共查询到20条相似文献,搜索用时 31 毫秒
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In the present study, Quantitative Structure-Activity Relationship (QSAR) modeling has been carried out for lipid peroxidation
(LPO)-inhibition potential of a set of 27 flavonoids, using structural and topological parameters. For the development of
models, three methods were used: (1) stepwise regression, (2) factor analysis followed by multiple linear regressions (FA-MLR)
and (3) partial least squares (PLS) analysis. The best equation was obtained from stepwise regression analysis (Q2 = 0.626) considering the leave-oneout prediction statistics.
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5.
Gheorghe Roman 《Central European Journal of Chemistry》2012,10(5):1516-1526
Benzimidazole, benzimidazoles diversely substituted at position 2, and 5,6-dimethylbenzimidazole have been alkylated at N
1 with ketonic Mannich bases derived from acetophenones, acetylnaphthalenes, 2-acetylthiophene and 1-tetralone to afford a
series of novel 1-(3-oxopropyl)benzimidazoles. The reduction of these transamination products with NaBH4 in methanol produced the corresponding 1-(3-hydroxypropyl)benzimidazoles in excellent yields.
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6.
Liquid-liquid partition is used in sample preparation and in countercurrent and liquid-liquid chromatographic separations.
Partition coefficients are widely used in toxicology, environmental, and analytical chemistry. The K
hn
determination procedure for the n-hexane/nitromethane system was optimized and partition coefficients for 99 ketones, esters and trimethylsilyl derivatives
of phenols, aliphatic and aromatic acids were determined. For 130 compounds, K
hn
values were predicted using mathematical relationships between K
hn
and other physicochemical and structural parameters.
相似文献
7.
Sandip A. Sadaphal Kiran F. Shelke Swapnil S. Sonar Murlidhar S. Shingare 《Central European Journal of Chemistry》2008,6(4):622-626
1-benzyl-3-methyl imidazolium hydrogen sulphate [bnmim][HSO4] was found to be an effective catalyst for the condensation reaction of indoles and derivatives with benzaldehydes in microwave
irradiation with lower reaction time and higher yields to give bis(indolyl) methanes.
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8.
A one-pot multi-component reaction is developed for the efficient synthesis of 4,5-dibenzylidene octahydroacridines in high
yields. The reaction is performed by the tandem reaction of three molar equivalent aromatic aldehydes with two molar equivalent
4-alkylcyclohexanone in the system of NH4OAc/HOAc under microwave irradiation.
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9.
Huitao Liu Yingying Wen Feng Luan Yuan Gao Yun Guo Zhaoyang Xie Zhide Hu 《Central European Journal of Chemistry》2009,7(1):59-65
Models to predict binding constant (logK) to bovine serum albumin (BSA) should be very useful in the pharmaceutical industry to help speed up the design of new compounds,
especially as far as pharmacokinetics is concerned. We present here an extensive list of logK binding constants for thirty-five compounds to BSA determined by florescence quenching from the literature. These data have
allowed us the derivation of a quantitative structure-property relationship (QSPR) model to predict binding constants to BSA
of compounds on the basis of their structure. A stepwise multiple linear regression (MLR) was performed to build the model.
The statistical parameter provided by the MLR model (R = 0.9200, RMS = 0.3305) indicated satisfactory stability and predictive
ability for the model. Using florescence quenching spectroscopy, we also experimentally determined the binding constants to
BSA for two bioactive components in traditional Chinese medicines. Using the proposed model it was possible to predict the
binding constants for each, which were in good agreement with the experimental results. This QSPR approach can contribute
to a better understanding of structural factors of the compounds responsible for drug-protein interactions, and be useful
in predicting the binding constants of other compounds.
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10.
Robert Musiol Josef Jampilek Barbara Podeszwa Jacek Finster Dominik Tabak Jiri Dohnal Jaroslaw Polanski 《Central European Journal of Chemistry》2009,7(3):586-597
In the present paper we describe results on the synthesis and lipophilicity determination of a series of biologically active
compounds based on their heterocyclic structure. For synthesis of styrylquinoline-based compounds we applied microwave irradiation
and solid phase techniques. The correlation between RP-HPLC retention parameter log k (the logarithm of retention factor k) and log P data calculated in various ways is discussed, as well as, the relationships between the lipophilicity and the chemical structure
of the studied compounds.
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11.
Rayna Bryaskova Nelly Georgieva Dimitar Peshev 《Central European Journal of Chemistry》2010,8(5):1053-1058
Polyvinyl alcohol (PVA) and tetraethoxysilane (TEOS) hybrid materials were prepared by sol-gel methods and tested as matrices
for immobilization of Trichosporon cutaneum R57, capable of removing cadmium and copper ions from aqueous solutions. A kinetic model was applied and the effects of matrix
TEOS content on the copper and cadmium uptake equilibria and rate constants were investigated.
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12.
The relative enthalpies of melts in the system KF - K2NbF7 were measured by drop-calorimetry at the temperatures 1058, 1140 and 1208 K as a function of composition. Heat capacities
of melted mixtures and enthalpies of mixing were determined using the experimental data. The molar heat capacity of melts
diverges slightly from additivity. The molar enthalpy of mixing of melts shows small negative deviation from ideality which
decreases with decreasing temperature. The thermal effect at mixing was assigned predominantly to association reactions producing
more complex fluoroniobate anions.
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Nadezhda Rangelova Lachezar Radev Sanchi Nenkova Isabel M. Miranda Salvado Maria H. Vas Fernandes Michael Herzog 《Central European Journal of Chemistry》2011,9(1):112-118
Methylcellulose (MC) / SiO2 organic / inorganic hybrid materials have been prepared from MC and methyltriethoxysilane or ethyltrimethoxysilane, and characterized
by XRD, FTIR and AFM. XRD showed peak shifts. FTIR shows intermolecular hydrogen bonding between MC and SiO2. AFM depicts surface roughness which depends on the silica precursor and MC content.
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15.
Huitao Liu Yingying Wen Feng Luan Yuan Gao Xiuyong Li 《Central European Journal of Chemistry》2009,7(3):439-445
The half-wave potential (E1/2) is an important electrochemical property of organic compounds. In this work, a quantitative structure-property relationship
(QSPR) analysis has been conducted on the half-wave reduction potential (E1/2) of 40 substituted benzoxazines by means of both a heuristic method (HM) and a non-linear radial basis function neural network
(RBFNN) modeling method. The statistical parameters provided by the HM model (R2 =0.946; F=152.576; RMSCV=0.0141) and the RBFNN model (R2=0.982; F=1034.171 and RMS =0.0209) indicated satisfactory stability and predictive ability. The obtained models showed that
benzoxazines with larger Min valency of a S atom (MVSA), lower Relative number of H atom (RNHA) and Min n-n repulsion for
a C-H bond (MnnRCHB) and Minimal Electrophilic Reactivity Index for a C atom (MERICA) can be more easily reduced. This QSPR
approach can contribute to a better understanding of structural factors of the organic compounds that contribute to the E1/2, and can be useful in predicting the E1/2 of other compounds.
相似文献
16.
A series of novel cyclic urea molecules 5,6-dihydroxy-1,3-diazepane-2,4,7-trione as HIV-1 protease inhibitors were designed
using computational techniques. The designed molecules were compared with the known cyclic urea molecules by performing docking
studies, calculating their ADME (Absorption, Distribution, Metabolism, and Excretion) properties and protein ligand interaction
energy. These novel molecules were designed by substituting the P
1/P′
1 positions (4
th
and 7
th
position of 1, 3-diazepan-2-one) with double bonded oxygens. This reduces the molecular weight and increases the bioavailability,
indicating better ADME properties. The docking studies showed good binding affinity towards HIV-1 protease. The biological
activity of these inhibitors were predicted by a model equation generated by the regression analysis between biological activity
(log 1/K
i
) of known inhibitors and their protein ligand interaction energy. The synthetic studies are in progress.
相似文献
17.
B.B. Koleva T. Kolev R. Nikolova Y. Zagraniarsky M. Spiteller 《Central European Journal of Chemistry》2008,6(4):592-599
Novel dicyanoisophorone derivative, (E)-2-(3-(4-aminostyryl)-5,5-dimethylcyclohex-2-enylidene)malononitrile, is synthesized and its structure elucidated by means
of conventional and linear polarized IR-spectroscopy of oriented colloids in nematic host, 1H, 13C, 1H, 1H-COSY NMR, HPLC tandem ESI MS-MS spectrometry, UV-VIS and thermal methods. Ab initio and DFT level of theory are used to theoretically obtain the electronic structure and optical properties, both in ground
and exited state, of the compound.
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Mónica Díaz-Pérez Manuel Aboal-Somoza Pilar Bermejo-Barrera Adela Bermejo-Barrera 《Central European Journal of Chemistry》2008,6(4):520-525
Preliminary results of development of a direct and fast method of determination of antimony in samples of tap water using
GFAAS are presented. The found levels of antimony were lower than permitted for human consumption. A mixture of Pd and Mg(NO3)2 (concentrations in the injected solution: 8.6 μg mL−1 and 5.8 μg mL−1 respectively) was used as the chemical modifier. The pyrolysis and atomization temperatures were 1000 and 1700°C, respectively
and the mean analytical recovery 98.2%.
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