A synthetic route to 11-(1H-pyrrol-1-yl)-11H-indeno[1,2-b]quinoxaline derivatives exploiting a three-component coupling strategy under microwave irradiation

11H-Indeno[1,2-b]quinoxalin-11-ones generated in situ from ninhydrin and various 1,2-phenylenediamines, catalysed by montmorillonite K10 under microwave irradiation, condense with 4-hydroxyproline to produce 11-(1H-pyrrol-1-yl)-11H-indeno[1,2-b]quinoxaline derivatives in good yields.     

The Complexation of Lanthanides by AZO-β-Diketones Stability Constants

The stability constants of the complexes between the trivalent lanthanide series of cations and series of azo-β-diketone ligands are reported. The measurements were conducted at 30° at an ionic strength of zero, in 100% methanol. The relation between the overall stability constant (log β₂) and atomic number of the lanthanide elements, shows a buffer zone at the gadolinium area. The relation between (log β₂) and the basicity of the studied ligands (ΣpK's) are also, discussed. The overall stability values obtained reflected a great affinity of the organic ligands for chelation with lanthanide ions.     

Syntheses of New Isocephems and Isodethiaoxacephems as Antimicrobial Agents

The cis-configurated isocephem 26 as well as isodethiaoxacephems 21 and 33 were synthesized (Schemes 4 and 5). The key step involves chlorination of the corresponding carbanions of 23, 18 , and 31 with CF₃SO₂Cl followed by internal alkylation. β-Lactams 3, 21, 26 , and 33 were found to possess biological activity against several pathogenic microorganisms in vitro. Electronic activation of the lactam moiety in isodethiaoxacephem 33 remarkably enhanced its biological activity.     

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.     

Chemoselective synthesis of stable phosphorus ylides containing a β-amino group

A facile and chemoselective one-pot synthesis of stable phosphorus ylides containing a β-amino group has been developed via reaction of triphenylphosphine, dialkyl acetylenedicarboxylate and 1,2-phenylenediamine in the presence of phenol or 2-aminophenol on its own at ambient temperature.     

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.     

介孔硅铝分子筛的合成、表征及其作为固体酸催化苯酚与1-辛烯的烷基化反应

以异丙醇铝、硅酸四乙酯和十六烷基三甲基溴化胺为原料,以乙酰丙酮为螯合剂,采用溶胶-凝胶法合成了硅铝比分别为25,50,100和150的介孔硅铝分子筛,并用其催化苯酚与1-辛烯的液相烷基化反应.X射线衍射、N2吸附、高分辨透射电镜及27Al核磁共振光谱表征结果表明,该介孔分子筛具有蠕虫状骨架结构.在160℃时,硅铝比为25的介孔硅铝分子筛催化剂上苯酚可以完全转化为单烷基苯酚.     

Syntheses,spectroscopic study and crystal structures of some new <Emphasis Type="Italic">N</Emphasis>-benzoylphosphoric triamides

The reaction of N-benzoylphosphoramidic dichloride with amines afforded some new N-benzoylphos-phoric triamides with formula C₆H₅C(O)NHP(O)(X)₂, X=NH–CH(CH₃)₂ (1), NH–CH₂–CH(CH₃)₂ (2), NH–CH₂–CH(OCH₃)₂ (3), N(CH₃)[CH₂CH(OCH₃)₂] (4) and N(CH₃)(C₆H₁₁) (5) that were characterized by ¹H,¹³C,³¹P NMR, IR spectroscopy and elemental analysis. The structures have been determined for compounds 4 and 5 by X-ray crystallography. These compounds contain one amidic hydrogen atom and form centrosymmetric dimmers via intermolecular –P–O⋯H–N–hydrogen bonds besides weak C–H⋯O hydrogen bonds that lead to three-dimensional polymeric clusters in the crystalline lattice.     

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.