasma, thermogravimetric and elemental analyses. This new air- and moisture-stable phosphine-free palladium catalyst was found to be highly active and reusable in Mizoroki-Heck and Suzuki-Miyaura cross-coupling reactions in poly(ethylene glycol) and aqueous ethanol as green solvents using an extremely small amount of palladium under mild conditions.
Oxidative Mizoroki-Heck-type reaction of arylsulfonyl hydrazides for a highly regio- and stereoselective synthesis of polysubstituted alkenes
Yang, Fu-Lai,Ma, Xian-Tao,Tian, Shi-Kai
supporting information; experimental part, p. 1582 - 1585 (2012/03/11)
A useful source: Arylsulfonyl hydrazides have been identified as synthetically useful aryl sources for the Pd(OAc)2 catalyzed oxidative Mizoroki-Heck-type reaction under molecular oxygen to provide a convenient access to polysubstituted alkenes in a highly regio- and stereoselective manner (see scheme). The reaction well tolerates various functional groups such as alkoxy, halo, alcohol, carboxylic acid, ester, amide, sulfonamide, and sulfone. Copyright
Asymmetrically substituted distyrylbenzenes and their polar crystal structures
Collas, Alain,Borger, Roeland De,Amanova, Tatyana,Vande Velde, Christophe M. L.,Baeke, Jan K.,Dommisse, Roger,Alsenoy, Christian Van,Blockhuys, Frank
scheme or table, p. 649 - 662 (2011/06/20)
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.
Non-competitive and selective dipeptidyl peptidase IV inhibitors with phenethylphenylphthalimide skeleton derived from thalidomide-related α-glucosidase inhibitors and liver X receptor antagonists
Motoshima, Kazunori,Sugita, Kazuyuki,Hashimoto, Yuichi,Ishikawa, Minoru
, p. 3041 - 3045 (2011/06/24)
Novel dipeptidyl peptidase IV (DPP-IV) inhibitors with a phenethylphenylphthalimide skeleton were prepared based on α-glucosidase inhibitors and liver X receptor (LXR) antagonists derived from thalidomide. Representative compounds showed non-competitive i
Heck reactions using segmented flow conditions
Ahmed-Omer, Batoul,Barrow, David A.,Wirth, Thomas
scheme or table, p. 3352 - 3355 (2009/08/17)
Various Heck couplings have been carried out using segmented flow conditions to accelerate the reactions. Aryl iodides and aryl bromides as well as anilines in diazonium-type Heck reactions have been used successfully.
Catalytic activity of Pd(II) and Pd(II)/DAB-R systems for the Heck arylation of olefins
Grasa, Gabriela A.,Singh, Rohit,Stevens, Edwin D.,Nolan, Steven P.
, p. 269 - 279 (2007/10/03)
Palladium-catalyzed reactions of aryl bromides with various olefins involving Pd(II)/diazabutadiene (DAB-R) systems have been investigated. The scope of a coupling process using Pd(II) sources and an α-diimine as ligand in the presence of Cs2CO3 as base was tested using various substrates. The Pd(OAc)2/ DAB-Cy (1, DAB-Cy=1,4-dicyclohexyl-diazabutadiene) system presents the highest activity with respect to electron-neutral and electron-deficient aryl bromides in coupling with electron rich olefins. The synthesis and X-ray characterization of a Pd(II)-diazabutadiene ligand is reported. Extensive optimization experiments showed that another Pd(II) source, Pd(acac)2 (acac=acetylacetonate), proved to activate aryl bromides at high temperatures, low catalyst loadings when the appropriate concentration of nBu4NBr additive was employed. The effect of the DAB-Cy ligand is important at very low catalyst loadings and high temperatures. Pd(acac)2 and Pd(acac)2 /DAB-Cy precatalysts were very effective for the arylation of various olefins with aryl bromides with respect to reaction rate, catalyst loadings, and functional group tolerance.
KINETICS AND LINEAR FREE ENERGY RELATIONSHIP OF WITTIG REACTION BETWEEN SUBSTITUTED BENZALDEHYDES AND SUBSTITUTED BENZYLIDENETRIPHENYLPHOSPHORANE
Donxia, Li,Dexian, Wu,Yaozhong, Li,Huaming, Zhao
, p. 4161 - 4168 (2007/10/02)
Kinetics and linear free energy relationship (LFER) of Wittig reaction of ylides of intermediary stability have been investigated.Evidences are presented which indicate that under such cases the reaction follows a second order rate law, first order in phosphorane and aldehyde respectively, and furthermore that electron withdrawing substituents on both benzaldehyde and benzylidenetriphenylphosphorane impose rate enhancement effect upon the reaction.The mechanism of the reaction is discussed on the basis of the experimental findings
