Reactivity of Thioglycolic Acid Physically and Chemically Bound to Silica Gel as New Selective Solid Phase Extractors for Removal of Heavy Metal Ions From Natural Water Samples

A method is presented for the immobilization of thioglycolic acid moiety on the surface of active silica gel via a simple and direct synthetic route and based on one step reaction procedure. Two-product solid phase extractors were successfully synthesized according to physical adsorption and chemical immobilization binding techniques, phases (I) and (II), respectively. The mode of interaction between the silanol group and the thioglycolic moiety was also discussed for both phases based on the infrared analysis studies. The thermal stability properties as well as the effect of buffer solutions on the percentage hydrolysis of the two silica gel phases were examined and revealed the high stability and superiority of silica phase (II) in these respects. The evaluation of the selectivity and metal uptake properties incorporated in these two silica gel phases were also studied and discussed for a series of divalent heavy metal ions under different controlling factors. The mmol/g values were found to be higher in case of phase (I). The selective removal and extraction of some heavy metal ions, viz . Cu(II), Zn(II), and Hg(II) from natural seawater samples was successfully accomplished with the percentage recovery values for the three tested metal ions in the range of 96.5-98.4 - 0.2-0.6%. The presence of higher concentrations of Na(I), K(I), Mg(II) and Ca(II) showed insignificant role or no matrix effect on such selective extraction process due to their 0% values of removal by these silica gel phases (I) and (II).     

Application of Secondary Amines in the Synthesis of Some New Spiro Heterocyclic Compounds

1-Anilinocycloalkanecarbonitriles 1a–c were prepared and reacted with active methylene reagents to give compounds 5a–c through 10a–c and reacted with different other reagents such as benzaldehyde, ethyl aminoacetate, ethyl mercaptoacetate, or hydrazine carbothioamide, which afforded the desired spiro heterocycles compounds 11a–c through 14a–c.     

The Reaction of Phosphonium Ylids with o-Quinones and Triketones

Abstract

The reaction of 1,2-benzo [a] phenazine-8, 9-dione 1 and/or 1,2,3-indantrione 2, with phosphonium ylides has been studied. When 1 was reacted with two molar amounts of methoxy-(3a) and/or ethoxycarbonylmethylenetriphenylphosphorane (3b), in THF, at the reflux temp, for 3 hrs, dimethyl (4a) and/or diethyl 1,2-dihydrobenzo a furo [3,2-h] phenazine-1,2-dicarboxylate (4b), along with triphenylphosphine oxide and triphenylphosphine were obtained. On the other hand, reaction of equimolar amounts of ylides 3 with the red trione 2 in THF at room temp., afforded colourless crys tals of 2′,4′-dihydroxyspiro [indan-2,3′ (2′H)-indeno [1,2-b] pyran]-1,3,5′(4′H)-trione diacetate (5a) or dipropionate (5b), together with triphenylphosphine oxide. Formation of 6-membered dihydro aromatic ring like 5, is considered as a new reaction of phos phoranes. The structure of the new compounds 4 and 5 was confirmed and the reaction mechanisms are discussed.     

Natural products in treatment of ulcerative colitis and peptic ulcer

Ulcerative colitis is an inflammatory chronic disease that affects the mucosa and submucosa of the colon and rectum. Several types of drugs are available such as aminosalicylates. Peptic ulcer disease (PUD) is a common disorder that affects millions of individuals worldwide and it can be considered one of the most important common diseases in the world. Treatment of peptic ulcers depends on using a number of synthetic drugs that reduce the rate of stomach acid secretion (Antiacids), protect the mucous tissues that line the stomach and upper portion of the small intestine (Demulcents) or to eliminate Helicobacter pylori (H. pylori). In most cases, incidence of relapses and adverse reactions is seen in the following synthetic antiulcer therapy. Accordingly, the main concern of the current article is to introduce a safe drug (or more) of natural origin, to be used for the management of gastric ulcers without side effects.A widespread search has been launched to identify new anti-ulcer therapies from natural sources. Herbs, medicinal plants, spices, vegetables and crude drug substances are considered to be a potential source to control various diseases including gastric ulcer and ulcerative colitis. In the scientific literature, a large number of medicinal plants and their secondary metabolites with potential anti-ulcer (anti-peptic ulcer and antiulcerative colitis) activities have been reported. Treatment with natural products produces promising results and fewer side effects. Our goal is to collect the published data in the last 24 years and reviews the natural products reported in the treatment of these diseases and their mechanism of action.     

Synthesis of Phosphonodithioate,Oxathiaphosphinin, Oxathiaphosphole,and Dithiaphosphole Derivatives from the Reaction of Lawesson's Reagent with Phenolic Mannich Bases and Oxime Derivatives

The reaction of Lawesson's reagent 1a, with niclosamide 2 proceeded by thionation and formation of carbothioamide 3 and the zwitterionic oxathiaphosphinin 4a. LR reacted with 8-hydroxyquinoline (5), 2-methylquinoline-4-ol (7), and β-naphthol (9) to give the phosphonodithioates 6, 8, or 10. The reaction of LR with the Mannich bases 11 and 14 afforded the oxathiaphosphinins 13 and 15, whereas the phosphonodithioates 17 and 19 were isolated in the case of Mannich bases 16 and 18. LR reacted with phthalimide Mannich base 20 to give the dithione 21 and N-methylphthalimide (22). Reaction of ketone monoxime 23 with LR resulted in the formation of the oxathiaphosphole 24 and the dithiaphosphole 25, whereas the monoxime 26 afforded the thioxoethanone thioxime 27. Ketone dioximes 28 and 34 afforded the phosphonodithioates 29 and 36, respectively, when they were allowed to react with LR, whereas the dioxime 30 gave compounds 32 and 33. Moreover, the molluscicidal potency of the newly synthesized compounds against Biomphalaria glabrata snails was studied, too.     

Separation of dietary omega‐3 and omega‐6 fatty acids in food by capillary electrophoresis

A lower dietary omega‐6/omega‐3 (n‐6/n‐3) fatty acid ratio (<4) has been shown to be beneficial in preventing a number of chronic illnesses. Interest exists in developing more rapid and sensitive analytical methods for profiling fatty acid levels in foods. An aqueous CE method was developed for the simultaneous determination of 15 n‐3 and n‐6 relevant fatty acids. The effect of pH and concentration of buffer, type and concentration of organic modifier, and additive on the separation was investigated in order to determine the best conditions for the analysis. Baseline separations of the 15 fatty acids were achieved using 40 mM borate buffer at pH 9.50 containing 50 mM SDS, 10 mM β‐cyclodextrin, and 10% acetonitrile. The developed CE method has LODs of <5 mg/L and good linearity (R² > 0.980) for all fatty acids studied. The proposed method was successfully applied to the determination of n‐3 and n‐6 fatty acids in flax seed, Udo® oils and a selection of grass‐fed and grain‐fed beef muscle samples.     

Synthesis of Pyrimidine,Dihydropyrimidinone, and Dihydroimidazole Derivatives under Free Solvent Conditions and Their Antibacterial Evaluation

The biologically active compounds of pyrimidine, dihydropyrimidinone, and dihydroimidazole have been synthesized in excellent yield under free solvent conditions. The antibacterial evaluation of the products showed a high inhibitory effect. Reaction of 2‐guanidinobenzothiazole with several active methylene compounds has revealed formation of the corresponding pyrimidine, dihydropyrimidinone, and dihydroimidazole derivatives under free solvent conditions in very good yield. All compounds have been characterized on the basis of IR, ¹H NMR, ¹³C NMR, mass spectrometry, and X‐ray.     

Performance of flowing sample neutron activation analysis technique for determination of multi-elemental content

In order to measure and obtain reliable data about elements via measuring of short-lived isotopes in liquid samples using neutron activation analysis, experiments have been carried out using a flowing sample neutron activation analysis method. During this work the performance and reliability for the proposed method have been tested using synthetic multi elements liquid samples. The radionuclide, associated elements and their concentration level have been measured using a counting system with a fixed dead-time. An HPGe spectrometry system was used to determine the most important γ-ray energies and intensities of these isotopes. The obtained results demonstrated the reliability and accuracy (bias <5 % and zeta score <2) of the tested method for determination the elemental content of liquid samples.     

纯相和镍取代的Co_3O_4尖晶石催化剂用于N_2O直接分解(英文)

A series of NixCo1-xCo2O4(0 ≤ x ≤ 1) spinel catalysts were prepared by the co-precipitation method and used for direct N2O decomposition. The decomposition pathway of the parent precipitates was characterized by thermal analysis. The catalysts were calcined at 500 °C for 3 h and characterized by powder X-ray diffraction, Fourier transform infrared, and N2 adsorption-desorption. Nickel cobaltite spinel was formed in the solid state reaction between NiO and Co3O4. The N2O decomposition measurement revealed significant increase in the activity of Co3O4 spinel oxide catalyst with the partial replacement of Co2+ by Ni2+. The activity of this series of catalysts was controlled by the degree of Co2+ substitution by Ni2+, spinel crystallite size, catalyst surface area, presence of residual K+, and calcination temperature.     

Thermodynamic properties of a rotating Bose gas in harmonic trap

In this paper, the thermodynamic properties of a rotating Bose gas in harmonic trap are investigated. In particularly, the condensate fraction, critical temperature and heat capacity are analytically calculated. A simple semiclassical approximation, which is the density of state approach, is suggested. This approach is able to include the effects, such as the finite size and the chemical potential when becomes equal to the energy of the lowest energy state, that altered the rotating ideal Bose gas simultaneously. The calculated results show that the thermodynamic properties depend strongly on the rotation rate. The rapid rotation leads to a highly anisotropic confinement potential. The possibility for dimensionality cross-over to lower dimensions for this system is discussed. We compare the outcome results with the experimental measured data of Coddington et al. [Phys. Rev. A 70, 063607 (2004)].