3650-77-9Relevant academic research and scientific papers
In situ synthesis of carbon nanotube-encapsulated cobalt nanoparticles by a novel and simple chemical treatment process: Efficient and green catalysts for the Heck reaction
Hajipour, Abdol R.,Khorsandi, Zahra,Farrokhpour, Hossein
supporting information, p. 8215 - 8219 (2019/06/07)
In this study, we present a novel, fast and easy method for supporting metal nanoparticles onto the internal surface of multi-walled CNTs; these CNT-encapsulated nanoparticles as heterogeneous, efficient, inexpensive and green catalysts promote the Heck cross-coupling of a large library of functional substrates under mild and sustainable conditions. Remarkably, the introduced catalytic system could be reused for at least nine successive runs without a discernible decrease in its catalytic activity.
Magnetic iron oxide nanoparticles–N-heterocyclic carbene–palladium(II): a new, efficient and robust recyclable catalyst for Mizoroki–Heck and Suzuki–Miyaura coupling reactions
Hajipour, Abdol R.,Tadayoni, Nayereh S.,Khorsandi, Zahra
, p. 590 - 595 (2016/07/16)
A new and efficient nanoparticle–N-heterocyclic carbene–palladium complex was synthesized and characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, field emission scanning electron microscopy, energy-dispersive X-ray analysis, X-ray diffraction, transmission electron microscopy, elemental analysis, inductively coupled plasma analysis and vibrating sample magnetometry. This catalytic system was found to be a highly active catalyst in the Mizoroki–Heck and Suzuki–Miyaura cross-coupling reactions. These reactions were best performed in dimethylformamide and water, respectively, in the presence of only 0.054 mol% of palladium under mild conditions. Moreover, the catalyst could be recovered easily and reused at least ten times without any considerable loss of its catalytic activity. Copyright
Phototriggerable peptidomimetics for the inhibition of Mycobacterium tuberculosis ribonucleotide reductase by targeting protein-protein binding
Karlsson, Christoffer,Blom, Magnus,Johansson, Miranda,Jansson, Anna M.,Scifo, Enzo,Karln, Anders,Govender, Thavendran,Gogoll, Adolf
supporting information, p. 2612 - 2621 (2015/05/27)
Incorporation of an artificial amino acid 2 with a stilbene chromophore into peptidomimetics with three to nine amino acids yields phototriggerable candidates for inhibition of the binding between the R1 and R2 subunits of the M. tuberculosis ribonucleotide reductase (RNR). Interstrand hydrogen bond probability was used as a guideline for predicting conformational preferences of the photoisomers. Binding of these inhibitors has been rationalized by docking studies with the R1 unit. Significant differences in binding of the photoisomers were observed. For the shorter peptidomimetics, stronger binding of the Z isomer might indicate hydrophobic interactions between the stilbene chromophore and the binding site. This journal is
Cross-Linked Thiazolidine Network as Support for Palladium: A New Catalyst for Suzuki and Heck Reactions
Bivona, Lucia Anna,Giacalone, Francesco,Vaccaro, Luigi,Aprile, Carmela,Gruttadauria, Michelangelo
, p. 2526 - 2533 (2015/08/24)
A thiazolidine-based material was used for the first time as support for palladium. The support was prepared by starting from a highly cross-linked thiazolium-based material, obtained by radical oligomerization of a bisvinylthiazolium dibromide salt in the presence of 3-mercaptopropyl-modified silica SBA-15. Palladium was immobilized by treatment with tetrachloropalladate salt. Reduction with sodium borohydride afforded a thiazolidine-based material that acted as ligands for the Pd species. The thiazolidine-based palladium catalyst was fully characterized and, working in only 0.1 mol% amount, displayed good activity in the Suzuki-Miyaura and in the Heck reactions. Several biphenyl and alkene compounds could be prepared in high yields. The catalytic material proved to be fully recoverable and it was representatively used for three times in the Suzuki-Miyaura reaction without showing any decrease in its activity.
Evaluation of SILP-Pd catalysts for Heck reactions in a microfluidics-based high throughput flow reactor
Urbán, Béla,Srankó, Dávid,Sáfrán, Gy?rgy,ürge, László,Darvas, Ferenc,Bakos, József,Skoda-F?ldes, Rita
, p. 364 - 372 (2014/12/10)
Heck reaction of aryl iodides and methyl acrylate was carried out in an X-Cube reactor in the presence of supported catalysts. Palladium was immobilised by different methods on silica with covalently grafted ionic liquid moieties. Activity and selectivity of the SILP-Pd (supported ionic liquid phase) catalysts were found to depend greatly on the conditions (such as solvent and additives) of immobilisation. By the proper choice of the methodology used during heterogenisation, a selective catalyst, showing stable performance for hours on stream, was obtained.
Phosphine-catalyzed domino reactions: A route to functionalized bicyclic skeletons
Li, Erqing,Huang, You
supporting information, p. 3520 - 3527 (2014/04/03)
A novel strategy that involves phosphine-catalyzed sequential [2+3] and [3+2] annulation reactions was developed. In this domino reaction, γ-substituted allenoates were used as novel C4 synthons, and the bicyclic cyclopenta[b]dihydrofuran derivatives were produced in good to excellent diastereoselectivities and yields under mild conditions. Furthermore, preliminary studies on an asymmetric variant of this reaction proceeded with moderate enantioselectivity.
Catalytic asymmetric cross-dehydrogenative coupling: Activation of C-H bonds by a cooperative bimetallic catalyst system
Cao, Weidi,Liu, Xiaohua,Peng, Ruixue,He, Peng,Lin, Lili,Feng, Xiaoming
supporting information, p. 3470 - 3472 (2013/05/23)
A cooperative bimetallic catalyst system was applied in the catalytic asymmetric cross-dehydrogenative coupling of β-ketoesters and xanthene. Various optically active xanthene derivatives bearing a quaternary stereogenic carbon center were obtained in moderate to good yields (up to 90%) with excellent enantioselectivities (up to 99% ee). Meanwhile, a transition-state model was proposed to explain the origin of the asymmetric induction.
Photochemical regulation of an artificial hydrolase by a backbone incorporated tertiary structure switch
Lindgren, N. Johan V.,Varedian, Miranda,Gogoll, Adolf
supporting information; experimental part, p. 501 - 505 (2009/07/10)
A stilbene chromophore has been incorporated into the turn region of a 42 amino acid peptide, linking two helical peptide sections. Spatial proximity between these sections, as well as aggregation into dimers, is required to facilitate the catalytic function of this artificial hydrolase. Photomodulation of the hydrolase activity results in an increase of the activity of 42% upon switching from the trans to the cis isomer of the chromophore. This is rationalized by a change in the aggregation state of the peptidomimetic, which is supported by diffusion coefficients obtained from PFG-NMR experiments. The results show that incorporation of a small, relatively flexible chromophore into a large peptide is capable of inducing a considerable change in tertiary structure and thus, functionality.
Chemistry and folding of photomodulable peptides - Stilbene and thioaurone-type candidates for conformational switches
Erdelyi, Mate,Varedian, Miranda,Skoeld, Christian,Niklasson, Ida B.,Nurbo, Johanna,Persson, Asa,Bergquist, Jonas,Gogoll, Adolf
scheme or table, p. 4356 - 4373 (2009/02/07)
Optimized synthetic strategies for the preparation of photoswitchable molecular scaffolds based on stilbene or on thioaurone chromophores and their conformationally directing properties, as studied by computations and by NMR spectroscopy, are addressed. For the stilbene peptidomimetics 1, 2 and 3, the length of connecting linkers between the chromophore and the peptide strands was varied, resulting in photochromic dipeptidomimetics with various flexibility. Building blocks of higher rigidity, based on para-substituted thioaurone (4 and 6) and meta-substituted thioaurone chromophores (5 and 7) are shown to have a stronger conformationally directing effect. Design, synthesis, theoretical and experimental conformational analyses are presented.
Protonation of Substituted Methyl Cinnamates
Sarkice, Aramice Y.,Zalewski, Romuald I.
, p. 515 - 518 (2007/10/02)
The protonation of methyl cinnamate and its eight meta and para derivatives has been studied by ultraviolet spectrophotometry in perchloric acid. pKBH+ value of methyl cinnamate calculated by characteristic vector analysis-titration curve analysis is -4.41.Methyl cinnamate is a weaker base than cinnamic acid.All esters studied follow amide acidity function HA in their protonation.The effect of substituents on pKBH+ has been expressed in terms of Hammett equation with the reaction constant ρ = -0.483.
