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Stilbene Derivatives (stilbene + derivative)
Selected AbstractsSimple Ruthenium Precatalyst for the Synthesis of Stilbene Derivatives and Ring-Closing Metathesis in the Presence of Styrene InitiatorsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4-5 2007Cheikh Lo Abstract The ruthenium complex RuCl2(p -cymene)(IMes) was found to be an efficient precatalyst, with styrene as an initiating species, for the alkene metathesis of various styrenes into symmetrical and unsymmetrical stilbene derivatives and for the ring-closing metathesis reaction of a sterically hindered olefin leading to a tetrasubstituted cycloolefin. [source] Antioxidative and Prooxidative Action of Stilbene DerivativesBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 5 2000Toshiaki Miura The effects of stilbene derivatives, including resveratrol, diethylstilboestrol and stilbene, as antioxidants or prooxidants were examined. Resveratrol and diethylstilboestrol, but not stilbene, strongly inhibited NADPH- and adenosine 5,-diphosphate (ADP)-Fe3+ -dependent lipid peroxidation at the initial and propagation stages. In addition, phenolic stilbenes also inhibited ultraviolet light-induced lipid peroxidation. Resveratrol and diethylstilboestrol efficiently scavenged 2,2,-azobis-(2-amidinopropane)-dihydrochloride peroxyl radicals. However, 2,2,-diphenyl-p-picrylhydrazyl radicals were trapped only by resveratrol, but not by diethylstilboestrol. These results suggest that the inhibitory effect of phenolic stilbenes on lipid peroxidation was due to their scavenging ability of lipid peroxyl and/or carbon-cantered radicals. Resveratrol efficiently reduced ADP-Fe3+, but not EDTA-Fe3+. Stilbenes and diethylstilboestrol did not reduce either ADP-Fe3+ or EDTA-Fe3+. The strand breaks of DNA were stimulated during the interaction of resveratrol with ADP-Fe3+ in the presence of H2O2. These results suggest that phenolic stilbenes act as antioxidants of membrane lipids and that resveratrol has a prooxidative effect DNA damage during interaction with ADP-Fe3+ in the presence of H2O2. [source] Simple Ruthenium Precatalyst for the Synthesis of Stilbene Derivatives and Ring-Closing Metathesis in the Presence of Styrene Initiators.CHEMINFORM, Issue 28 2007Cheikh Lo Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] A cis -stilbene derivativeACTA CRYSTALLOGRAPHICA SECTION C, Issue 3 2003K. SethuSankar The title compound, 4,-methoxy-,,2,3,,4-tetranitrostilbene, C15H10N4O9, crystallizes in the centrosymmetric space group P21/c with one molecule in the asymmetric unit. The phenyl rings are inclined to one another and form a dihedral angle of 57.4,(1)°. The size of this angle is a result of intermolecular C,H,O interactions involving the phenyl H atoms. The torsion angle between the phenyl rings, ,7.5,(3)°, indicates a cis geometry between them. The methoxy group is almost coplanar with the phenyl ring, and the nitro groups are twisted with respect to the phenyl rings because of the short H,O contacts. The crystal packing is stabilized by C,H,O hydrogen bonds, and the intermolecular hydrogen bonds form a C(12) graph-set chain running along the [010] direction. [source] Simple Ruthenium Precatalyst for the Synthesis of Stilbene Derivatives and Ring-Closing Metathesis in the Presence of Styrene InitiatorsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4-5 2007Cheikh Lo Abstract The ruthenium complex RuCl2(p -cymene)(IMes) was found to be an efficient precatalyst, with styrene as an initiating species, for the alkene metathesis of various styrenes into symmetrical and unsymmetrical stilbene derivatives and for the ring-closing metathesis reaction of a sterically hindered olefin leading to a tetrasubstituted cycloolefin. [source] Effects of Naturally Occurring Stilbene Glucosides from Medicinal Plants and Wine, on Tumour Growth and Lung Metastasis in Lewis Lung Carcinoma-Bearing MiceJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 10 2000YOSHIYUKI KIMURA Stilbene glucosides are naturally occurring phytoalexins, found in a variety of medicinal plants. Among the stilbene derivatives, resveratrol 3- O -D-glucoside (piceid) is found in grapes and wine. We studied the effects of stilbene glucosides isolated from medicinal plants and grapes on tumour growth and lung metastasis in mice bearing highly metastastic Lewis lung carcinoma (LLC) tumours. We also studied the inhibitory effects of stilbene glucosides on differentiation of human umbilical vein endothelial cells (HUVECs) to form a capillary network. Tumour growth in the right hind paw and lung metastasis were inhibited by oral administration of the stilbene glucosides, piceid and 2,3,5,4,-tetrahydroxystilbene-2- O -D-glucoside for 33 consecutive days, in LLC-bearing mice. As the number of CD8+ and NK1.1+ T cells in the spleen was not affected, the inhibitory effects of these stilbene glucosides on tumour growth and lung metastasis could not be explained by natural killer or cytotoxic T lymphocyte activation. Piceid inhibited the DNA synthesis in LLC cells at a concentration of 1000 ,m, but not at lower concentrations (10,100 ,M). 2,3,5,4,-Tetra-hydroxystilbene-2- O -D-glucoside also inhibited DNA synthesis in LLC cells (IC50 81 ,M). In addition, both stilbene glucosides inhibited the formation of capillary-like tube networks (angiogenesis) of HUVECs at concentrations of 100 to 1000 ,M. We suggest that the antitumour and antimetastatic activity of the stilbene glucosides, piceid and 2,3,5,4,-tetrahydroxystilbene-2- O -D-glucoside, might be due to the inhibition of DNA synthesis in LLC cells and angiogenesis of HUVECs. [source] Antioxidative and Prooxidative Action of Stilbene DerivativesBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 5 2000Toshiaki Miura The effects of stilbene derivatives, including resveratrol, diethylstilboestrol and stilbene, as antioxidants or prooxidants were examined. Resveratrol and diethylstilboestrol, but not stilbene, strongly inhibited NADPH- and adenosine 5,-diphosphate (ADP)-Fe3+ -dependent lipid peroxidation at the initial and propagation stages. In addition, phenolic stilbenes also inhibited ultraviolet light-induced lipid peroxidation. Resveratrol and diethylstilboestrol efficiently scavenged 2,2,-azobis-(2-amidinopropane)-dihydrochloride peroxyl radicals. However, 2,2,-diphenyl-p-picrylhydrazyl radicals were trapped only by resveratrol, but not by diethylstilboestrol. These results suggest that the inhibitory effect of phenolic stilbenes on lipid peroxidation was due to their scavenging ability of lipid peroxyl and/or carbon-cantered radicals. Resveratrol efficiently reduced ADP-Fe3+, but not EDTA-Fe3+. Stilbenes and diethylstilboestrol did not reduce either ADP-Fe3+ or EDTA-Fe3+. The strand breaks of DNA were stimulated during the interaction of resveratrol with ADP-Fe3+ in the presence of H2O2. These results suggest that phenolic stilbenes act as antioxidants of membrane lipids and that resveratrol has a prooxidative effect DNA damage during interaction with ADP-Fe3+ in the presence of H2O2. [source] Ramberg-Bäcklund Rearrangement Approaches to the Synthesis of Natural BibenzylsCHINESE JOURNAL OF CHEMISTRY, Issue 5 2004Xiao-Long Wang Abstract The Ramberg-Bäcklund rearrangement has been successfully utilized to convert readily available ,- and ,'-hydrogen bearing substituted dibenzyl sulfones into corresponding stilbene derivatives, which is conveniently followed by hydrogenation in the presence of 10% Pd/C to afford the natural bibenzyls. [source] Theoretical Study on Second-order Nonlinear Optical Properties of Substituted Thiazole DerivativesCHINESE JOURNAL OF CHEMISTRY, Issue 4 2001Yong-Jun Liu Abstract On the basis of ZINDO program, we have designed a program to calculate the nonlinear second-order polarizability ,yk and ,, according to the SOS expression. The second-order nonlinear optical properties of 4-nitro-4,-dimethylamino-stilbene and a series of its thiazole derivatives were studied. The calculated results were that: When replacing a benzene ring in 4-nitro-4,-dimethylamino-stilbene by a thiazole ring, the influence on , values depends on the position of thiazole ring. When the thiazole ring connects with nitro group (acceptor), the , values increase significantly compared with corresponding stilbene derivatives. The , values of 2-(p -donor-,-styryl)-5-nitro-thiazole derivatives (2,7) are larger than those of 2-(p -nitro-,-styryl)-5-donor-thiazole derivatives (8,13) and 2-(p -donor-phenyl)-azo-5-nitro-thiazole derivatives (14,19). The 2-(p -donor-,-styryl)-5-nitro-thiazole derivatives (2,7) are good candidates as chromophores duo to their high nonlinearities and potential good thermal stability. [source] | |||||||||||||