Intramolecular hydrogen bonding in 3‐imino‐propenylamine: Theoretical investigations

Intramolecular H‐bonds existing for derivatives of 3‐imino‐propenylamine have been studied using the B3LYP/6‐311++G** level of theory. The nature of these interactions, known as resonance‐assisted hydrogen bonds, has been discussed. Vibrational frequencies for α‐derivatives were calculated at the same level of theory. The topological properties of the electron density distributions for N? H···N intramolecular bridges have been analyzed in terms of the Bader theory of atoms in molecules (AIM). Calculation for 3‐imino‐propenylamine derivatives in water solution were also carried out at B3LYP/6‐311++G** level of theory. Finally, the analysis of hydrogen bond in this molecule and their derivatives by quantum theory of natural bond orbital methods fairly support the ab initio results. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009     

Fabrication of a high sensitive glycine electrochemical sensor based on immobilization of nanostructured Ni chelidamic acid and bimetallic Au-Pt inorganic-organic hybrid nanocomposite onto glassy carbon modified electrode

In this research a novel nickel complex was used as electrocatalyst for electrooxidation of glycine. A nano-structured nickel chelidamic acid was electrodeposited on a bimetallic Au-Pt inorganic-organic hybrid nanocomposite modified electrode. The electrode possesses a three-dimensional (3D) porous network nanoarchitecture, in which the bimetallic Au-Pt NPs serving as metal nanoparticle based microelectrode ensembles are distributed in the matrix of interlaced 3,3′,5,5′-tetramethylbenzidine (TMB) organic nanofibers (NFs). Electrocatalytic oxidation of glycine on the surface of modified electrode was investigated with cyclic voltammetry method and the results showed that the nickel chelidamic acid films displayed excellent electrochemical catalytic activities towards glycine oxidation. The hydrodynamic amperometry at rotating modified electrode at constant potential versus reference electrode was used for detection of glycine. Under optimized conditions the calibration plots are linear in the concentration range 1 μM-0.75 mM and detection limit was found to be 0.3 μM.     

Base induced cyclization of some quinolines. Formation of fused nitrogen heterocyclic ring system

Condensation of 3,5-dinitro-4-chloro-6-methoxy-2-methylquinoline (1) with benzylamine, ethanolamine and/or thioglycolic acid afforded the quinoline derivatives4 a-c. Cyclization of4 a and4 b with alkali and condensation of1 with glycine in sodium carbonate solution furnish 2H-imidazo[4,5-c]quinoline derivatives5 a-c, respectively. Treatment of5 b with benzaldehyde in presence of zinc chloride gave the styryl derivative6. 1 reacted with sodium azide to give the azido derivative4 d, which upon treatment with phenylhydrazine or sodium borohydride yielded the 4-amino derivative4 3. Moreover,1 was treated with phenylhydrazine to give4 f, which cyclized in 10% sodium hydroxide solution to the corresponding v-triazolo[4,5-c]quinoline 3-oxide derivative7. When however4 f was treated with dilute hydrochloric acid, the corresponding phenylpyrazolo[3,4,5-de]quinoline derivative8 was obtained.

---

Baseninduzierte Cyclisierung einiger Chinoline. Darstellung höherer Stickstoff-Heterocyclen

Zusammenfassung Kondensation von 3,5-Dinitro-4-chlor-6-methoxy-2-methylchinolin (1) mit Benzylamin, Ethanolamin und/oder Thioglycolsäure ergab die Chinolinderivate4 a-c. Cyclisierung von4 a und4 b mit Alkali und Kondensation von1 mit Glycin in Natriumcarbonatlösung lieferte 2H-imidazo[4,5-c]chinolin-Derivate5 a-c. Behandlung von5 b mit Benzaldehyd in Gegenwart von Zinkchlorid ergab das Styrylderivat6. 1 wurde mit Natriumazid zum Azidoderivat4 d umgesetzt, das mit Phenylhydrazin oder Natriumborhydrid zum 4-Aminoderivat4 e weiterreagierte.1 ergab mit Phenylhydrazin4 f, das in 10% NaOH-Lösung zum entsprechenden Triazolo[4,5-c]chinolin-Derivat7 cyclisierte. Aus4 f wurde mit verdünnter Salzsäure das Phenylpyrazolo[3,4,5-de]chinolin8 erhalten.

     

A Review in Linear Alkylbenzene (LAB) Production Processes in the Petrochemical Industry

Russian Journal of Applied Chemistry - Linear alkylbenzene (LAB) is a cost-effective and biodegradable intermediate in the production of detergents and surfactants. Recently, due to the spread of...     

Role of Vitamins B-3 and C in the Fashioning of Granules in UASB Reactor Sludge

Whereas a myriad of possible factors have been reported which effect the formation of granules in a upflow anaerobic sludge blanket (UASB) reactor and influence their properties, there is no study on the effect of vitamins on the granulation of UASB reactor sludge. The present study was undertaken to bridge this gap. It was seen that vitamins helped in better granule formation??as reflected by favorable size distribution, sludge volume index, and settling velocity??compared to controls. The vitamin-spiked reactors also achieved >85?% COD removal efficiency in half the number of days the unspiked reactors took. The vitamin supplements were effective at concentrations????1?mg/l. Hence, their use in expediting granule formation as also in developing better-quality granules appears economically viable.     

On copositive approximation in some classical spaces of sequences

In this paper the author writes a simple characterization for the best copositive approximation in c; the space of convergent sequences, by elements of finite dimensional Chebyshev subspaces, and shows that it is unique.     

Synthesis of Some Pyrimidine 2-Oxo(Thio)-4,6-Dione Derivatives

5-Arylidenes 1a and 1b, on reaction with ethyl cyanoacetate and diethyl malonate in the presence of ammonium acetate under Michael condensation, yield pyridine derivatives 2 and 3, respectively. Cyclopentapyrimidine derivative 4 can also be obtained by the reaction of 1a with malononitrile in the presence of piperidine. The reaction of 5-arylidene lb with monochloroacetic acid in an alkaline medium gives the thiazol derivative 5. Also, spiro-[3′, 5′]cyclohexenyl pyrimidine derivative 6 could be obtained from the reaction of 1d with maleic anhydride. On the other hand, 5-arylidene 1e reacts with maleic anhydride to give 2-thiobarbituric acid derivative 7. The condensation reaction of 2-thiovioluric acid 8 with some hydrazines affords the triazole derivatives 9a-d. Finally, barbituric acid condenses with isatin to give 5-arylidene 1f, which can be cyclized with phosphorous pentoxide to afford 10.     

Aptamer Laden Liquid Crystals Biosensing Platform for the Detection of HIV-1 Glycoprotein-120

We report a label-free and simple approach for the detection of glycoprotein-120 (gp-120) using an aptamer-based liquid crystals (LCs) biosensing platform. The LCs are supported on the surface of a modified glass slide with a suitable amount of B40t77 aptamer, allowing the LCs to be homeotropically aligned. A pronounced topological change was observed on the surface due to a specific interaction between B40t77 and gp-120, which led to the disruption of the homeotropic alignment of LCs. This results in a dark-to-bright transition observed under a polarized optical microscope. With the developed biosensing platform, it was possible to not only identify gp-120, but obtained results were analyzed quantitatively through image analysis. The detection limit of the proposed biosensing platform was investigated to be 0.2 µg/mL of gp-120. Regarding selectivity of the developed platform, no response could be detected when gp-120 was replaced by other proteins, such as bovine serum albumin (BSA), hepatitis A virus capsid protein 1 (Hep A VP1) and immunoglobulin G protein (IgG). Due to attributes such as label-free, high specificity and no need for instrumental read-out, the presented biosensing platform provides the potential to develop a working device for the quick detection of HIV-1 gp-120.     

Convergent synthesis of carbonic anhydrase inhibiting bi-heterocyclic benzamides: Structure–activity relationship and mechanistic explorations through enzyme inhibition,kinetics, and computational studies

By using a convergent methodology, a novel series of N-arylated 4-yl-benzamides containing a bi-heterocyclic thiazole–triazole core was synthesized, and the structures of these hybrid molecules, 9a–k , were corroborated through spectral analyses. The in vitro studies of these multifunctional molecules demonstrated their potent carbonic anhydrase inhibition relative to the standard used. The kinetics mechanism was exposed by Lineweaver–Burk plots, which revealed that 9j inhibited carbonic anhydrase non-competitively by forming an enzyme-inhibitor complex. The inhibition constants K_i calculated from Dixon plots for this compound was 1.2 μM. The computational study was also persuasive with the experimental results, and these molecules disclosed good results of all scoring functions and interactions, which suggested a good binding to carbonic anhydrase. So, it was predicted from the inferred results that these molecules might be considered as promising medicinal scaffolds for various diseases related to the uncontrolled production of this enzyme.