A strategy for the build-up of transition-metal complexes containing tripodal [ArPOS2]2- and [ArPS3]2- ligands (Ar = 4-anisyl)

The investigation presents new synthetic methods for the generation of tripodal P/S ligands by reactions of metal alkoxides and carboxylates with the organoperthiophosphinic acid anhydride Lawesson's reagent. Four new transition-metal complexes containing various tripodal ligand sets were synthesised and characterised.     

A comparative study of first-derivative spectrophotometry and high-performance liquid chromatography applied to the determination of losartan potassium in tablets

Losartan, a highly effective blood pressure-lowering agent, has been widely used for the treatment of hypertension. A fast and reliable method for the determination of losartan was highly desirable to support formulation screening and quality control. A first-derivative UV spectroscopic method and HPLC were developed for the determination of losartan in the tablet dosage form. The first-derivative spectrum recorded between 220 and 320 nm and a zero-crossing technique for first-derivative measurement at 232.5 nm were selected. The selectivity and sensitivity of the method was in desirable range. In comparison with the direct UV method, first-derivative UV spectroscopy has a definite trough without any interference from UV absorbing-excipients. This method is also fast and economical in comparison with the more time-consuming HPLC method regularly used for formulation screening and quality control and can be used routinely by any laboratory possessing a spectrophotometer with a derivative accessory. The linear concentration ranges were 2-50 microg ml(-1), (D(1)=-0.0159C-0.0056, r=0.9994, n=6). Between-days CV of < or =2.9%, within-day CV of < or =2.1%, and analytical recovery close to 98.1% show the suitability of the method for determination in quality control.     

Oxidation of Aromatic Amines to Quinones by Iodic Acid under Microwave Irradiation in the Presence of Montmorillonite K10 and Silica Gel

Summary. A variety of aromatic amines are oxidized to their corresponding quinones in excellent yields by supported iodic acid under microwave irradiation and solvent free conditions.     

Hermite-based Appell polynomials: Properties and applications

By employing certain operational methods, the authors introduce Hermite-based Appell polynomials. Some properties of Hermite-Appell polynomials are considered, which proved to be useful for the derivation of identities involving these polynomials. The possibility of extending this technique to introduce Hermite-based Sheffer polynomials (for example, Hermite-Laguerre and Hermite-Sister Celine's polynomials) is also investigated.     

Surprising Formation of Chlorinated Butenolides from Dialkyl Acetylenedicarboxylates and Hexachloro­acetone in the Presence of Triphenyl Phosphite

Triphenyl phosphite reacts smoothly with dialkyl acetylenedicarboxylates and hexachloroacetone to produce alkyl 2‐(dichloromethylene)‐2,5‐dihydro‐5‐oxo‐4‐(trichloromethyl)furan‐3‐carboxylates in good yields.     

CuI-catalyzed Coupling Reactions of Aryl Iodides with Amides Using L-Proline and KF/Al2O3

An efficient experimentally simple and inexpensive catalyst system for the selective amidation of aryl iodides using 15 mol% of CuI as catalyst, 15 mol% of L-proline as ligand and KF/Al2O3 as a base in toluene is described.     

Kinetic modeling of aqueous phenol degradation by UV/H2O2 process

A dynamic kinetic model for the oxidation of phenol in water by an UV/H₂O₂ process is developed. The model is based on the elementary chemical and photochemical reactions, initiated by the photolysis of hydrogen peroxide into hydroxyl radicals. The model is validated by using experimental data obtained from the open literature for an actual UV/H₂O₂ process. Using those data and the developed kinetic model, kinetic rate constants for phenol intermediates, catechol and hydroquinone, are estimated. Moreover, the optimum initial hydrogen peroxide concentration is estimated by means of the validated model. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 40: 34–43, 2008     

Septic spline solutions of sixth-order boundary value problems

Septic spline is used for the numerical solution of the sixth-order linear, special case boundary value problem. End conditions for the definition of septic spline are derived, consistent with the sixth-order boundary value problem. The algorithm developed approximates the solution and their higher-order derivatives. The method has also been proved to be second-order convergent. Three examples are considered for the numerical illustrations of the method developed. The method developed in this paper is also compared with that developed in [M. El-Gamel, J.R. Cannon, J. Latour, A.I. Zayed, Sinc-Galerkin method for solving linear sixth order boundary-value problems, Mathematics of Computation 73, 247 (2003) 1325–1343], as well and is observed to be better.     

Ellagic acid and human cancers: a systems pharmacology and docking study to identify principal hub genes and main mechanisms of action

Research on anticancer properties of natural compounds, as effective materials that are available while causing minimal side effects, is growing. Ellagic acid (EA) is a well-known polyphenolic compound, which has been found in both free and complex modes in several medicinal plants such as pomegranate, walnut, and berries. Although many articles have reported anticancer properties for this compound, its mechanism of action has not been fully elucidated. In this study, we used several online and offline bioinformatics tools and databases to identify the mechanism of action of EA on various types of human malignancies including bladder, blood, breast, cervical, colorectal, liver, pancreas, and prostate cancers. In this context, after identifying and extracting EA-affected human genes/proteins that have been reported in various references, we built the related gene networks and determined functional hub genes. In addition, docking was performed to recognize target proteins that react directly with EA and are in fact most affected by this compound. Our findings revealed that EA exerts its anticancer effects by influencing specific hub genes in various types of cancers. Moreover, different cellular signaling pathways are affected by this natural compound. Generally, it turned out that EA probably exerts most of its anticancer activities, through induction of apoptosis, as well as P53 and WNT signaling pathways, and also by affecting the expression of several hub genes such as CDKN1A, CDK4, CDK2, CDK6, TP53, JUN, CCNA2, MAPK14, CDK1, and CCNB1 and especially interactions with some related proteins including P53, CDK6, and MAPK14.