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Latter Compound (latter + compound)
Selected AbstractsThe uptake by cells of 2-arachidonoylglycerol, an endogenous agonist of cannabinoid receptorsFEBS JOURNAL, Issue 7 2001Tiziana Bisogno It is not yet clear if the endocannabinoid 2-arachidonoylglycerol (2-AG) is transported into cells through the same membrane transporter mediating the uptake of the other endogenous cannabinoid, anandamide (N -arachidonoylethanolamine, AEA), and whether this process (a) is regulated by cells and (b) limits 2-AG pharmacological actions. We have studied simultaneously the facilitated transport of [14C]AEA and [3H]2-AG into rat C6 glioma cells and found uptake mechanisms with different efficacies but similar affinities for the two compounds (Km 11.0 ± 2.0 and 15.3 ± 3.1 µm, Bmax 1.70 ± 0.30 and 0.24 ± 0.04 nmol·min,1·mg protein,1, respectively). Despite these similar Km values, 2-AG inhibits [14C]AEA uptake by cells at concentrations (Ki = 30.1 ± 3.9 µm) significantly higher than those required to either 2-AG or AEA to inhibit [3H]2-AG uptake (Ki = 18.9 ± 1.8 and 20.5 ± 3.2 µm, respectively). Furthermore: (a) if C6 cells are incubated simultaneously with identical concentrations of [14C]AEA and [3H]2-AG, only the uptake of the latter compound is significantly decreased as compared to that observed with [3H]2-AG alone; (b) the uptake of [14C]AEA and [3H]2-AG by cells is inhibited with the same potency by AM404 (Ki = 7.5 ± 0.7 and 10.2 ± 1.7 µm, respectively) and linvanil (Ki = 9.5 ± 0.7 and 6.4 ± 1.2 µm, respectively), two inhibitors of the AEA membrane transporter; (c) nitric oxide (NO) donors enhance the uptake of both [14C]AEA and [3H]2-AG, thus suggesting that 2-AG action can be regulated through NO release; (d) AEA and 2-AG induce a weak release of NO that can be blocked by a CB1 cannabinoid receptor antagonist, and significantly enhanced in the presence of AM404 and linvanil, thus suggesting that transport into C6 cells limits the action of both endocannabinoids. [source] A study of the mechanisms of divalent copper binding to a modified cellulose adsorbentJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010David William O'Connell Abstract A modified cellulose material was prepared by grafting glycidyl methacrylate to cellulose (Cell- g -GMA) with subsequent functionalization with imidazole (Cell- g -GMA-imidazole). This latter compound was used in the adsorption of copper from aqueous solution. The mechanism of Cu(II) binding onto the cell- g -GMA-imidazole was investigated at the molecular level using scanning electron microscopy (SEM), Fourier transform infrared (FTIR), x-ray photoelectron spectroscopy (XPS), energy dispersive x-ray analysis (EDX) and X-ray diffraction (XRD). FTIR and Raman spectroscopy provided an insight into the extent to which perturbation of the imidazole ring occurred following adsorption of the metal while XPS spectra indicated the binding of Cu(II) ions to nitrogen atoms by the appearance of additional binding energy peaks for nitrogen on the cellulose- g -GMA-imidazole sample post adsorption. The EDX technique provided clear evidence of the physical presence of both the copper and sulfate on the cellulose- g -GMA-imidazole material post adsorption. XRD analysis further confirmed the presence of a copper species in the adsorbent material as copper sulfate hydroxide (Cu3(OH)4SO4 - antlerite). The XRD studies further suggest that the overall extent of Cu(II) adsorption is not alone a combination of true metal chelation as suggested by FTIR, Raman and XPS, but also a function of surface precipitation of the polynuclear copper species. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Characterisation of indomethacin and nifedipine using variable-temperature solid-state NMRMAGNETIC RESONANCE IN CHEMISTRY, Issue 11 2005David C. Apperley Abstract We have characterised the stable polymorphic forms of two drug molecules, indomethacin (1) and nifedipine (2) by 13C CPMAS NMR and the resonances have been assigned. The signal for the CCl carbon of indomethacin has been studied as a function of applied magnetic field, and the observed bandshapes have been simulated. Variable-temperature 1H relaxation measurements of static samples have revealed a T1, minimum for indomethacin at 17.8 °C. The associated activation energy is 38 kJ mol,1. The relevant motion is probably an internal rotation and it is suggested that this involves the COCH3 group. Since the two drug compounds are potential candidates for formulation in the amorphous state, we have examined quench-cooled melts in detail by variable-temperature 13C and 1H NMR. There is a change in slope for and at the glass transition temperature (Tg) for indomethacin, but this occurs a few degrees below Tg for nifedipine, which is perhaps relevant to the lower real-time stability of the amorphous form for the latter compound. Comparison of relaxation time data for the crystalline and amorphous forms of each compound reveals a greater difference for nifedipine than for indomethacin, which again probably relates to real-time stabilities. Recrystallisation of the two drugs has been followed by proton bandshape measurements at higher temperatures. It is shown that, under the conditions of the experiments, recrystallisation of nifedipine can be detected already at 70 °C, whereas this does not occur until 110 °C for indomethacin. The effect of crushing the amorphous samples has been studied by 13C NMR; nifedipine recrystallises but indomethacin does not. The results were supported by DSC, powder XRD, FTIR and solution-state NMR measurements. Copyright © 2005 John Wiley & Sons, Ltd. [source] Non-empirical calculations of NMR indirect carbon,carbon coupling constants.MAGNETIC RESONANCE IN CHEMISTRY, Issue 6 2003Part 4: Bicycloalkanes Abstract A systematic study of the one-bond and long-range J(C,C), J(C,H) and J(H,H) in the series of nine bicycloalkanes was performed at the SOPPA level with special emphasis on the coupling transmission mechanisms at bridgeheads. Many unknown couplings were predicted with high reliability. Further refinement of SOPPA computational scheme adjusted for better performance was carried out using bicyclo[1.1.1]pentane as a benchmark to investigate the influence of geometry, basis set and electronic correlation. The calculations performed demonstrated that classical ab initio SOPPA applied with the locally dense Dunning's sets augmented with inner core s-functions used for coupled carbons and Sauer's sets augmented with tight s-functions used for coupled hydrogens performs perfectly well in reproducing experimental values of different types of coupling constants (the estimated reliability is ca 1,2 Hz) in relatively large organic molecules of up to 11 carbon atoms. Additive coupling increments were derived for J(C,C), J(C,H) and J(H,H) based on the calculated values of coupling constants within SOPPA in the model bicycloalkanes, in reasonably good agreement with the known values obtained earlier on pure empirical grounds. Most of the bridgehead couplings in all but one bicycloalkane appeared to be essentially additive within ca 2,3 Hz while bicyclo[1.1.1]pentane demonstrated dramatic non-additivity of ,14.5 Hz for J(C,C), +16.6 Hz for J(H,H) and ,5.5 Hz for J(C,H), in line with previous findings. Non-additivity effects in the latter compound established at the SOPPA level should be attributed to the through-space non-bonded interactions at bridgeheads due to the essential overlapping of the bridgehead rear lobes which provides an additional and effective non-bonding coupling path for the bridgehead carbons and their protons in the bicyclopentane framework. Copyright © 2003 John Wiley & Sons, Ltd. [source] Characterization of the pressure-induced second-order phase transition in the mixed-valence vanadate BaV6O11ACTA CRYSTALLOGRAPHICA SECTION B, Issue 3 2009Karen Friese The pressure dependence of the structure of the mixed-valence vanadate BaV6O11 was studied with single-crystal X-ray diffraction in a diamond,anvil cell. The compressibility data could be fitted with a Murnaghan equation of state with the zero-pressure bulk modulus B0 = 161,(7),GPa and the unit-cell volume at ambient pressure = 387.1,(3),Å (B, = 4.00). A phase transition involving a symmetry reduction from P63/mmc to P63mc can be reliably detected in the high-pressure data. The estimated transition pressure lies in the range 1.18,<,Pc,<,3.09,GPa. The transition leads to a breaking of the regular Kagomé net formed by part of the V ions. While in the ambient pressure structure all V,V distances in the Kagomé net are equal, they split into inter-trimer and intra-trimer distances in the high-pressure phase. In general, these changes are comparable to those observed in the corresponding low-temperature transition. However, the pressure-induced transition takes place at a lower unit-cell volume compared with the temperature-induced transition. Furthermore, overall trends for inter-trimer and intra-trimer V,V distances as a function of the unit-cell volume are clearly different for datapoints obtained by variation of pressure and temperature. The behavior of BaV6O11 is compared with that of NaV6O11. While in the latter compound the transition can be explained as a pure volume effect, in BaV6O11 an additional degree of freedom related to the valence distribution among the symmetrically independent vanadium sites has to be taken into account. [source] Synthesis of new 3-(trifluoromethyl)-1H -indoles by reduction of trifluoromethyloxoindolesJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 4 2008Moônica M. Bastos This work describes the synthesis of new 3-trifluoromethylindoles. Different isatins were trifluoromethylated using (trifluoromethyl) trimethylsilane (Me3SiCF3) as a nucleophilic agent giving new 3-hydroxy-3-(trifluoromethyl)indolin-2-one. Different "one-step" procedures to transform the latter compounds into the reduced indoles were attempted, but failed. For the synthesis of the new trifluoromethylindoles the corresponding 2-oxo-3-(trifluoromethyl)indoles were reduced using borane/THF complex to furnish 3-(trifluoromethyl)indolin-3-ol that additionally were dehydrated using thionyl chloride in pyridine to give excellent yields of the desired products. [source] The Interaction of Heteroaryl-Acrylates and Alanines with Phenylalanine Ammonia-Lyase from ParsleyCHEMISTRY - A EUROPEAN JOURNAL, Issue 10 2006Csaba Paizs Dr. Abstract Acrylic acids and alanines substituted with heteroaryl groups at the ,-position were synthesized and spectroscopically characterized (UV, HRMS, 1H NMR, and 13C NMR spectroscopy). The heteroaryl groups were furanyl, thiophenyl, benzofuranyl, and benzothiophenyl and contained the alanyl side chains either at the 2- or 3-positions. While the former are good substrates for phenylalanine ammonia-lyase (PAL), the latter compounds are inhibitors. Exceptions are thiophen-3-yl-alanine, a moderate substrate and furan-3-yl-alanine, which is inert. Possible reasons for these exceptions are discussed. Starting from racemic heteroaryl-2-alanines their D -enantiomers were prepared by using a stereodestructive procedure. From the heteroaryl-2-acrylates, the L -enantiomers of the heteroaryl-2-alanines were prepared at high ammonia concentration. These results can be best explained by a Friedel,Crafts-type electrophilic attack at the aromatic part of the substrates as the initial step of the PAL reaction. [source] Toxicity and Synergism in the Feeding Deterrence of Some Coumarins on Spodoptera frugiperdaSmith (Lepidoptera: Noctuidae)CHEMISTRY & BIODIVERSITY, Issue 1 2006Nancy Vera Abstract The phagodepression activity of five coumarins (=2H -1-benzopyran-2-ones), 6-hydroxy-7-isoprenyloxycoumarin (1), 6-methoxy-7-isoprenyloxycoumarin (2), 6,7-methylenedioxycoumarin (3), 5-methoxy-6,7-methylenedioxycoumarin (4), and 6-methoxy-7-(2-hydroxyethoxy)coumarin (5), from the Argentine native herb Pterocaulon polystachyum, was tested against Spodoptera frugiperda (Lepidoptera: Noctuidae) larvae. Two analogs, scopoletin (6) and 2-methoxy-2-methyl-3,4,5,6,7,8-hexahydro-3H -chromen-5-one (7), synthesized in our laboratory, were also evaluated for comparison. The compounds were added to an artificial diet at doses ranging from 50 to 200,,g per g of diet. Natural coumarins induced 100% of phagodepression when 200,,g were added per g of diet. Binary equimolar mixtures of the natural coumarins were phagodepressors against S. frugiperda surpassing the expected additive responses, indicating that these compounds can act synergistically against S. frugiperda larvae. Compounds 1 and 3 (non-methoxylated coumarins), and the equimolar mixture of both, displayed the strongest phagodepression. Additionally, 50,,g/g of 1 and 3 incorporated to the larval diet caused 80 and 50% of pupal mortality, respectively, while a 100,,g/g dose of compounds 2, 4, 6, and 7 produced 60, 50, 10, and 80% pupal mortality, respectively. Larval growing rate during the early larval instars was significantly reduced by treatments with the methylenedioxycoumarins 3 and 4. Coincidentally, the larval period duration was significantly increased by the latter compounds. [source] | ||||||||||