A novel method for the synthesis of polysubstituted diaminobenzonitrile derivatives using controlled microwave heating

A novel, simple and efficient method for the synthesis of polysubstituted diaminobenzonitriles has been developed that involves reaction of 1,1,3-tricyano-2-aminopropionitrile with nitroolefins under controlled microwave irradiation conditions.     

Magnetic methylene-based mesoporous organosilica composite-supported IL/Pd: a powerful and highly recoverable catalyst for oxidative coupling of phenols and naphthols

A novel magnetic methylene-based mesoporous organosilica composite-supported IL/Pd complex (Fe₃O₄@MePMO-IL/Pd) was synthesized and characterized, and its catalytic performance was investigated. The preparation of the Fe₃O₄@MePMO composite was achieved through coating of Fe₃O₄ nanoparticles with a mixture of tetramethoxysilane, bis(triethoxysilyl)methane, and (3-chloropropyl)-trimethoxysilane in the presence of cetyltrimethylammonium bromide surfactant. The Fe₃O₄@MePMO was then modified with alkyl imidazolium ionic liquid and palladium species to deliver the Fe₃O₄@MePMO-IL/Pd nanocatalyst. This catalyst was characterized using Fourier transform infrared, thermal gravimetric, wide-angle powder X-ray diffraction, low-angle powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometer, energy-dispersive X-ray, and nitrogen adsorption–desorption analyses. The Fe₃O₄@MePMO-IL/Pd was effectively used as a highly recoverable and durable catalyst for the selective oxidative coupling of phenols and 2-naphthols under aerobic conditions.     

Cyclization reactions of 3-hydrazino[1, 2, 4]triazino[5, 6-b]indole

The reaction of 3-hydrazino[1, 2, 4]triazino[5, 6-b]indole I with nitrous acid affords the azide III which could be cyclized with acetic anhydride to 10-acetyl-10H-tetrazolo[5′,1′:3, 4][1, 2, 4]triazino[5, 6-b]indole IIb . Cyclization reactions of I with acetic anhydride, ethyl chloroformate, carbon disulphide and aromatic aldehydes to the corresponding fused triazolo derivatives V–VIII are reported. On the other hand cyclization reactions of I with malononitrile, ethyl cyanoacetate, ethyl acetoacetate and acetylacetone to the corresponding condensed pyrazolino derivatives IX–XI are also reported. The reaction of I with α-dicarbonyl compounds to form mono and dihydrazones are reported. The structure of the compounds prepared and their cyclization mechanisms are reported.     

Time‐of‐flight secondary ion mass spectrometry and gas chromatography–mass spectrometry studies of alkanethiol self‐assembled monolayers on nanoporous gold surfaces

The dimerization of alkanethiol mixtures (hexanethiol, octanethiol, and dodecanethiol) to form self‐assembled monolayers (SAMs) from headspace on nanoporous gold surfaces was studied for the first time using gas chromatography (GC/MS) and time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS). The nanoporous gold surfaces were obtained by an acidic etching of a 585‐gold alloy. Field emission scanning electron microscopy (FE‐SEM) was utilized to study the change of the surface geometry and porosity of the gold surfaces before and after etching. Alkanethiols were deposited from the vapor phase above the thiol solutions (headspace) on nanoporous gold plates and nanoporous gold solid‐phase vmicroextraction (SPME) fibers. The nanoporous gold substrates were analyzed by TOF‐SIMS and GC/MS, respectively. The TOF‐SIMS spectra exhibited various gold–sulfur ion clusters and specific peaks related to the adsorption of thiols such as deprotonated monomers, thiolate–Au, dimers (e.g., dialkyl sulfides–Au and dialkyl disulfides–Au). The GC/MS analysis of headspace extractions of alkanethiol mixtures by nanoporous gold SPME fibers showed a high extraction efficiency of alkanethiol, dialkyl sulfide, and dialkyl disulfide when compared with the commercial SPME fibers (DVB‐CAR‐PDMS and CAR‐PDMS). Different GC/MS optimization factors were studied including the extraction time and desorption temperature.     

Dielectric spectroscopy of some heteronuclear amino alcohol complexes

The temperature dependent dielectric spectroscopic properties of two heteronuclear complexes of monoethanolamine (MEA) at a wide temperature range (303-413 K) were investigated by impedance spectroscopy, in the frequency range from 100 Hz to 100 kHz. The frequency dependence of the impedance spectra plotted in the complex plane shows semi-circles. The Cole-Cole diagrams have been used to determine the molecular relaxation time, tau. The temperature dependence of tau is expressed by thermally activated process. Relaxation frequencies corresponding to the rotation of the molecules about their long axes are expected to lie above 10 MHz and exhibit Arrhenius behavior, where a single slope is observed with activation energy values equal to 0.67 and 0.78 eV. The ac conductivity sigma(ac) (omega) is found to vary as omega(s) with the index s相似文献   

On the Reaction between 1-Aza-1,3-dienes and Push-Pull Olefins of the Acyloxymethylidene-malononitrile Type

 The reaction between push-pull olefins of the acyloxymethylidene-malononitrile type and α, β-unsaturated hydrazones affords selectively 5-alkyl-2-cyano-6-(N′,N′-dimethylhydrazono)-hexa-2,4-dienenitriles. No [4+2]-cycloaddition products were detected. The structure elucidation of the obtained compounds and possible reaction mechanisms are discussed.     

Potassium Tellurocyanate Mediated Coupling Reactions of N-(1-Chloroethylidene)Arylamines

Abstract

The reaction of potassium tellurocyanate (prepared in situ) with N-(1-chloroethylidene)arylamines (i.e., 4-RC₆H₄N = C(CH₃)Cl, where R = H, Cl, CH₃ and NO₂) in DMSO solution gave unexpectedly, after hydrolysis, the corresponding N-(3-(arylamino)butan-2-ylidene)arylamines in 63–78%. Reaction of N-(3-(arylamino)butan-2-ylidene)arylamines with SOCl₂ or with Br₂ resulted in the substitution of a halogen on the aromatic rings. The presence of a water molecule within the structure of the synthesized diimines was rationalized theoretically by Density Functional Theory (DFT). All compounds were characterized by elemental analysis, IR, NMR and mass spectroscopic data.     

5-Benzyl-1H-tetrazols from the reaction of 1-aryl-5-methyl-1H-tetrazoles with 1,2-dehydrobenzene

A series of 1-aryl-5-benzyl-1H-tetrazoles has been obtained during the reaction of 1-aryl-5-methyl-1H-tetrazoles with 1,2-dehydrobenzene. The mechanism of product formation was investigated.     

Facile One Pot Microwave Assisted Solvent‐Free Synthesis of Novel Spiro‐Fused Pyran Derivatives via the Three‐Component Condensation of Ninhydrin with Malononitrile and Active Methylene Compounds

Three‐component condensation of ninhydrin, malononitrile, and some nucleophilic reagents in the presence of piperidine under microwave irradiation without solvent afforded the corresponding spiro‐fused pyran derivatives. The structures of the products were proved by elemental analyses, IR, ¹H NMR and MS spectroscopy.