Journal of Applied Chemical Research
Volume:11 Issue: 2, Spring 2017

A convenient and efficient three-component reaction to a one-pot synthesis of thiophene derivatives from activated acetylenic compounds and ethyl chloroacetoacetate in the presence of tetramethyl thiourea in water lead to the formation of thiophenes in good yields.

First, Schiff base iminopyridine ligands has been prepared by the condensation between primary amines, different substituted anilines and active carbonyl group of pyridine carboxaldehyde, then the complexes [diiodo (3-ethylphenyl) pyridine-2-yl methylene amine] mercury(II), complex a, [dibromo (2,5-dimethylphenyl) pyridine-2-yl methylene amine] mercury(II) complex b,and [dinitrato bis-(2,6-dimethylphenyl) pyridine-2-yl methylene amine] mercury(II) nitrate, complex c, synthesized in methanol solution. The ligands and metal complexes have been characterized by elemental analysis, UV, IR, 1H-NMR and 13C-NMR spectroscopy. The spectroscopic data of metal complexes indicated that the metal ions are complexed with azomethine group and pyridine nitrogen atoms. The Schiff base ligand acts as bidentate with two N sites and can coordinate with mercury ion.

In this article, the optimized geometry, IR and UV spectra, frontier orbital analysis, natural bond orbital (NBO) analyses, and thermodynamic parameters of pomalidomide were investigated. The calculated structural parameters and stretching frequencies values are compared with experimental values of the investigated compound. Also, the relations of the thermodynamic functions vs. temperatures were fitted by quadratic formulas.

Two simple, specific, accurate, precise, sensitive and cost effective spectrophotometric methods have been developed and validated for quantification of linagliptin in pure form and pharmaceutical formulations. Method A is established on the computation of absorbance of purple coloured chromogen complex at 463 nm which is formed by the condensation reaction of the primary amine group of linagliptin with vanillin (Schiff base formation). Method B is established on computation of absorbance of orange coloured chromogen at 454 nm which is formed by the condensation reaction of the primary amino group of linagliptin with NQS (1,2-naphtho quinine 4- sulphonic acid sodium salt) reagent. Two methods executed linearity in the concentration range of 2.5-20 µg/ml and 10-90 µg/ml for method A and B respectively. Linear relationship with good correlation coefficients of 0.998 and 0.995 were monitored between absorbance and corresponding concentrations of linagliptin in vanillin and NQS respectively. The limit of detection, limit of quantification, molar absorptivity, sandell’s sensitivity and ring born concentration values were determined for the two spectrophotometric methods. The contemplated methods were validated statistically as per ICH guidelines. The reliability of both the methods is further ascertained by performing recovery tests by standard addition method. No significant interference was inspected from the excipients commonly used as pharmaceutical aids with the assay procedure. The contemplated methods were simple, sensitive, specific and can be successfully employed in routine analysis of linagliptin in pharmaceutical dosage forms.

Magnetic polymer particles which were modified by vinyl groups and subjected to polymerization by vinyl β-Cyclodextrin derivative, has been used as adsorbent for sorption and release of bovine serum albumin and the equilibrium and kinetics of the adsorption process were studied. The absorbability and releasing of this protein through the new polymer has been measured by ultraviolet-visible spectroscopy. Effects of various parameters such as pH, contact time and capacity for adsorption of bovine serum albumin have been studied in vitro and the optimum magnitudes were 4, 37.94 mg/g and 5 minutes respectively. The experimental results show that the adsorption of Bovine serum albumin on magnetic particles was affected greatly by the pH andthe adsorption equilibrium isotherm was fitted well by the Freundlich model. Bovine serum albumin was released from magnetic particles in simulated intestinal fluids. It was released up to about 7 h at high speed and then it released slowly up to 30 h.

An easy and fast pathway in preparation of organo-functionalized silica in nanosize range with phenyl-terminated group via co-condensation method is reported. Fourier transform infrared (FTIR) spectra confirmed the grafting process and scanning electron microscopy (SEM) image corroborated formation of nanosized material. Applicability of phenyl-modified nanosilica was examined as a sorbent in dispersive solid phase extraction (DSPE)of triazine herbicides. The effect of the different parameters affecting DSPE efficiency, such as sample pH, extraction time was studied. The amount of enrichment factors for triazines using proposed method were found in the range of 31-43. Calibration curves of triazines showed linearity in the range of 0.5 200, 1.0-200, 1.5-200 and 2.0-1000 µg L-1 for analytes. In addition, the detection limits for the analytes were in the range of 0.2-0.6 µg L-1. The values of relative standard deviation (RSD%) for n=3 at the concentration level of 10 µg L-1 were obtained lower than 3.5% for all analytes. The proposed method was also applied to the extraction of triazine herbicides from environmental samples and satisfactory relative recoveries were obtained.

Reactions of N-isocyaniminotriphenylphosphorane with α- chloroketones in the presence of aromatic carboxylic acids proceed smoothly at room temperature and in neutral conditions to afford new disubstituted 1,3,4-oxadiazole derivatives in high yields.

An environmental friendly synthetic route for copper (II) chloride dihydrate catalyzed one pot multicomponent synthesis of biologically active high substituted dihydro-2-oxypyrroles has developed. The non-toxic, low-cost catalyst and eco-friendly and good to high yields are the notable benefits for the efficient synthesis of these products.