Synthesis and biological evaluation of 3-hydroxypyrazoles as aquaporin 9 inhibitors

A series of 3-hydroxypyrazole derivatives have been synthesized by a base-promoted reaction of nitro-substituted donor–acceptor cyclopropanes with hydrazines. The synthesized compounds have been investigated for their ability to inhibit aquaporin 9 (AQP9) in rat Leydig cells (LC-540). The protein data bank structure for AQP9 was predicted using homology modeling; and the protein–ligand interaction for the synthesized hydroxyl pyrazole derivatives were analyzed using molecular modeling and docking studies. The results of in silico analyses showed that compound 5b had a higher binding affinity with AQP9 than other compounds. Further, in vitro studies conducted in LC-540 cells confirmed that compound 5b effectively inhibits AQP9. Hence, compound 5b may be used as an inhibitor in enhancing our understanding of AQP9 function, and in the treatment of several diseases.     

Influence of a dopant source on the structural and optical properties of Mn doped ZnGa<Subscript>2</Subscript>O<Subscript>4</Subscript> thin films

Thin films of ZnGa₂O₄:Mn²⁺ were deposited on quartz substrates using an rf magnetron sputtering technique. The sputtering target, ZnGa₂O₄ doped with 2 at. % manganese, was synthesized by a high temperature solid state reaction. Two different dopant sources were used to incorporate the dopant ions into the target, namely, manganese acetate and manganese oxide. The structural and optical properties of the thin films were studied using XRD, PL and transmission spectra. Polycrystalline ZnGa₂O₄:Mn with a spinel structure could be grown at an optimized substrate–target distance even at room temperature. No luminescence was observed in the as-deposited films grown using (CH₃COO)₂Mn as the dopant source in the target. Substrate heating or post-deposition annealing in the reducing ambient didn’t impart any luminescence to the films, ruling out the possibility of Mn²⁺ incorporation in the films. However, when using MnO as the manganese source in the target, the as-deposited films exhibited green photoluminescent emission (peak maximum at 508 nm) for substrate temperatures at and above 500 °C. This suggests that, in thin films, Mn incorporation and subsequent luminescent outcome is strongly influenced by the dopant source, which is quite different from the bulk phosphor behavior. PACS 81.15.Cd; 78.55.-m; 85.60.-q     

Dendrimers as photochemical reaction media. Photochemical behavior of unimolecular and bimolecular reactions in water-soluble dendrimers

Synthesis and studies of poly(alkyl aryl ether) dendrimers, possessing carboxylic acid functionalities at their peripheries, are reported. 5-Bromopentyloxy methylisophthalate was utilized as the monomer to O-alkylate the phenolic hydroxyl groups of poly(alkyl aryl ether) dendrimers. Dendrimers of first, second, and third generations, possessing 6, 12, and 24 carboxylic acids, respectively, were thus prepared. These dendrimers were soluble in alkaline aqueous solutions, and the ensuing microenvironmental properties of the aqueous solutions were assessed by pyrene solubilization studies. Upon establishing the presence of nonpolar microenvironments within the dendritic structures, solubilizations of few organic substrates were conducted and their photochemical behaviors were assessed. Specifically, the photolysis of 1-phenyl-3-p-tolyl-propan-2-one and benzoin ethyl ether and photodimerization of acenaphthylene were conducted. These studies revealed that the product distribution and the "cage effect" were more distinct and efficient for the third generation dendrimer, than for the first and second generation dendrimers. The photochemical studies of carboxylic acid functionalized dendrimers were compared to that of hydroxyl group terminated poly(alkyl aryl ether) dendrimers.     

SERS studies on 1–4 dihydroxyanthraquinone at Ag electrode

Raman scattering studies on 1–4 dihydroxyanthraquinone (DHAQ) at Ag electrode have been carried out to investigate the enhancement in the spectral line intensity after adsorption. Charge transfer between the adsorbate and the substrate is more pronounced for certain normal modes of vibration. It is found that the DHAQ molecules are lying with their molecular plane on the top of the metal surface. Laser induced fluorescence spectra of DHAQ have also been analysed with a view to assign the relative orientation of absorption and emission dipoles.     

Anion-molecular interaction through CH3 groups: Model ab initio studies

3-21G, 6–31G and 6–31 +G calculations have been performed on Cr…H₃CCl and LiCl…H₃CCl complexes with two different configurations each. Optimized geometries, stabilization energies, CH force constants and harmonic vibrational frequencies for CH₃Cl and its complexes are reported. Comparison of the calculated frequency shifts of CH-stretching bands of CH₃C1, on complexation, with experimental results of related systems indicate that the interaction of Cl^- with CH₃ group takes place in a linear manner with the CH bond. A lower frequency shift for LiCl…H₃CX with reference to the C1^-…H₃CX complexes is explained on the basis of the reduction of the basicity of Cl^- ion in the presence of counter ion in the former complex considered.     

An EPR and NMR study of supramolecular effects on paramagnetic interaction between a nitroxide incarcerated within a nanocapsule with a nitroxide in bulk aqueous media

A 15N-labeled nitroxide was incarcerated into an octa acid nanocapsule, which was confirmed by 1H NMR and EPR spectroscopy. Electron paramagnetic interaction between the 15N-labeled incarcerated nitroxide and a 14N-labeled free nitroxide in the external aqueous solution was observed by EPR spectroscopy. The observation of spin-spin interaction, through the walls of the cancer and is reflected in the simultaneous line-broadening of both the 15N-labeled and 14N-labeled nitroxides. The computer-assisted analysis of the EPR data further provides direct information on the motion and the polarity of both the incarcerated paramagnetic nitroxide and the nitroxides in the external bulk aqueous phase. We also show how communication between an incarcerated guest and molecules in the bulk solvent can be enhanced or inhibited by supramolecular factors such as Coulombic attraction or repulsion between a charged guest@host complex (incarcerated 15N nitroxide) and charged molecules in the aqueous phase.