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111.
Boris M. Mandić Dejan M. Gođevac Ljubodrag V. Vujisić Snežana S. Trifunović Vele V. Tesević Vlatka V. Vajs Slobodan M. Milosavljević 《Chemical Papers》2011,65(1):90-92
In this paper, examination of the aerial parts of seven Senecio species from Serbia and Montenegro is reported. Phytochemical investigation of Senecio erucifolius led to the isolation and characterization of semiquinol butyl 2-(1-hydroxy-4-oxocyclohexa-2,5-dienyl)acetate (I), along with methyl 2-(1-hydroxy-4-oxocyclohexa-2,5-dienyl)acetate (jacaranone, II), and methyl 2-(4-hidroxyphenyl)acetate (III). The structure of I was established based on spectroscopic studies (1H- and 13C-NMR, IR, and CI-MS). Compound II was also isolated from S. carpathicus and S. subalpinus. The presence of jacaranone in the methanol extracts of S. wagneri, S. othonnae, and S. paludosus was confirmed by LC/ESI-TOF MS. 相似文献
112.
Sylvain Maclot Michael Capron Rémi Maisonny Arkadiusz Ławicki Dr. Alain Méry Dr. Jimmy Rangama Prof. Dr. Jean‐Yves Chesnel Sadia Bari Prof. Dr. Ronnie Hoekstra Dr. Thomas Schlathölter Prof. Dr. Bruno Manil Prof. Dr. Lamri Adoui Dr. Patrick Rousseau Prof. Dr. Bernd A. Huber 《Chemphyschem》2011,12(5):881-881
113.
The semicontinuous emulsion polymerization of vinyl acetate has been studied. Poly(vinyl alcohol) as a protective colloid and ethoxylated cetyl alcohol as a coemulsifier were used. The conversion and particle diameter were affected by the stirring speed and the coemulsifier distribution between initial reactor charge and continuously introduced monomer. The amount of unreacted monomer oscillates with time. 相似文献
114.
Maciej Makowski Krzysztof Pawełczak Paweł Kafarski Jolanta M. Dzik Barbara Gołos Małgorzata Balinska 《Phosphorus, sulfur, and silicon and the related elements》2013,188(8):1639-1651
The synthesis of six analogues of the potent thymidylate synthase (TS) inhibitor N -[4-[ N -[(3,4-dihydro-2-methyl-4-oxo-6-quinazolinoyl)-methyl]- N -prop-2-ynylamino]benzoyl]- L -glutamic acid 2 is described in which the glutamic acid residue has been replaced by DL -aminophosphonic acids. New antifolates were tested as inhibitors of TS isolated from mouse L1210 leukemic cells as well as inhibitors of growth mouse leukemic L5178Y cells. In general these modifications result in compounds that are considerably less potent than 2 as TS inhibitors with K i 's 0.17-1.10 w M. Very poor solubility in water limited their proper assay of growth cells inhibition. 相似文献
115.
Pierre Thuéry Nelly Keller Monique Lance Julien-Daniel Vigner Martine Nierlich 《Journal of inclusion phenomena and macrocyclic chemistry》1994,20(1):89-96
The doubly deprotonated form of calix[6]arene, with two protonated triethylamines as counter-ions, crystallizes in the monoclinic system: space groupP21/n,a=8.465(4),b=17.822(8),c=15.182(6) Å,=90.18(4)°,V=2291(2) Å3,Z=2. Refinement led to a final conventionalR value of 0.063 for 1046 reflections. The macrocycle conformation is not apinched cone, usual for freeR-calix[6]arene, but a distorted 1,2,3-alternate cone, since the molecule lies on a symmetry center. Furthermore, one of the torsion angles defined by the methylene bridges is near to zero, which is unusual in calixarene structures.
Supplementary Data relating to this article (atomic coordinates for hydrogen atoms, anisotropic displacement parameters for oxygen and nitrogen atoms, and observed and calculated structure factors) are deposited with the British Library as Supplementary Publication No. SUP 82182 (7 pages). 相似文献
116.
Treatment of the uranium(IV) complexes [{ML1(py)}2UIV] (M = Cu, Zn; L1 = N,N′-bis(3-hydroxysalicylidene)-1,3-propanediamine) with silver nitrate in pyridine led to the formation of the corresponding cationic uranium(V) species which were found to be thermally unstable and were converted back into the parent UIV complexes; no electron transfer was observed in solution between the UIV and UV compounds. In the crystals of [{ML1(py)}2UIV][{ML1(py)}2UV][NO3], the neutral UIV and cationic UV species are clearly identified by the distinct U–O distances. Similar reaction of [{ZnL2(py)}2UIV] [L2 = N,N′-bis(3-hydroxysalicylidene)-1,4-butanediamine] with AgNO3 gave crystals of [{ZnL2(py)}UV{ZnL2(py)2}][NO3] but the copper counterpart was not isolated. Crystals of [{ZnL1(py)}2UV][OTf] · THF (OTf = OSO2CF3) were obtained fortuitously from the reaction of [Zn(H2L1)] and U(OTf)3. 相似文献
117.
Dr. Gaëlle Charron Dr. Elena Malkin Dr. Guillaume Rogez Dr. Luke J. Batchelor Dr. Sandra Mazerat Dr. Régis Guillot Dr. Nathalie Guihéry Dr. Anne‐Laure Barra Dr. Talal Mallah Dr. Hélène Bolvin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(47):16850-16862
By using complementary experimental techniques and first‐principles theoretical calculations, magnetic anisotropy in a series of five hexacoordinated nickel(II) complexes possessing a symmetry close to C2v, has been investigated. Four complexes have the general formula [Ni(bpy)X2]n+ (bpy=2,2′‐bipyridine; X2=bpy ( 1 ), (NCS?)2 ( 2 ), C2O42? ( 3 ), NO3? ( 4 )). In the fifth complex, [Ni(HIM2‐py)2(NO3)]+ ( 5 ; HIM2‐py=2‐(2‐pyridyl)‐4,4,5,5‐tetramethyl‐4,5‐dihydro‐1H‐imidazolyl‐1‐hydroxy), which was reported previously, the two bpy bidentate ligands were replaced by HIM2‐py. Analysis of the high‐field, high‐frequency electronic paramagnetic resonance (HF‐HFEPR) spectra and magnetization data leads to the determination of the spin Hamiltonian parameters. The D parameter, corresponding to the axial magnetic anisotropy, was negative (Ising type) for the five compounds and ranged from ?1 to ?10 cm?1. First‐principles SO‐CASPT2 calculations have been performed to estimate these parameters and rationalize the experimental values. From calculations, the easy axis of magnetization is in two different directions for complexes 2 and 3 , on one hand, and 4 and 5 , on the other hand. A new method is proposed to calculate the g tensor for systems with S=1. The spin Hamiltonian parameters (D (axial), E (rhombic), and gi) are rationalized in terms of ordering of the 3 d orbitals. According to this orbital model, it can be shown that 1) the large magnetic anisotropy of 4 and 5 arises from splitting of the eg‐like orbitals and is due to the difference in the σ‐donor strength of NO3? and bpy or HIM2‐py, whereas the difference in anisotropy between the two compounds is due to splitting of the t2g‐like orbitals; and 2) the anisotropy of complexes 1 – 3 arises from the small splitting of the t2g‐like orbitals. The direction of the anisotropy axis can be rationalized by the proposed orbital model. 相似文献
118.
Ynamides react with various azides in the ruthenium-catalyzed Huisgen [3+2] cycloaddition reaction. This ruthenium-catalyzed azide-ynamide cycloaddition reaction yields 1-protected 5-amido 1,2,3-triazoles. 相似文献
119.
120.
Becerril R Gómez-Lus R Goñi P López P Nerín C 《Analytical and bioanalytical chemistry》2007,388(5-6):1003-1011
The aim of this work is the optimization and application of a group of analytical and microbiological techniques in the study
of the activity of essential oils (EOs) incorporated in a new antimicrobial packaging material and the research in depth of
the interaction between the microbial cells and the individual compounds present in the active material. For this purpose
the antimicrobial activity of the active packaging containing cinnamon or oregano was evaluated against E. coli and S. aureus. The vapour phase activity and the direct contact between the antimicrobial agents themselves, or once incorporated in the
packaging material, and the microbial cells have been studied. The direct contact was studied using a broth dilution method.
The vapour phase was evaluated by using a new method which involves the use of a filter disk containing the EOs. Furthermore,
the kill time assay was used to determine the exposure time for the maximum efficiency in packaging, and transmission electron
microscopy was used to investigate the antimicrobial activity and the possible mechanism of action against E. coli and S. aureus. Finally, the compounds absorbed by cells were identified. The results showed that the techniques used provide relevant information
about the antibacterial activity of cinnamon and oregano in direct contact as well as in the vapour phase. The antimicrobial
packaging showed a fast efficiency which supports its likely application as a food packaging material. Bacteria treated with
EOs exhibit a wide range of significant abnormalities; these include formation of blebs, coagulation of cytoplasmatic constituents,
collapse of the cell structure and lack of cytoplasmatic material. Some of these observations are correlated to the ability
of some of these substances to disrupt envelop structure, especially the inner membrane. After an extraction from dead cells,
cinnamaldehyde was detected by GC-MS in E. coli exposed to the active packaging containing cinnamon. 相似文献