Polyethylene Glycol (PEG 300) and Water–Ethanol as Benign Solvent Systems for the Synthesis of a Novel Series of 2-Hydroxynaphthalen-1(4H)-Ones

An improved, clean, simple, and efficient method for the synthesis of new series of 2-hydroxy-4-methylenenaphthalen-1(4H)-one is described. This new process involves a domino Michael addition of various methylene acid compounds with the sodium salt of 1,2-naphthoquinone-4-sulfonate either in basic (tBuOK) polyethylene glycol (PEG300) at room temperature or in a basic (NaOH) water–ethanol medium at 40 °C by a crushing in a mortar or a traditional heating.     

Multiresidue analysis of atrazine, diuron and their degradation products in sewage sludge by liquid chromatography tandem mass spectrometry

A multiresidue method has been developed to analyze atrazine (ATZ), diuron (DIU), and their major degradation products, desethylatrazine (DEA), desisopropylatrazine (DIA), and dichlorophenylmethylurea in sewage sludge. Liquid chromatography coupled to electrospray tandem mass spectrometry (LC–ESI-MS–MS) allowed, in the multiple-reaction monitoring mode, the simultaneous analysis of these pesticides in only one run after their extraction with ethyl acetate–dichloromethane 90:10 (v/v) and a cleanup on a Florisil column. Stable isotopically labeled ATZ and DIU were used as internal standards to overcome matrix effects during the pesticide quantification. Using fortified samples, the method gave rise to 86–115% as mean recovery values depending on the analyte. Limits of detection (LODs) and of quantification (LOQs) ranging from 0.3 (DIA) to 1.5 (DEA) μg kg⁻¹ dw and from 0.4 (DIA) to 2.0 (DEA) μg kg⁻¹ dw, respectively, were sufficient to achieve the monitoring of these molecules in sludge from wastewater treatment plants of the Ile-de-France region.     

One-pot green synthesis,study of fluorescence properties,and biological activity of pyrano[3,2-c]chromenes derivatives via mesoporous materials MgO/SBA-15

This current work describes the preparation of MgO-SBA-15 catalysts by ultrasonic method, and it is characterized by the different analysis techniques of XRD, BET, SEM, and IRTF. In order to find out an application for this mesoporous material, MgO/SBA-15 was used as a heterogeneous catalyst in the one-pot synthesis of pyrano[3,2-c]chromenes derivatives isolated at room temperature reaction according to green chemistry criteria. To enhance these derivatives, a spectroscopic study of molecular fluorescence properties was carried out as well as an identification analysis by nuclear magnetic resonance and FTIR was used. Furthermore, biological activity experiment is also carried out, from where the obtained test results were satisfactory for AC09 , AC05 , and AC10 compounds and they are checked after computation by molecular modeling.     

Silicon-on-insulator eight-channel optical multiplexer based on a cascade of asymmetric Mach-Zehnder interferometers

A monolithically integrated eight-channel optical multiplexer (Mux) with a 400 GHz channel spacing ~1550 nm is presented based on a silicon-on-insulator rib waveguide and an asymmetric Mach-Zehnder interferometer. All channels were optimized independently with integrated heaters. The fully tuned Mux shows an adjacent channel isolation of ~13 dB, an excess loss of ~2.6 dB, and a channel uniformity of ~1.5 dB over a 25 nm wavelength span. In addition, the phase tuning efficiency for different interlevel dielectric layer thicknesses and thermal crosstalk were investigated.     

Derivation of a double integral via convolution of Student t-densities

The Ramanujan Journal - In this paper, we establish a quicker approximation with continued fraction and some inequalities for the gamma function based on Windschitl’s formula. We also give...     

Une synthèse générale des tétraazamacrocycles mono-C-fonctionnalisés

A General Synthesis for Mono-C-Functionalized Tetrazamacrocycles A new synthesis, under usual conditions of concentration, medium, and temperature, of a series of mono-C-functionalized tetraazamacrocycles is given. The method may easily be generalized. The new procedure allows the modification of the length of the side-chain or the size of the cavity by choosing fitted staring materials. The key intermediate has a tosylated linear side-chain susceptible to be transformed into a large variety of functional groups.     

Mesophase study of pure and doped cyanobiphenyl liquid crystals with salen-type systems

Two salen Schiff base ligands derived from the condensation of ethylendiamine on salicylaldehyde and 5-chlorosalicylaldehyde, namely N,N′-bis(salicylidene)ethylene-diamine (L1) and N,N′-bis(5-chlorosalicylidene)ethylene-diamine (L2) as well as two of their iron(III) and nickel(II) complexes, were prepared and then used as doping agents of two thermotropic liquid crystals (LCs) of cyanobiphenyl type, namely 4-cyano-4′-n-pentyl-biphenyl (5CB) and 4-cyano-4′-n-octyl-biphenyl (8CB). The study of the mesophase of pure and doped LCs was carried out by UV–visible spectroscopy equipped with a heating compartment for precise temperature control, differential scanning calorimetry and polarised optical microscopy. The characteristic nematic/isotropic and smectic-A/nematic transition temperatures of 5CB- and 8CB-based systems were measured and then compared to those of the literature concerning pure 5CB and 8CB. Optical microscopy results revealed the existence of Schlieren and focal conic textures of the nematic and smectic states, respectively, both of pure and doped LCs. The homogeneity of the obtained guest–host systems was proven by the linear evolution of their transition temperatures as function of the solute concentration, with correlation factors close to unity.