Synthesis of substituted 1,4-diazepines and 1,5-benzodiazepines using an efficient heteropolyacid-catalyzed procedure

An efficient and improved procedure for the synthesis of 1,4-diazepine and 1,5-benzodiazepine derivatives via the reaction of ketimine intermediates with aldehydes in the presence of Keggin-type heteropolyacids (HPAs) was developed. High yields and short reaction times were obtained for both electron-releasing and electron-withdrawing substituted 1,4-diazepine and 1,5-benzodiazepines derivatives.     

Microwave-mediated synthesis and manipulation of a 2-substituted-5-aminooxazole-4-carbonitrile library

A 2-substituted-5-aminooxazole-4-carbonitrile library has been synthesised and modified via microwave-mediated and flow chemistries. One synthesised compound, 5-(1H-pyrrol-1-yl)-4-(1H-tetrazol-5-yl)-2-(thien-2-yl)oxazole, contains three distinct heterocycles attached to the central oxazole core, highlighting the structural diversity of this approach. Three oxazoles had micromolar k_i values against cannabinoid (CB1/CB2) receptors.     

Determination of moisture content of single-wall carbon nanotubes

Several techniques were evaluated for the establishment of reliable water/moisture content of single-wall carbon nanotubes. Karl Fischer titration (KF) provides a direct measure of the water content and was used for benchmarking against results obtained by conventional oven drying, desiccation over anhydrous magnesium perchlorate as well as by thermogravimetry and prompt gamma-ray activation analysis. Agreement amongst results was satisfactory with the exception of thermogravimetry, although care must be taken with oven drying as it is possible to register mass gain after an initial moisture loss if prolonged drying time or elevated temperatures (120 °C) are used. Thermogravimetric data were precise but a bias was evident that could be accounted for by considering the non-selective loss of mass as volatile carbonaceous components. Simple drying over anhydrous magnesium perchlorate for a minimum period of 8-10 days is recommended if KF is not available for this measurement.     

Microwave-assisted synthesis of calix[4]resorcinarenes

Microwave-assisted synthesis of calix[4]resorcinarenes by cyclocondensation of various aldehydes and resorcinol catalysed by 12-tungstophosphoric acid type Keggin (H₃PW₁₂O₄₀·13H₂O) or concentrated HCl is described. Excellent isolated yields (up to 90%) were attained within short reaction times (typically, 3-5 min) when the reaction was performed under microwaves irradiation.     

Reactions with heterocyclic amidines 1. Cyanoethylation of cyclic amidines

2-Amino-5-phenyl-1,3,4-oxadiazole ( 1a ) and 2-amino-1,3,4-thiadiazole ( 1b ) reacted with acrylonitrile to yield β-cyanoethylamino derivatives. On the other hand, 2-amino-4-phenylthiazole ( 2 ) reacted with acrylonitrile under the same experimental conditions to yield a di-β-cyanoethylaminothiazole derivative. 3-Phenyl-Δ²-1,2,4-triazoline-5-thione reacted with acrylonitrile to yield the corresponding adduct. The structure of the adduct was established by its conversion into the acid 13 which could be synthesised via another independent route.     

On a Cotangent Bundle with Deformed Riemannian Extension

The main purpose of this paper is to study deformed Riemannian extensions in the cotangent bundle. The curvature properties of metric connections for deformed Riemannian extensions are also investigated.     

Rational design of a BiFeWO6 nanostructure for supercapacitor applications

Journal of Solid State Electrochemistry - Scientists are increasingly interested in improving electroactive technologies for supercapacitor applications, since energy storage devices have improved...     

Studies on molecular complexes of n-donors with iodine by the constant activity method

Iodine complexes of imidazoles in chloroform were studied by using the constant activity method. The equilibrium constants and the extinction coefficients of the complexes were determined and the results are compared with those obtained by using conventional spectral method. It was found that the equilibrium constants increase as the donor strength increases, while the extinction coefficients decrease. This behavior was interpreted in terms of molecular structure of the donor molecule.     

Substituent effects to the electrochromic behaviors of electropolymerized metallophthalocyanine thin films

Metallophthalocyanines (MPcs) (M = 2H⁺, Zn²⁺, Co²⁺, and Cu²⁺) bearing diethylaminophenoxy and chloro substituents at the peripheral positions (MPc-tdea-tCl) were coated on the working electrodes with the electropolymerization and tested as electrochromic materials. Altering the metal center of MPcs affected the redox activities of MPc-tdea-tCl films. All electropolymerized MPc-tdea-tCl films behaved as conductive and redox active films in different electrolyte systems. Electrochromic properties of MPc-tdea-tCl films were investigated via the voltammetric, in situ spectroelectrochemical, and in situ spectroelectrocolorimetric measurements. H ₂ Pc-tdea-tCl film did not give any electrochromic response, while ZnPc-tdea-tCl and CuPc-tdea-tCl films behave as a reasonable electrochromic material. Distinctive color changes with short response times, high optical contrast, and better optical and coulombic stabilities were only observed with CoPc-tdea-tCl film.