A three-component cyclocondensation reaction for the synthesis of new triazolo[1,5-a]pyrimidine scaffolds using 3-aminotriazole,aldehydes and ketene N,S-acetal

Molecular Diversity - This study describes the use of 3-aminotriazole, different aldehydes and N-methyl-1-(methylthio)-2-nitroethenamine as a ketene N,S-acetal in a three-component condensation for...     

Pd(0)-guanidine@MCM-41: a very effective catalyst for rapid production of bis (pyrazolyl)methanes

In this research, a rapid, green and efficient protocol for synthesis of bis (pyrazolyl)methane derivatives in the presence of Pd(0)-guanidine@MCM-41 catalysts under solvent-free conditions by the following two methods has been reported: (i) via the one-pot pseudo five-component reaction among phenylhydrazine (2 equivalents), ethyl acetoacetate (2 equivalents) and aromatic aldehydes (1 equivalent); and (ii) the one-pot pseudo three-component reaction between 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one (2 equivalents) and aromatic aldehydes (1 equivalent). Some advantages of this protocol include: green conditions, extremely short times, high efficiency, proper one-pot operation, generality of method, easy work-up and recyclability, and reusability of the catalyst up to five times without significant loss in catalytic activity.     

Capable Lie algebras with the derived subalgebra of dimension 2 over an arbitrary field

In this paper, we classify all capable nilpotent Lie algebras with the derived subalgebra of dimension 2 over an arbitrary field. Moreover, the explicit structure of such Lie algebras of class 3 is given.     

Yttrium(III) Nitrate: A Powerful Catalyst for Green and Rapid Synthesis of Some Supramolecules

A convenient and rapid procedure for the synthesis of calix[4]resorcinarenes as useful supramolecules has been developed via a reaction of aryl aldehydes with resorcinol in the presence of yttrium(III) nitrate under solvent‐free conditions. This eco‐friendly method has many appealing attributes such as excellent yields, short reactions times, and simple work‐up procedures.     

Synthesis of Novel and Thermally Stable Water Insoluble Coumarin‐based Azo Dyes via a Mild and Green Procedure

A series of novel azo coumarin dyes were synthesized by the diazotization of 7‐amino coumarins in the presence of catalytic amounts of tungstate sulfuric acid (TSA) followed by coupling with phenol derivatives. Tungstate sulfuric acid catalyzes this reaction at room temperature and short reaction time with high yields.     

Computational mechanistic investigation of the gas phase C2H4 + CO reaction on the singlet and triplet potential energy surfaces

Reaction pathways of ethylene and carbon monoxide on the singlet and triplet potential energy surfaces (PESs) have been calculated at B3LYP/6-311++G (3df, 3dp), G3B3 and CCSD(T)//B3LYP levels. Reaction mechanisms have been investigated by analysis of various structures. Suggested reaction mechanisms reveal that ³P3(CH₂CHCHO) and ³P4(CH₃CCHO) are thermodynamically stable adducts with the negative value in Gibbs free energies on the triplet PES. In addition, results show that one intersystem crossing exists between triplet and singlet PESs, which are obtained by scanning of the C–C bond length in ¹IN3 and ³IN7 species.     

ALANINE/CHLOROCHROMIC ACID/SILICA GEL: AN EFFICIENT AND SELECTIVE REAGENT FOR THE OXIDATION OF ORGANIC FUNCTIONAL GROUPS

Alanine/chlorochromic acid/silica gel is a new and selective reagent for the efficient oxidation of sulfides, thiols, oximes, and alcohols. Oxidation of sulfides is solvent dependent. In chloroform at room temperature sulfoxides are formed as the major products, while in carbon tetrachloride or under solvent-free conditions solfones are produced in good-to-excellent yields.     

A Hexagonally Ordered Nanoporous Silica-Based Fiber Coating for SPME of Polycyclic Aromatic Hydrocarbons from Water Followed by GC–MS

A highly porous fiber coating material was prepared and functionalized with 3-amino propyl triethoxysilane (APTES) on hexagonally ordered nanoporous silica (SBA-15). Applicability of this coating was assessed employing a laboratory made solid-phase microextraction (SPME) device and gas chromatography–mass spectrometry for the simultaneous sampling and determination of trace polycyclic aromatic hydrocarbons (PAHs) from aqueous sample solutions. A one at the time optimization strategy was applied to investigate and optimize important extraction parameters such as extraction temperature, extraction time, ionic strength and sonication time. In the optimum conditions, the relative standard deviations for deionized water, spiked with selected PAHs were between 3.3 and 7.7% (n = 3), and detection limits for the studied compounds were 4.2 and 26.1 pg mL⁻¹. No significant change was observed in the extraction efficiency of the new SPME fiber, over 50 extractions. The proposed method was successfully applied to the extraction and determination of PAHs in the waste water samples.

     

An Efficient One‐Pot,Four‐Component Synthesis of {[(1H‐1,2,3‐Triazol‐4‐yl)methoxy]phenyl}‐1H‐pyrazolo[1,2‐b]phthalazine‐5,10‐dione Derivatives

The 1‐{[(1H‐1,2,3‐Triazol‐4‐yl)methoxy]phenyl}‐1H‐pyrazolo[1,2‐b]phthalazine‐5,10‐dione derivatives 5 were synthesized by a simple and efficient method, i.e., by the four‐component, one‐pot condensation reaction of phthalohydrazide 4 , a (propargyloxy)benzaldehyde 1 , an active methylene compound 3 (malononitrile or ethyl cyanoacetate), and an azide 2 in the presence of Cu(OAc)₂/sodium L ‐ascorbate as catalyst and 1‐methyl‐1H‐imidazolium trifluoroacetate ([Hmim](CF₃COO)) as an ionic‐liquid medium in good to excellent yields (Scheme 1).