Search results for "medicinal"
showing 10 items of 2966 documents
Cytotoxic glycosides from the roots of Weigela x “Bristol Ruby”
2019
International audience; Seven oleanane-type glycosides were extracted and isolated by various chromatographic methods from the roots of Weigela x "Bristol Ruby" (1-7), six previously undescribed (1-6) and a known one (7). Their structures were assigned by spectroscopic analysis mainly 2D NMR and mass spectrometry (ESIMS). Selected triterpenoid glycosides (1-3, 6, 7) displayed a good cytotoxic activity against a mouse colon cancer cell line CT26.
Hydrogenation of White Phosphorus to Phosphane with Rhodium and Iridium Trihydrides.
1998
Only one of the four P atoms of P4 reacts with rhodium and iridium trihydrides [(triphos)MH3 ] to provide phosphane [Eq. (a)]. The resulting cyclo-P3 fragment is efficiently scavenged by the metal fragment to give the complexes [(triphos)M(η3 -P3 )]. A mechanism accounting for the hydrogenation reaction is proposed in which the complexes [(triphos)MH(η1 :η1 -P4 )] and [(triphos)M(η1 :η2 -HP4 ] are intermediates. The latter complex contains the unprecedented hydridotetraphosphane ligand HP4- .
Preparation and XAFS studies of organotin(IV) complexes with adenosine and related compounds and calf thymus DNA
2007
Complexes of adenosine and related compounds (adenosine-5’-monophosphate, adenosine-5’-triphosphate and pyridoxal-5-phosphate) with Bu2SnO and/or BuSnCl2 were prepared in the solid state. The compositions of the complexes were determined by standard analytical methods. It was found that the complexes contain the organotin(IV) moiety and the ligand in a ratio of 1:1. The FT-IR spectra demonstrated that Bu2SnO reacts with the D-ribose moiety of the ligands, while Bu2SnCl2 is coordinated to the deprotonated phosphate group. The basic part of the ligands does not participate directly in complex formation. Comparison of the experimental Mossbauer Δ (quadrupole splitting) values with those calcul…
Methyl 3,3,6,6-tetramethyl-1,8-dioxo-4,5,7,9-tetrahydro-2H-xanthene-9-carboxylate
2020
The title molecule, C19H24O5, is built by annulation of a half-chair cyclohexenone and a twist-cyclohexenone to a flat 4-H-pyrane boat. In the crystal, molecules are connected via van der Waals interactions and C—H...O hydrogen bonds.
Macrocyclic hexaureas: synthesis, conformation, and anion binding.
2009
Varied flexibility: Cyclic oligoureas are formed by using anions as templates. Linking of six xanthene and/or diphenyl ether fragments by urea groups leads to the formation of five macrocyclic compounds with a 48-membered ring with variable flexibility (see picture). Their interaction with anions shows a strong influence of acetate and chloride ions on the cyclization from four precursor molecules. Five macrocylic compounds XXXXXX, XXDXXD, XDXDXD, XDDXDD, and DDDDDD with 48-membered rings, in which six xanthene and/or diphenyl ether fragments are linked through six urea (-NH-C(O)-NH-) groups, have been synthesized. In the cyclization step, a linear diamine was allowed to react with the appr…
[Cu(P^P)(N^N)][PF6] compounds with bis(phosphane) and 6-alkoxy, 6-alkylthio, 6-phenyloxy and 6-phenylthio-substituted 2,2'-bipyridine ligands for lig…
2018
We report a series of [Cu(P^P)(N^N)][PF6] complexes with P^P = bis(2-(diphenylphosphino)phenyl)ether (POP) or 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (xantphos) and N^N = 6-methoxy-2,2′-bipyridine (MeObpy), 6-ethoxy-2,2′-bipyridine (EtObpy), 6-phenyloxy-2,2′-bipyridine (PhObpy), 6-methylthio-2,2′-bipyridine (MeSbpy), 6-ethylthio-2,2′-bipyridine (EtSbpy) and 6-phenylthio-2,2′-bipyridine (PhSbpy). The single crystal structures of all twelve compounds have been determined and confirm chelating modes for each N^N and P^P ligand, and a distorted tetrahedral geometry for copper(I). For the xantphos-containing complexes, the asymmetrical bpy ligand is arranged with the 6-substituent lying …
2,7-Di-tert-butyl-9,9-dimethyl-4,5-bis(4-tritylanilinocarbonyl)-9H-xanthene methanol trisolvate monohydrate
2006
The title compound, C75H68N2O3·3CH3OH·H2O, was synthesized starting from the corresponding acid and p-tritylaniline. Single crystals were obtained from a methanol solution as a solvate, with three methanol molecules and one water molecule. The solid-state structure proves the existence of an intramolecular bifurcated hydrogen bond between one amide H atom and the carbonyl and xanthene O atoms. The packing is stabilized by intermolecular hydrogen bonds.
Competitive and Selective Csp3Br versus Csp2Br Bond Activation in Palladium-Catalysed Suzuki Cross-Coupling: An Experimental and Theoretical Study …
2010
Phosphine ligands have been demonstrated to have an effect on reactivity and selectivity in the competitive intramolecular palladium-catalysed Suzuki-Miyaura coupling of dibromo sulfoxide 1a possessing two different hybridised electrophilic carbons. It was found that the bromine bond to the sp(3)-hybridised carbon is selectively replaced in the presence of unhindered phosphines such as PPh(3) or xantphos. The use of hindered phosphine ligands such as P(o-tol)(3) and P(1-naphthyl)(3) reversed the selectivity, conducting the cross-coupling at the Csp(2)-Br. Identical trends were observed in external competition experiments carried out with bromomethyl sulfoxide and different substituted bromo…
Mercury in fish products: what’s the best for consumers between bluefin tuna and yellowfin tuna?
2017
A total of 205 bluefin and yellowfin tuna samples were examined for mercury detection in order to verify possible differences and have a detailed risk assessment of the two tuna species. The results showed significant higher mercury concentration in muscle tissue of bluefin tuna respect yellowfin tuna (p < 0.001) with mean concentration of 0.84 mg/kg and maximum value of 1.94 mg/kg. These differences can be due the different biological and ecological aspects of the two tuna species and to different oceanographic aspects between Atlantic Ocean and Mediterranean sea. The results obtained in this study suggest an advisable containment of the sources of pollution and further studies on the c…
Synthesis of bis(diphenylphosphinocyclopentadienyl) yttrium chloride complexes and heterodimetallic derivatives. X-ray structure of bis[(μ-chloro)bis…
1996
Abstract Reaction of lithium diphenylphosphinocyclopentadienide with YCl 3 or YCl 3 (THF) 3 and working lead to the formation of three yttrocene phosphines: the lithium metal adduct isolated as (Ph 2 PC 5 H 4 ) 2 Y(μ-Cl) 2 Li(THF) 2 · 0.5 LiCl ( 1 ), the chloride-bridged dimeric species {(Ph 2 PC 5 H 4 ) 2 Y(μ-Cl)} 2 ( 2 ), and the coordinated monometal species [(Ph 2 PC 5 H 4 ) 2 YCl(THF)] ( 3 ). The X-ray structure of 2 is remarkable in that the crystal exhibits two independent chloride-bridged dimers that differ in the arrangement ( syn, anti ) of the diphenylphosphino groups. Chelation of phosphorus atoms to a molydenum carbonyl moiety is also reported.