In recent years there has been considerable interest in the synthesis and separation of enantiomers of organic compounds especially because of their importance in the biochemistry and pharmaceutical industry. High-performance liquid Chromatography is a very useful method for the direct separation of enantiomers. However, about 30−40 years ago, commercially available chiral stationary phases were very limited. Researchers developed many novel chiral stationary phases for gas and liquid chromatography, and found these phases were effective practically to the separation and analysis of various chiral compounds. Enantioseparation of drugs with multiple chiral centers is challenging. This review describes resolution of some drugs with multiple chiral centers using polysaccharide-type chiral stationary phases. پرونده مقاله

The β-carboline derivatives are a large group of naturally-occurring and synthetic alkaloids which have awide spectrum of biological and pharmaceutical properties. The newly developed procedure called VolSurfhas been used to explore a significant correlation between the 3D molecular interaction fields (MIF) andphysicochemical and pharmacokinetic properties of a set of 30 β-carboline compounds acting as antitumoragents. In general terms, VolSurf generates a limited set of quantitative numerical descriptors from MIFs bycalculating the volume or the surface of the interaction contours. These descriptors that encode theinformation content from the chosen probes are simple to interpret from a chemistry point of view. The aimof this approach is to allow the analysis of a large number of quantitative descriptors by using chemometrictools such as partial least squares (PLS) and principle component analysis (PCA). The PLS model gavestatistically significant results with R2 and Q2 values of 0.92 and 0.72, respectively. The ability of the modelwas validated by an external test set of 10 compounds, which gave R2(pred) of 0.85. The VolSurf modeldeveloped here identifies hydrophobicity as the major physicochemical parameters responsible for theantitumor activity of the β-carboline derivatives towards HepG2 cell lines. پرونده مقاله

A conductance study of the interaction between Cs+, Rb+, NH4+, K+, T1+ and Ag+ ions and18-crown-6 (18C6), benzo-18-crown-6 (B18C6), dicyclohexyl-18-crown-6 (DC18C6),dicyclohexyl-24-crown-8 (DC24C8), dibenzo-24-crown-8 (DB24C8) in different binarymixtures of acetonitrile (AN) with dimethylsulfoxide (DMSO) and dimethylformamide (DMF)at 25 °C has been carried out. Formation constants of the resulting 1:1 complexes weredetermined from the conductance-mole ratio data and found frequently vary in the orderDC18C6 > 18C6 > B18C6 > DC24C8 > DB24C8 for Rb+ ion and DC18C6 > DC24C8 > 18C6> B18C6 > DB24C8 for NH4+ ion, DC24C8 > DC18C6 > 18C6 > B18C6 ≈ DB24C8 for Cs+ion, DC18C6> DC24C8 > 18C6 > B18C6 > DB24C8 for K+ ion, DC24C8 > DC18C6 > 18C6 > B18C6 >DB24C8 for Tl+ ion and DC24C8 > DC18C6 > 18C6 > DB24C8 > B18C6 for Ag+ ion. It wasfound that the stability of the resulting complexes increased by increasing acetonitrile molefraction in the solvent mixtures. The interactions of the solvent molecules with metal ions andligands show an important role for the complex formation process. Therefore, in addition toinfluences of the solvent, the effects of the number of members in the macrocycle, nature of thesubstituents in the polyether ring and cavity size are discussed. پرونده مقاله

A partial least squares (PLS) calibration model was developed for the simultaneous spectrophotometricdetermination of Pb (ΙΙ), Cu (ΙΙ) and Ni (ΙΙ) using xylenol orange as a chromogenic reagent. The parameterscontrolling behavior of the system were investigated and optimum conditions were selected. The calibrationgraphs were linear in the ranges of 0.0–9.091, 0.0–2.719 and 0.0–2.381 ppm for lead, copper and nickel,respectively. The experimental calibration matrix was designed with 21 mixtures of these chemicals.Absorbance data were taken between 350-650 nm and absorbance data were autoscaled. A set of syntheticsample mixtures were used to validate the proposed method. The root mean square errors of predictions(RMSEPs) and percent of relative prediction errors (RSEPs) are 0.2164, 0.0744, 0.0735 ppm and ±7.1855, ±6.3193, ± 7.0806% for lead, copper and nickel, respectively. پرونده مقاله

A series of 42 Pyrazolo[4,3-h]quinazoline-3-carboxamides as multi-cyclin-dependent kinaseinhibitors regarded as promising antitumor agents to complement the existing therapies, wassubjected to a three-dimensional quantitative activity relationship (3D QSAR). Different QSARmethods, comparative molecular field analysis (CoMFA), CoMFA region focusing, andcomparative molecular similarity indices analysis (CoMSIA), were compared. All these QSARbasedmodels had good statistical parameters and yielded q2 values of 0.717, 0.806, and 0.557,respectively. The CoMFA region focusing model provided the highest q2 and r2 values, whichimplied the significance of correlation of steric and electrostatic fields with biological activities.The quality of CoMSIA was slightly lower than that of CoMFA region focusing in terms of q2and r2 values. The results of 3D contour maps can be useful for the future development of CDKsinhibitors. The results of 3D QSAR models are in agreement with docking results, and thestatistical parameters of the models explain that the data are well fitted and have high predictiveability. پرونده مقاله