N-Bromo Reagent Mediated Oxidation of Urazoles to Their Corresponding Triazolinediones under Mild and Heterogeneous Conditions

Various N-bromo reagents [HMTAB, DABCO-bromine, DPTBE, and TBCA] were used as effective oxidizing agents for the oxidation of urazoles and bisurazoles to their corresponding triazolinediones under mild and heterogeneous conditions at room temperature with good to excellent yields. Also the oxidation of some new 4-phenylurazole derivatives with these reagents is discussed.     

Bis‐aroylhydrazone based on 2,2′‐bis substituted diphenylamine for synthesis of new binuclear organotin (IV) complexes: Spectroscopic characterization,crystal structures,in vitro DNA‐binding,plasmid DNA cleavage,PCR and cytotoxicity against MCF7 cell line

New dinuclear organotin (IV) complexes, Me₄Sn₂L, Ph₄Sn₂L and Bu₄Sn₂L, have been synthesized from reaction of R₂SnCl₂ (R = Me, Ph and Bu) with a 2,2′‐bis‐substituted diphenylamine arοylidene hydrazone, H₄L. The synthesized compounds were investigated by elemental analysis and infrared, ¹H‐NMR and ¹¹⁹Sn‐NMR spectroscopy. The structures of H₄L, Me₄Sn₂L and Bu₄Sn₂L were also confirmed by X‐ray crystallography. H₄L molecules adopt (E)‐configuration and keto‐tautomeric form in the solid state. In all complexes, the bis‐hydrazone acts as a tetra‐anionic ligand with two contiguous ONO tridentate domains that coordinate the two R₂Sn moieties in the enolate form. The coordination environments of both tin centers are five‐coordinate. DNA‐binding studies were performed by UV–Vis spectroscopy, and the results indicate that the synthesized compounds significantly interact with calf thymus‐DNA in the intercalative mode. The results of polymerase chain reaction assay show that all the compounds affect on amplification of DNA, and complexes are more effective than ligands. The in vitro cytotoxicity against the human breast cancer line (MCF7) was determined using the MTT assay, and H₄L and the dibutytin complex showed higher activity.     

Type II c-Met inhibitors: molecular insight into crucial interactions for effective inhibition

The c-Met tyrosine kinase plays an important role in human cancers. Preclinical studies demonstrated that c-Met is over-expressed, mutated and amplified in a variety of human tumor types and design of more potent c-Met inhibitors is a priority. In this study, 14 molecular dynamics simulations of potent type II c-Met inhibitors were run to resolve the critical interactions responsible for high affinity of ligands towards c-Met considering the essential flexibility of protein–ligand interactions. Residues Phe1223 and Tyr1159, involved in pi-pi interactions were recognized as the most effective residues in the ligand binding in terms of binding free energies. Hydrogen bond interaction with Met1160 was also found necessary for effective type II ligand binding to c-Met.

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Polymeric ionic liquid material‐anchored Mn–porphyrin anion: Heterogeneous catalyst for aerobic oxidation of olefins

P(APTMACl)‐[Mn(TPPS)(OAc)] heterogeneous catalyst system comprised of anionic [Mn(tetrakis(4‐sulfonatophenyl)porphyrin)(OAc)] ([Mn(TPPS)(OAc)]) embedded within cationic cross‐linked polymeric ionic liquid (poly[(3‐acrylamidopropyl)trimethylammonium chloride], p(APTMACl)) hydrogel matrices was used for the selective aerobic oxidation of olefins. P(APTMACl)‐[Mn(TPPS)(OAc)] hydrogel was synthesized by radical polymerization in a solution of cationic APTMACl as an ionic liquid monomer, N,N′‐methylenebisacrylamide as cross‐linking agent, ammonium persulfate as initiator and N,N,N′,N′‐tetramethylmethylenediamine as accelerator in the presence of anionic [Mn(TPPS)(OAc)]. P(APTMACl)‐[Mn(TPPS)(OAc)] was characterized using Fourier transform infrared, diffuse reflectance UV–visible and atomic absorption spectroscopies and scanning electron microscopy. Differential scanning calorimetry was used for measuring the glass transition temperature. Catalytic activity of p(APTMACl)‐[Mn(TPPS)(OAc)] was investigated in the aerobic oxidation of olefins with emphasis on the effect of various parameters such as temperature, catalyst amount, substituent effect, etc. The catalyst was easily recovered from the reaction medium and could be re‐used for another seven runs without significant loss of activity.     

Secondary amines immobilized inside magnetic mesoporous materials as a recyclable basic and oxidative heterogeneous nanocatalyst for the synthesis of trisubstituted pyrimidine derivatives

Research on Chemical Intermediates - A novel magnetic MCM-41 nanocomposite-based catalyst is reported for the first time in the multicomponent synthesis of trisubstituted pyrimidines in which...     

Solvent Effects on Protonation Constants of Imatinib in Different Aqueous Solutions of Methanol at T = 298.15 K

Russian Journal of Physical Chemistry A - Imatinib (Gleevec) is a drug that is applied to treat cancer. It inhibits the Bcr-Abl tyrosine-kinase and therefore, it can slow growth or result in...     

A Facile and One‐pot Synthetic Route to Functionalized Ethyl 3‐(Alkanoyl)‐2‐(alkyl imino)‐2,3‐dihydrothiazole‐4‐carboxylate Derivatives under Mild,Solventand Catalyst‐free Conditions

A new one‐pot, four‐component synthetic rout is reported for the preparation of functionalized N‐acyl‐2alkylimino‐2,3‐dihydrothiazole derivatives from the reaction between acid chlorides, ammonium thiocyanate, primary alkylamines, and ethyl bromopyruvate under mild, solvent‐ and catalyst‐free conditions at room temperature. This completely green and efficient straight forward procedure led to the desired products in good to high yields without any need to catalyst or solvent assistance and no by product was observed in all the reactions     

Highly selective iodide membrane electrode based on a cerium salen.

A highly selective PVC membrane electrode based on a cerium-salen complex was prepared. The sensor displays an anti-Hofmeister selectivity sequence with a preference for iodide ion over many common organic and inorganic anions. The proposed electrode exhibits a near-Nernstian behavior over a wide concentration range (5.0 x 10(-2) - 8.0 x 10(-6) M) with a slope of 57.5 mV per decade, and a detection limit of 6.0 x 10(-6) M. The electrode has a very fast response time and can be used in the pH range of 3.0 - 1 1.0. It was applied, as an indicator electrode, in potentiometric titration of Ag+ ions.     

Determination of SCN- in urine and saliva of smokers and non-smokers by SCN(-)-selective polymeric membrane containing a nickel(II)-azamacrocycle complex coated on a graphite electrode.

The construction, performance characteristics, and application of a novel polymeric membrane coated on a graphite electrode with unique selectivity towards SCN- are reported. The electrode was prepared by incorporating Ni(II)-2,2,4,9,9,11-hexamethyltetraazacyclotetradecanediene perchlorate into a plasticized poly(vinyl chloride) membrane. The influences of membrane composition, pH and foreign ions were investigated. The electrode displays a near Nernstian slope (-57.8 mV decade-1) over a wide concentration range of 1 x 10(-7)-1 x 10(-1) M of SCN- ion. The electrode has a detection limit of 4.8 x 10(-8) M (2.8 ng/cm3) SCN- and shows response times of about 15 s and 120 s for low to high and high to low concentration sequences, respectively. The proposed sensor shows high selectivity towards SCN- over several common organic and inorganic anions. The electrode revealed a great enhancement in selectivity coefficients and detection limit for SCN-, in comparison with the previously reported electrodes. It was successfully applied to the direct determination of SCN- in milk and biological samples, and as an indicator electrode in titration of Ag+ ions with thiocyanate.