The Synthesis of Hetero-Halogenated Derivatives of Phloroglucide Analogues[1]

A short synthesis of the title compounds is reported. Most of the compounds prepared were found to be active against a number of pathogenic microorganisms in vitro.     

Reaction of trifluoromethanesulfonyl chloride with dialkyl hydroxyalkylmalonates. A synthesis of 2,2,-disubstituted tetrahydrofurans,pyrans and pyrrolidines

Diethyl 2-(ω-hydroxypropyl or butyl) malonates are shown to give 2,20dicarbethoxytetrahydrofuran or tetrahydropyran, when allowed to react with CF₃SO₂Cl/NEt₃ in CH₂Cl₂.     

Green and one-pot synthesis of novel amidoalkyl naphthols using triethanolammonium acetate [(OHCH2CH2)3NH][OAc]) ionic liquid and their anti-H.pylori activity

Research on Chemical Intermediates - Nearly half of the world's population have been infected with Helicobacter pylori (H. pylori) which is known as the main cause of chronic gastritis,...     

Tandem magnetization and post‐synthetic metal ion exchange of metal–organic framework: Synthesis,characterization and catalytic study

For the first time, metal‐exchange in a magnetic metal–organic framework (MOF) via tandem magnetization and post‐synthetic modification has been developed. The new magnetic mixed‐metal metal–organic framework nanocomposite, CoFe₂O₄/[Cu_0.63/Zn_0.37‐TMU‐17‐NH₂] (CoFe₂O₄/[Cu/Zn‐MOF]) has been synthesized by immersing the CoFe₂O₄/Zn‐TMU‐17‐NH₂ (CoFe₂O₄/Zn‐MOF) as a template in DMF solution of Cu (II) salts. CoFe₂O₄/[Cu/Zn‐MOF] showed to be a highly reactive and easily recoverable magnetic catalyst for the preparation of tetrazole derivatives via one‐pot three‐component reactions of different aldehydes with hydroxyl amine hydrochloride and sodium azide. Our results (Fourier transform‐infrared, inductively coupled plasma‐optical emission spectroscopy, powder X‐ray diffraction, field emission‐scanning electron microscopy, energy‐dispersive X‐ray spectroscopy‐mapping and vibrating‐sample magnetometer) show successful partial metal‐exchange in which the framework integrity remained intact during the metal‐exchange process.     

Condensation of an ideal gas with intermediate statistics on the horizon

We consider a boson gas on the stretched horizon of the Schwartzschild and Kerr black holes. It is shown that the gas is in a Bose?CEinstein condensed state with the Hawking temperature T _c =T _H if the particle number of the system be equal to the number of quantum bits of space-time $N \simeq{A}/{l_{p}^{2}}$ . Entropy of the gas is proportional to the area of the horizon (A) by construction. For a more realistic model of quantum degrees of freedom on the horizon, we should presumably consider interacting bosons (gravitons). An ideal gas with intermediate statistics could be considered as an effective theory for interacting bosons. This analysis shows that we may obtain a correct entropy just by a suitable choice of parameter in the intermediate statistics.     

Synthesis and characterization of nanostructural CuS–ZnS binary compound thin films prepared by spray pyrolysis

We have investigated the effect of zinc concentration ([Zn]/[Cu]=0–100 at%) on nanostructural, optical and electrical properties of CuS–ZnS binary thin films grown on glass substrate by the spray pyrolysis technique. X-ray diffraction analysis showed that the films were crystallized with mixed structures of CuS hexagonal and ZnS cubic structure. UV–vis optical measurements analysis showed that these binary films have a relatively high absorption coefficient (～10⁵ cm^?1) in the visible spectrum with a direct band gap in the range of 2.57–2.45 eV in agreement with the corresponding room temperature PL spectra. The electrical studies showed that all these samples have a p-type conductivity and the free hole density decreases with increasing [Zn]/[Cu] molar ratio, in agreement with the reflectance spectra of the layers, originating from plasma oscillations.     

Multichannel RRKM-TST and CVT rate constant calculations for reactions of CH2OH or CH3O with HO2

The kinetics and mechanism of the gas-phase reactions between hydroxy methyl radical (CH(2)OH) or methoxy radical (CH(3)O) with hydroproxy radical (HO(2)) have been theoretically investigated on their lowest singlet and triplet surfaces. Our investigations indicate the presence of one deep potential well on the singlet surface of each of these systems that play crucial roles on their kinetics. We have shown that the major products of CH(2)OH + HO(2) system are HCOOH, H(2)O, H(2)O(2), and CH(2)O and for CH(3)O + HO(2) system are CH(3)OH and O(2). Multichannel RRKM-TST calculations have been carried out to calculate the individual rate constants for those channels proceed through the formation of activated adducts on the singlet surfaces. The rate constants for direct hydrogen abstraction reactions on the singlet and triplet surfaces were calculated by means of direct-dynamics canonical variational transition-state theory with small curvature approximation for the tunneling.     

Isocyanide‐based three‐component synthesis of functionalized 5‐alkylimino‐2,5‐dihydrofuran‐3,4‐dicarboxylate and their conversion to substituted furanones

The zwitterionic 1:1 intermediates formed from alkyl isocyanides and acetylenic esters are trapped by alkyl bromides to form 5‐alkylimino‐2,5‐dihydrofuran‐3,4‐dicarboxylate in relatively good yields at room temperature under solventless conditions. Hydrolysis of these compounds by HCl (5%) produced substituted furanones. J. Heterocyclic Chem., (2011).     

Function–Topology Relationship in the Catalytic Hydrolysis of a Chemical Warfare Simulant in Two Zr-MOFs

Owing to their high surface area, high concentration of active metal sites, and water stability, zirconium(VI)-based metal–organic frameworks (Zr-MOFs) have shown excellent activity in the hydrolysis of organophosphorus nerve agents (OPNs). In this regard, for the first time, two topologically different Zr-MOFs (Zr-fcu-tmuc and Zr-bcu-tmuc, constructed from the same organic and inorganic building blocks; fcu=face-centered cubic, bcu=body-centered cubic) have been rationally chosen to investigate the effect of network topology on the catalytic hydrolysis of the nerve agent simulant, dimethyl 4-nitrophenyl phosphate (DMNP). A remarkable enhancement in the hydrolysis rate of DMNP was observed with Zr-bcu-tmuc, reducing the half-life more than three-fold compared with Zr-fcu-tmuc. Greater accessibility of the active Zr^VI sites in the 8-connected bcu net compared with the 12-connected fcu leads to a faster hydrolysis of DMNP on Zr-bcu-tmuc. Interestingly, the higher activity of Zr-bcu-tmuc was also confirmed by its higher fluorescence sensitivity towards DMNP (limit of detection (LOD)=0.557 μm ) compared with Zr-fcu-tmuc (LOD=1.09 μm ). The results show that controlling the desired topology of Zr-MOFs is a useful strategy for improving their performance in the detection and catalytic detoxification of OPNs.     

Caffeine-H3PO4: a novel acidic catalyst for various one-pot multicomponent reactions

Research on Chemical Intermediates - Caffeine-H3PO4 along with caffeine-HClO4 and caffeine-HNO3 have been prepared and applied for one-pot preparation of bis(indolyl) methanes,...