No abstract

In this work, an efficient and new Fe3O4@APTES@isatin-SO3Hwas synthesized through immobilization of isatin sulfonic acid on silica modified Fe3O4 nanoparticles. The synthesizedFe3O4@APTES@isatin-SO3Hmagnetic nanoparticles (MNPs) were characterized using the energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), X-ray diffraction (XRD), and thermogravimetric(TGA) analysis. The Fe3O4@APTES@isatin-SO3HMNPs performed efficient catalytic activity as a magnetically recyclable heterogeneous catalyst for one-pot, condensation reaction of 1,2-dicarbonyl compounds and o-phenylen diamines in ethanol at room temperature to afford quinoxaline derivatives.

Due to the wide importance of β-phosphorylated ketones as key building-blocks in the fabrication of various pharmaceutically active organophosphorus compounds, finding new and truly efficient methods for their preparation.

Ascorbic acid is a water-soluble vitamin essential in human nutrition, an antioxidant, a scavenger of free radicals in biological systems, and a cofactor of several enzymes. The reference range for ascorbic acid in healthy people is 6 - 20 mg L-1. The variable concentration of ascorbic acid within biology fluids was found in clinical investigations to be a metric for assessing the exact amount of oxidative stress in the body's metabolism. Electroanalytical techniques are a group of methods in analytical chemistry, especially with extensive application in pharmaceutical industries. These techniques attracted further attention due to their unique characteristics, such as reduced sample or solvent con­sumption, high analysis speed, low operating cost, and high sensitivity, which made them suitable candidates for replacement or supplementation for spectrophotometry and separation approaches. The purpose of this article is to scrutinize the mechanisms and applications of current electroanalytical methods, including amperometric techniques, square wave voltammetry, differential pulse voltammetry and cyclic voltammetry, in their applications in pharmaceutical analysis for the detection of ascorbic acid. Related examples have been cited in the form of selected studies.

No abstract

Addition of an isocyanide to an iminium ion intermediate that forms from the reaction between a heteroarylcarbaldehyde and a secondary amine leads to formation of sterically congested 2-(heteroaryl)acetamide derivatives in the presence of silica gel at room temperature. The structures of the products were deduced from their 1 H NMR, 13 C NMR, and infrared spectra and mass spectrometry.

The use of Smiles rearrangement in Ugi-type couplings with tropolone allows very straightforward multicomponent formation of 2-(N,N-dialkylamino)-2,4,6-cycloheptatrien-1-one derivatives. The Ugi four-component reaction of isocyanides with tropolone (2-hydroxy-2,4,6-cycloheptatrien-1-one), primary amines and aldehydes proceeds smoothly and cleanly under mild conditions to afford 2-(N,N-dialkylamino)-2,4,6-cycloheptatrien-1-one derivatives in fairly good yields.

The reaction of (E)‐3‐aryl‐2‐propenoic acid derivatives with (N‐isocyanimino) triphenylphosphorane proceeds smoothly at room temperature to afford the corresponding 2‐[(E)‐2‐aryl‐1‐ethenyl]‐1,3,4‐oxadiazole via an intramolecular aza‐Wittig reaction in good yields under neutral conditions. The structures of the products were deduced from their IR, 1H NMR, and 13C NMR spectra and mass spectrometry. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:612–616, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20701