Synthesis,crystal structure,cholinesterase inhibitory activity,evaluation of insecticidal activities,and computational studies of new phosphonic acids

Molecular Diversity - In an attempt to obtain the modified and novel insecticides with low human toxicity, a series of novel mono-, bis-, and tetraphosphonic acid derivatives were designed and...     

60, 90 and 250 MHz 1H NMR spectra of sultams and sultones

The high-field ¹H NMR spectra of 1,3-propanesultams (2), 2,4-butanesultams (3) and 2,4-dimethyl-1,3-butadienesultams (6) are reported. Comparison of 2,3 and 6 with 1,3-propanesultone (1) and 2,4-dimethyl-1,3-butadienesultone (5) reveals that the paramagnetic shift induced by the NH group is smaller than that induced by oxygen. NMR spectra at lower temperature show coupling effects with the NH proton. A half-chair conformation was deduced for 2,4-butanesultam from coupling constants and from a conformational analysis based on the R values, but a chair-chair interconversion could not be detected in the temperature range between 210 and 330 K. An unambiguous assignment was carried out for the methyl signals in the spectrum of 5 by homodecoupling experiments.     

On the Synthesis of 3-Acetyl-1-aryl-1,4,5,6-tetrahydro-1<Emphasis Type="Italic">H</Emphasis>-1,2,4-triazepin-7-ones by Reaction of Nitrilimines with 3-Aminopropanoic Acid

Summary. Nitrilimines were prepared from N-arylhydrazono chlorides and reacted with -alanine yielding the corresponding amidrazones, which were treated with 1,1-carbonyldiimidazole in THF affording the hitherto unknown 3-acetyl-1-aryl-1,4,5,6-tetrahydro-1,2,4-triazepin-7-ones.     

Détermination directe des constantes cinétiques d'une réaction chimique par microcalorimétrie à conduction application à la saponification des diesters

The kinetic study of competitive consecutive reactions presents difficulties owing to the complexity of the mathematical integration of differential equation systems. Many investigators adopted methods using graphs of experimental data to determine the kinetic constants of a reaction. We propose, in this work, a direct determination of these constants based on thermograms recorded with a Calvet conduction microcalorimeter using a computing program which includes numerical integration of differential equation systems, signal convolution with an experimental function of apparatus (to get rid of the inertness of the detector—recorder system) and the optimization of the adopted model parameters. We applied this exploitation process to the alkaline hydrolysis of some diester of diols or dicarboxylic acids in aqueous solution.     

Calorimetric studies of AgI-doped tellurite glasses

The heat capacity changes during the glass transition of TeO₂---TlO_0.5 glasses containing AgI or (AgI)_0.75(TlI)_0.25 up to mole fractions of 0.4 or 0.55 have been measured by differential scanning calorimetry. The glass transition temperatures of the binary compositions decrease with increasing TlO_0.5/TeO₂ ratio. With rising Ag⁺ concentration, the cohesion of the glass network is weakened and the structural contributions to the relaxation phenomenon as well as its activation enthalpies diminish. There is no interaction between the iodide in probably crystalline form and the host glass network. Compared with binary and ternary silver tellurite glasses, the corresponding thallium tellurite compositions are less stable.     

A mild and clean Baeyer–Villiger oxidation of ketones using sodium peroxydisulfate as oxidant catalyzed by silica-supported aluminum chloride

Sodium peroxydisulfate was used as the oxidant for Baeyer?CVilliger oxidation of a variety of cyclic and acyclic ketones at room temperature in the presence of Silica-supported aluminum chloride (silica-AlCl₃) as catalyst. The catalyst was prepared by a simple procedure, which exhibited high catalytic activity for the Baeyer?CVilliger oxidation of ketones using environmental friendly sodium peroxydisulfate as oxidizing agent.     

An eco-friendly procedure for one-pot synthesis of β-phosphonomalonates: micellar solution of sodium stearate catalyzes tandem Knoevenagel-phospha-Michael reaction of aldehydes, malonitrile, and phosphites in aqueous media

A new, one-pot convenient method for the synthesis of a variety of β-phosphonomalonates by a tandem Knoevenagel-phospha-Michael reaction of phosphite esters with aryl/heteroaryl/alkyl aldehydes and malonitrile in an aqueous micellar solution of sodium stearate is described. This method offers several advantages, such as using a cheap and environmentally benign reaction media, low loadings of sodium stearate as catalyst and offers good yields.