583-17-5Relevant articles and documents
Palladium nanoparticles immobilized on amphiphilic and hyperbranched polymer-functionalized magnetic nanoparticles: An efficient semi-heterogeneous catalyst for Heck reaction
Tabatabaei Rezaei, Seyed Jamal,Shamseddin, Azin,Ramazani, Ali,Mashhadi Malekzadeh, Asemeh,Azimzadeh Asiabi, Pegah
, (2017/09/01)
To address the obstacles facing the use of palladium-based homogeneous and heterogeneous catalysts in C─C cross-coupling reactions, a novel semi-heterogeneous support was developed based on hyperbranched poly(ethylene glycol)-block-poly(citric acid)-functionalized Fe3O4 magnetic nanoparticles (Fe3O4@PCA-b-PEG). Because of the surface modification of the Fe3O4 nanoparticles with amphiphilic and hyperbranched polymers (PCA-b-PEG), these hybrid materials are not only soluble in a wide range of solvents (e.g. water, ethanol and dimethylformamide) but also are able to trap Pd2+ ions via complex formation of free carboxyl groups of the PCA dendrimer with metal ions. The reduction of trapped palladium ions in the dendritic shell of Fe3O4@PCA-b-PEG leads to immobilized palladium nanoparticles. The morphology and structural features of the catalyst were characterized using various microscopic and spectroscopic techniques. The catalyst was effectively used in the palladium-catalysed Mizoroki–Heck coupling reaction in water as a green solvent. In addition, the catalyst can be easily recovered from the reaction mixture by applying an external magnetic field and reused for more than ten consecutive cycles without much loss in activity, exhibiting an example of a sustainable and green methodology.
Curcumin recognizes a unique binding site of tubulin
Chakraborti, Soumyananda,Das, Lalita,Kapoor, Neha,Das, Amlan,Dwivedi, Vishnu,Poddar, Asim,Chakraborti, Gopal,Janik, Mark,Basu, Gautam,Panda, Dulal,Chakrabarti, Pinak,Surolia, Avadhesha,Bhattacharyya, Bhabatarak
experimental part, p. 6183 - 6196 (2011/11/06)
Although curcumin is known for its anticarcinogenic properties, the exact mechanism of its action or the identity of the target receptor is not completely understood. Studies on a series of curcumin analogues, synthesized to investigate their tubulin binding affinities and tubulin self-assembly inhibition, showed that: (i) curcumin acts as a bifunctional ligand, (ii) analogues with substitution at the diketone and acetylation of the terminal phenolic groups of curcumin are less effective, (iii) a benzylidiene derivative, compound 7, is more effective than curcumin in inhibiting tubulin self-assembly. Cell-based studies also showed compound 7 to be more effective than curcumin. Using fluorescence spectroscopy we show that curcumin binds tubulin 32 ? away from the colchicine-binding site. Docking studies also suggests that the curcumin-binding site to be close to the vinblastine-binding site. Structure-activity studies suggest that the tridented nature of compound 7 is responsible for its higher affinity for tubulin compared to curcumin.
7,8-Disubstituted- but not 6,7-disubstituted coumarins selectively inhibit the transmembrane, tumor-associated carbonic anhydrase isoforms IX and XII over the cytosolic ones i and II in the low nanomolar/subnanomolar range
Maresca, Alfonso,Scozzafava, Andrea,Supuran, Claudiu T.
scheme or table, p. 7255 - 7258 (2011/01/12)
Two series of disubstituted coumarins incorporating ether and acetyl/propionyl moieties in positions 6,7- and 7,8- of the heterocyclic ring were synthesized investigated for the inhibition of the zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1). All these
