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51.
Fontana José D. Almeida Eduardo R. A. Baron Madalena Guimaraes Manoel F. Deschamps Francisco C. Schwartsmann Gllberto Cervi Armando C. Zanette Flávio Vilegas Janete LanÇas Fernando M. 《Applied biochemistry and biotechnology》1994,(1):295-313
The acetogenins are strongly bioactive natural compounds present in the bark, roots, leaves, and seeds of manyAnnonaceae plants. They are modified fatty acids and their cytotoxicities have been determined for different biological models including
the in vitro growth inhibition of several human cancer cell lines.
Very low acetogenin yield (< 0.1 g%) has been found previously in native phytobiomass, and we have now investigated the nonpredatory
exploitation of the seeds as acetogenin sources characterizing the seed triacylglycerols (dominant fraction; > 90% of the
whole lipid extracts) as potential valuable by-products. 相似文献
52.
Makarycheva-Mikhailova AV Kukushkin VY Nazarov AA Garnovskii DA Pombeiro AJ Haukka M Keppler BK Galanski M 《Inorganic chemistry》2003,42(8):2805-2813
The reaction between the platinum(IV) complex trans-[PtCl(4)(EtCN)(2)] and the amino alcohols NH(2)CH(2)CH(2)OH, NH(2)CH(2)CH(Me)OH-(R)-(-), NH(2)CH(Ph)CH(2)OH-(R)-(-), NH(2)CH(Et)CH(2)OH-(R)-(-), NH(2)CH(Et)CH(2)OH-(S)-(+), and NH(2)CH(Pr(n)())CH(2)OH proceeds rapidly at room temperature in CH(2)Cl(2) to furnish the amidine complexes [PtCl(4)(HN=C(Et)NH(arcraise;)OH)(2)] (1-6) in good yield (70-80%). The related reaction between the platinum(II) complex trans-[PtCl(2)(EtCN)(2)] and monoethanolamine in a molar ratio of 1:2 in CH(2)Cl(2) results in the addition of 4 equiv of NH(2)CH(2)CH(2)OH per mole of complex to give [Pt(HN=C(Et)NHCH(2)CH(2)OH)(2)(NH(2)CH(2)CH(2)OH)(2)](2+) (7). Formulation of 1-6 is based upon satisfactory C, H, N elemental analyses, electrospray mass spectrometry, IR spectroscopy, and (1)H, (13)C((1)H), (15)N, and (195)Pt NMR spectroscopies, while the structures of trans-[PtCl(4)((Z)-NH=C(Et)NHCH(2)CH(2)OH)(2)] (1), trans-[PtCl(4)((Z)-NH=C(Et)NHCH(2)CH(Me)OH-(R)-(-))(2)] (2), and trans-[PtCl(4)((Z)-NH=C(Et)NHCH(Et)CH(2)OH-(R)-(-))(2)] (4) were determined by X-ray single-crystal diffraction. The Z-amidine configuration of the ligands is preserved in CDCl(3) solutions as confirmed by gradient-enhanced (15)N,(1)H-HMQC spectroscopy and NOE experiments. The amidines, formed upon Pt(IV)-mediated nitrile-amino alcohol coupling, were liberated from their platinum(IV) complexes 1, 3, and 4 by reaction with Ph(2)PCH(2)CH(2)PPh(2) (dppe) giving free NH=C(Et)NHCHRCH(2)OH (R = H 8, Et 9, Ph 10), with the substituents R of different types, and dppe oxides; the P-containing species were identified by (31)P((1)H) NMR spectroscopy. NOESY spectroscopy indicates that the liberated amidines retained the same configuration relative to the C=N double bond, i.e., syn-(H,Et)-NH=C(Et)NHCHRCH(2)OH. The liberated hydroxo-functionalized amidines 8-10 were converted into oxazolines (11-13) in the presence of a catalytic amount of ZnCl(2). A similar catalytic effect has also been reached using anhydrous MSO(4) (M = Cu, Co, Cd), CdCl(2), and AlCl(3). 相似文献
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Inês Nunes Nuno Mesquita Sandra Cabo Verde Maria João Trigo Armando Ferreira Maria Manuela Carolino António Portugal Maria Luísa Botelho 《Radiation Physics and Chemistry》2012,81(12):1943-1946
Parchments are important documents that give testimony for History; therefore these materials should be respected and preserved. Considering incremental biodeterioration problems that have to be faced daily, the Archive of the University of Coimbra (AUC) is involved in different scientific projects in order to evaluate and determine new methods for document decontamination and preservation.The aim of this study was to evaluate gamma radiation effects on the colour and texture of the AUC parchment documents. The assessment of these effects was used to estimate the maximum gamma radiation dose (Dmax) that could guarantee parchment documents′ decontamination treatment, without significant alteration of their physical properties. Parchment samples were exposed to gamma radiation doses ranging from 10 to 30 kGy. The texture and colour of samples were assessed before and after the irradiation procedure, using a texture analyser and an electronic colorimeter. Hardness and springiness were determined based on texture spectra. Lightness (L?), Chroma (C), greenness vs. redness (a*) and yellowness vs. blueness (b*) values were obtained from colorimetric measures. Results indicate no significant effects of gamma radiation on the texture and colour of parchment for the studied doses. 相似文献
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The sesquiterpene (+)-gossonorol is prepared in only three synthetic steps in 60% overall yield and 82% ee from commercially available reagents. The key asymmetric step is the catalytic enantioselective addition of dimethylzinc to 5-methyl-1-(2-methylphenyl)hex-4-en-1-one catalyzed by chiral isoborneolsulfonamide ligands in the presence of titanium tetraisopropoxide. The modular approach allows the synthesis not only of the aforementioned natural product but also other products arising from the corresponding processes of ethylation, phenylation, and ethynylation, just by changing the final nucleophilic reagent and using the same isoborneol type ligand. 相似文献
58.
Diego Lomonaco Francisco Jonas Nogueira Maia Selma Elaine Mazzetto 《Journal of Thermal Analysis and Calorimetry》2013,111(1):619-626
In this study, the thermal-oxidative stability of poly(methyl methacrylate), PMMA, 1 % additivated with replenishable phenolic lipids is evaluated by thermogravimetric (TG/DTG) analyses and differential scanning calorimetry (DSC) analyses. Since technical cashew nutshell liquid (CNSL), a byproduct from the cashew industry, is composed basically of two phenolic lipids, cardanol and cardol, the utilization of this industrial waste and its main components as a new source of bioadditives for use as antioxidants is evaluated. The TG analyses revealed that addition of the phenolic constituent of CNSL increased the thermal stability of PMMA films considerably. The results obtained were also confirmed by DSC analyses. 相似文献
59.
Mira Abdallah Diego Magaldi Akram Hijazi Bernadette Graff Frdric Dumur Jean‐Pierre Fouassier Thanh‐Tun Bui Fabrice Goubard Jacques Laleve 《Journal of polymer science. Part A, Polymer chemistry》2019,57(20):2081-2092
In this article, new compounds based on the carbazole scaffold (DMs = DM1 and DM2, constituted by a carbazole unit connected on positions 3 and 6 to a two 4,4′‐dimethoxydiphenylamine groups and differing by the substituent present on the nitrogen heteroatom of the carbazole core) were synthesized and proposed as high‐performance visible light photoinitiators/photosensitizers for both the free‐radical polymerization of methacrylates and the cationic polymerization of epoxides upon visible light exposure using LED@405 nm. Remarkably, DM2 leads to higher final conversions than DM1. In order to study the photophysical and photochemical properties of the carbazole derivatives, different parameters were taken into account such as the light absorption, the steady‐state photolysis, and the fluorescence spectroscopy. Using different techniques such as fluorescence quenching, redox behavior, and cyclic voltammetry, we are able to discuss the photosensitization/photoinitiation reactions providing a full coherent picture of the involved chemical mechanisms. The photosensitization of the carbazole derivatives occurred predominantly via singlet excited states at the rate of the diffusion limit. Upon exposure to laser diode at 405 nm, DMs show high performance in initiating systems for 3D resins. Remarkably, DM2 can also be used in photocomposite synthesis using light‐emitting diode conveyor. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2081–2092 相似文献
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