Design,Synthesis, Molecular Modeling Study,and Antimicrobial Activity of Some Novel Pyrano[2,3‐b]pyridine and Pyrrolo[2,3‐b]pyrano[2.3‐d]pyridine Derivatives

Novel derivatives of pyrano[2,3‐b]pyridine and pyrrolo[2,3‐b]pyrano[2.3‐d]pyridine were prepared, and their structures were elucidated by spectral and elemental analyses. The newly prepared candidates were evaluated for their antimicrobial activity against Candida sp., Aspergillus multi, Aspergillus niger, Escherichia coli, and Staphylococcus aureus. All the tested compounds revealed potent to moderate activity toward all tested microorganisms; especially, candidate 10 showed comparable antifungal activity as that showed by the standard drug ketoconazole toward Candida sp., and ethyl 4‐methyl‐1,7,8,9‐tetrahydropyrano[2,3‐b]pyrrolo[2,3‐d]pyridine‐3‐carboxylate ( 12 ) was the most active compound against all the tested bacteria. Furthermore, the newly synthesized compounds are subjected to molecular docking study for the inhibition of the enzyme L‐glutamine: D‐fructose‐6‐phosphate amidotransferase [GlcN‐6‐P], which is a new target for antimicrobials to explain action mode of these target compounds as leads for discovering other antimicrobial agents.     

Screening and determination of drugs in human saliva utilizing microextraction by packed sorbent and liquid chromatography–tandem mass spectrometry

This study presents a new method for collecting and handling saliva samples using an automated analytical microsyringe and microextraction by packed syringe (MEPS). The screening and determination of lidocaine in human saliva samples utilizing MEPS and liquid chromatography–tandem mass spectrometry (LC‐MS/MS) were carried out. An exact volume of saliva could be collected. The MEPS C₈‐cartridge could be used for 50 extractions before it was discarded. The extraction recovery was about 60%. The pharmacokinetic curve of lidocaine in saliva using MEPS‐LC‐MS/MS is reported. Copyright © 2013 John Wiley & Sons, Ltd.     

Biological Effect,Aquation, and Kinetics of Oxidation of Bis(2‐aminobenzothiazole)dichlorocobalt(II) Complex by Periodate in Aqueous Acidic Medium

The biological effect, aquation, and kinetics of oxidation of bis(2‐aminobenzothiazole)dichlorocobalt(II) complex by periodate in aqueous acidic solutions were studied. The complex exhibited a broad resistance toward the studied pathogens. The average value of the aquation constant was calculated spectrophotometrically as 2.55 × 10^?5 mol² dm^?6. Kinetics of the oxidation reaction showed first‐order dependence on each reactant concentration and increased by increasing pH over the 3.80–4.80 range, 35–50°C, and decreased by increasing the ionic strength over the 0.1–0.5 mol dm^?3 range. The polymerization of acrylonitrile was taken as an evidence for an inner‐sphere mechanism through the formation of free radical intermediates of Co(III) complexes, which were slowly converted to the final Co(III)products.     

Novel Uncatalyzed Hydrocyanation of Ketones utlizing Tetrachlorosilane–Potassium Cyanide Reagent

A combination of tetrachlorosilane and potassium cyanide (in situ trichlorosilyl cyanide) was found to work efficiently for hydrocyanation of ketones to afford the corresponding cyanohydrins in high yield under mild conditions.     

Flow-injection spectrophotometric determination of chloramben

Abstract

A method for the dechlorination of PCB mixtures (Aroclor formulations) to biphenyl was extended to soils. The contaminated sample was mixed with magnesium flakes, potassium hexachloropalladiate (K₂PdCl₆), propan-2-ol and water then permitted to react for up to six hours. Biphenyl, recovered by extraction into hexane, was quantified by gas chromatography with flame ionization detection. The reaction was very efficient in propan-2-ol / water (～95%), surfactant emulsion or sand mixture and virtually complete in soil provided that excess magnesium (2 g) and the K₂PdCl₆ were added to the sample prior to the addition of water. Higher PCB loadings were readily determined in field contaminated soils either by direct determination within the matrix or by standard additions. However, analyte concentrations were appreciably over-estimated in Soxhlet or sonication extracts of a certified reference material that contained sub-ppm levels of analyte. The over-estimation is considered to result from the conversion in part of natural organic matter to biphenyl.     

Conversion of biomass residual to acid-modified bio-chars for efficient adsorption of organic pollutants from industrial phosphoric acid: an experimental,kinetic and thermodynamic study

ABSTRACT

This study reports the removal of organic matters from phosphoric acid using waste-produced bio-charcoal structures. Particularly, the freshly made bio-char species via pyrolysis and two sub-driven acids activated charcoals were applied during the removal process. The treated charcoal with hydrochloric and nitric acids had attained a higher adsorption rate for organic matters than that of the non-treated one. Removal percentages of 70% and 60% were, respectively, attained by acid-modified chars. The kinetics of the adsorption process was fitted via pseudo-first/second-order and Morris–Weber models. The thermodynamic parameters of the presented sorption process indicate that organic matter removal has been endothermic, physical and spontaneous.     

Tuning the mesogenic properties of 5-alkoxy-2-(4-alkoxyphenyl)pyrimidine liquid crystals: the effect of a phenoxy end-group in two sterically equivalent series

Two sterically equivalent series of phenoxy-terminated 5-alkoxy-2-(4-alkoxyphenyl)pyrimidine liquid crystals were synthesised, and their mesogenic properties were characterised by polarised optical microscopy and differential scanning calorimetry (DSC). The phenoxy end-group causes a significant increase in melting point and inhibits – at least partially – the mesomorphism of these materials relative to the parent isomers; in most cases, the broad enantiotropic SmC phase formed by the parent isomers is suppressed by the addition of the phenoxy end-group. However, detailed analyses by small-angle X-ray scattering and monodomain 2D X-ray scattering suggest that these compounds form a SmA phase with a partially intercalated bilayer structure in which the phenoxy end-groups are nanosegregated. Such an intercalated bilayer structure might enable the tuning of smectogenic properties by appropriate substitution of the phenoxy end-groups.     

The first molybdenum dioxo compounds with eta 2-pyrazolate ligands: crystal structure and oxo transfer properties

Molybdenum dioxo compounds [MoO2Cl(eta 2-pz)] and [MoO2(eta 2-pz)2] with pz = eta (2)-3,5-di-tert-butylpyrazolate have been synthesized; crystallographic data, catalytic activity, and oxo transfer properties are described.     

Environmental certification: a scientific tool for sustainability. Evaluation of possible indicators for the environmental performance evaluation (EPE) of Ravenna province (Italy)

Environmental certification is becoming the main tool for application of sustainable development principles. The European Regulation Emas and the international standard ISO 14001 both require for certification, to perform an environmental management system to prevent environmental impacts and to continuously improve environmental performance. For a good environmental performance evaluation (EPE), certification needs to use scientific methodologies and to interface with scientific research; here we proposed emergy analysis as a valid method for EPE and emergetic environmental performance and condition indicators (EPIs, ECIs) to monitor a territorial system: Ravenna province (Italy). Together with emergy indicators were selected other indicators for a deeper EPE: emitted/adsorbed CO2, energy consumptions, air and water pollution measures. The paper showed that Ravenna system has a good environmental performance and demonstrated how different indicators from the most advanced chemical research (chemical-physical, analytical, etc.) contribute to a complete EPE of a complex territorial system and are useful for environmental certification and sustainable development.     

Steric substituent effect on the resin catalyzed hydrolysis of alkyl acetate esters

The rates of hydrolysis of seven acetate esters substituted in the alkyl group have been studied in the presence of a sulfonated cation exchange resin in 70% aqueous acetone solution. the slower hydrolysis rates with increasing size of substituent are related to increasing steric influence, as determined by decreasing values of the steric substituent parameter, E_s. The efficiency of the resin catalyst is related to the entropy of substituents. Influence caused by steric hindrance on reaction rates accounts satisfactorily for observed variations of the enthalpies and entropies of activation with alkyl group substituents. The entropy, S^x, values increase in the order: n-octyl-

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