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Abstract

The lipophilicity of thirty-two novel acetylcholinesterase (AChE) inhibitors — 1,2,3,4-tetrahydroacridine and 2,3-dihydro-1H-cyclopenta[b]quinoline derivatives was studied by thin layer chromatography. The analyzed compounds were chromatographed on RP-18, RP-8, RP-2, CN and NH2 stationary phases with dioxane — citric buffer pH 3.0 binary mobile phases containing different proportions of dioxane. RM values for pure water were extrapolated from the linear Soczewiński-Wachtmeister equation and six compounds with known literature log P values were used as reference calibration data set for computation of experimental log P values. The obtained results were compared with computationally calculated partition coefficients values (AlogPs, AClogP, AlogP, MlogP, KOWWIN, XlogP2, XlogP3) by PCA and significant differences between them were observed.

melt. Apatites were equilibrated experimentally with carbonatite melts at 1 GPa and 1250 ∞C, and run products were analyzed for trace elements by secondary ion mass spectrometry (SIMS) and by laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS). Calculated partition coefficients indicate incompatibility of most analyzed elements. Rare-earth element (REE) parti- tion coefficients show a convex-upward pattern, indicating that apatite prefers the middle (Sm, Gd) relative to the lighter (La, Ce, Pr) and heavier REE (Lu). Comparison of partition

. The calculated values for DAuUsp/melt and DCuUsp/melt indicate that the addition of Ti to magnetite increases significantly the Au- and Cu-scavenging potential of ulvöspinel relative to end-member magnetite. Partition coefficients for Cu and Au between pyr- rhotite and melt indicate that a temperature change from 1050 to 800 °C in an anhydrous and hydrous assemblage, respectively, results in no observable change in Cu partitioning. The calculated partition coefficients are used to model the effect of crystal fractionation on the concentrations of Ag, Cu, and Au

agreement with the presence of a significant phengitic component. Reduction in biotite unit-cell dimensions with the increase of Al follows a pattern similar to that of associated muscovites, and the octahedral site volumes of both micas are influenced by the Al saturation index (ASI) of the rock. These results, and the calculated partition coefficients between biotite and muscovite for elements in M sites, are consistent with continuous reaction and re-equilibration of biotite and muscovite during crystallization of peraluminous granitic melts. tent, which accounts for

Abstract

The aim of the present study was to determine the anticonvulsant effects of xanthotoxin (8-methoxypsoralen) isolated from the fruit of Pastinaca sativa L. This plant is used in European traditional medicine, including Poland. For this purpose, high-performance counter-current chromatography was used. Different solvent systems, mixtures of n-heptane, ethyl acetate, methanol and water were tested in order to calculate partition coefficients. Finally, a mixture with the ratio of 1:1:1:1 (v/v/v/v), giving the K value = 0.92, was chosen as optimal. A rapid scale-up process from analytical to preparative was developed. Evaluation of the anticonvulsant action of xanthotoxin in the mouse maximal electroshock-induced seizure test revealed that it produced a clear-cut anticonvulsant action in mice, and the experimentally-derived median effective doses (ED50 values) ranged between 219 and 252 mg kg−1.

Abstract

The activity of fungicide agents containing a quinazolinone ring was described using the quantitative structure-activity relationship (QSAR) model by applying it to data taken from literature. The title compounds exhibit two important types of activity against certain fungal pathogens, i.e. activity against yeast and activity against filamentous fungi. A correlation between both antifungal activities (e.g. FA(yst) and FA(ff)) and physicochemical parameters such as the logarithm of the n-octanol/water partition coefficient (log P), the polarizability (P), the global minimum energy (TE), the energy difference between the frontier molecular orbital (DELH) and the molar refractivity (MR), was established using multiple linear regression. The molecular descriptors of the antifungal agents were obtained by quantum chemical calculations combined with molecular modeling calculations. Statistical analysis shows that the antifungal activity depends mainly on the calculated partition coefficients, log P, of the compounds. Bi-parametric models reveal that antifungal activity relates linearly to log P and P.

Abstract

Starting from N-hydroxyphthalimide 1 and the reactive fluoro- or chloro-nitroaryl derivatives 2, 3 and 4a-e (2-chloro-3,5-dinitropyridine; 3, NBD-chloride; 4a, 1-fluoro-2,4-dinitrobenzene; 4b, picryl chloride; 4c, 4-chloro-3,5-dinitrobenzotrifluoride; 4d, 2-chloro-3,5- dinitrobenzotrifluoride; 4e, 4-chloro-3,5-dinitrobenzoic acid) the corresponding N-(2-nitroaryloxy)-phthalimide derivatives 5a-e, or 6 and 7 were obtained and characterized by IR, UV-Vis 1H-NMR and 13C-NMR spectroscopy. The TLC behavior and the hydrophobicity of these derivatives have been experimentally evaluated by RM0 parameters (using RP-TLC). The experimental RM0 parameters were compared with the calculated partition coefficient, log P. A QSPR study was also performed to establish possible correlations between the structure and physical properties (λmax and RM0) of compounds 5a-e, 6, and 7.

denotes the partition coefficient for i2+. In the simula- tions DMg is 1.43 (by definition), hence Equation 3 can be used to calculate Di from ∆Hex for each of the simulated species (Table 2). EXPERIMENT To test our calculated partition coefficients we have per- formed experiments under conditions identical to those in the simulations. Experimental starting materials were sintered pow- ders of MgO and SiO2, with approximate bulk composition 60 wt% SiO2 (Table 2), doped at the ppm level with a suite of trace elements using nitrate solutions (Ni, Mn, Co, Zn, Cu, Cd) or

, oriented in palisade layer [ 3 ], [ 9 ], [ 20 ], [ 21 ], [ 22 ], [ 23 ], [ 24 ], [ 25 ]. Figure 3b and c display the plots to calculate partition coefficient and binding constants, respectively. Fig. 3: (a) Plot of differential absorbance of RB-5 as a function of CTAB concentration. (b) Relationship between (∆ A ) −1 and ( C d + C s m o ) − 1 ${({C_d} + C_s^{mo})^{ - 1}}$ for calculation of K x for the RB-5/CTAB system. (c) Relationship between C s and C s C a /∆ A for calculation of K b for the RB-5/CTAB system. Tables 1 and 2 display data for

standards, ratios observed to published data overlap within er- ror for all elements except Sr, Y, and La (for a discussion of these exceptions see legend of Fig. 2). The absence of differen- tial matrix effects for glass relative to garnet means the accu- racy of our calculated partition coefficients is better than the percentages given above. RESULTS AND DISCUSSION Experimental products and their compositions are listed in Tables 2 and 4, respectively. All experiments produced several homogeneous garnets with a maximum diameter of about 30 µm. Experiments 8 and 11