Chemical Methodologies
Volume:4 Issue: 5, Sep-Oct 2020

Fe3O4bonded pyridinium-3-carboxylic acid-N-sulfonic acid chloride, as a magnetic and reusable catalyst, was reported for the one-pot multi-component synthesis of some 3,4-dihydropyrimidin-2(1H)-ones by the reaction of urea, ethyl acetoacetateand various aldehyde under solvent-free conditions. The products were identified by FT-IR, 1H NMR and 13C NMR spectra and the catalyst was reused successfully for three times.

Trifluoromethylated and ring-fluorinated 4H-chromones have been prepared via cyclodehydration and via the baker-venkataraman rearrangement.  The cyclodehydration of 4,4,4-trifluoro-1-(1-naphthol-2-yl)-1,3-butanedione was performed under a variety of base promoted and acid catalyzed processes enroute to 2-trifluoromethyl-β-naphthochromone. Using microwave irradiative, sonication and conventional processes, selected o-hydroxyaromatic ketones underwent single-pot, based promoted baker-venkataraman rearrangements with trifluoroacetic anhydride to give trifluoromethylated 4H-chromones in yields ranging from 50-82%. Microwave irradiation conditions allowed for yields ranging from 50-80%, which compare favorably to yields achieved via conventional methods (60-82%) as well as reducing reaction times by 55% compared to conventional refluxing conditions.

In this research study, an efficient approach is reported for the solvent-free synthesis of various chromene derivatives catalyzed by alumina-supported cobalt nanoparticles in high yields. Alumina-supported cobalt nanoparticles (Co/Al2O3 nanocatalyst), efficiently catalyzed the reaction between the resorcinol or 2-hydroxy naphthalene with benzaldehyde and malononitrile into chromene derivatives in high efficiency. This procedure allowed us to obtain corresponding products in short reaction times, simple work-up, and high yields. Experimental procedure with Co/Al2O3 nanocatalyst is very simple and the catalyst is easily removed by filtration. The catalyst was also found to be recyclable and can catalyze synthesis of the chromenes up to 5 times well.

Nettle (Urtica dioica L.) is one of the most well-known medicinal plants. It has been mostly used for medical purposes. This study summarizes extensive results on the antimicrobial effect of Urtica dioica L. The aim of this study was to investigate several extraction methods of nettle extract for more access to flavonoid materials especially quercetin. For this purpose, three methods (soaking, sonication, soxhlet) and three solvents (chloroform, methanol, deionized water) were used for extraction. Finally, the highest amount of quercetin determined by HPLC was sonication for 90 min with methanol solvent. The effect of this extract was investigated on several pathogenic microbes including Escherichia coli, Entrecoccus faecalis, Klebsiella pneumoniae, Acinetobacter calcoaceticus, Candida albicans. Antibiogram testing revealed that Escherichia coli and Candida albicans were resistant to nettle extract, Acinetobacter calcoaceticus and Klebsiella pneumonia, were sensitive and Enterococcus faecalis was semi-susceptible.

In this research study, relative stability of all the tautomers of phthalazinone ring in the gas phase and the solvent effect on the tautomeric equilibrium were evaluated using the density functional theory-polarizable continuum model at the B3LYP/6-311++G(d,p) basis set. In addition, variation of the dipole moments in the gas phase and solution, the specific solvent effect on the transition state of proton transfer assisted by a water molecule and the NBO calculated charges on the atoms were investigated. The water-assisted tautomerization with one molecule revealed that, the free energy activation barrier was reduced compared to those for the uncatalyzed systems. In the all the tautomers of phthalazinone rings, when going from gas phase to more polar solvents, the net charges on the O atoms slightly increased.

Due to the great number of medicinal application of morphine in drugs, the morphonium chloride (IL01) and morphonium nitrous (IL02) were investigated using the computational method to assess their biological activity. The quantitative structure activity relationship (QSAR) parameters for instance, charge density, surface area grid, volume, LogP, polarizability, refractivity, and molecular mass were demonstrated through the density functional theory (DFT) for simulation as well as the chemical reactivity like HOMO, LUMO, and HOMO, LUMO gap were also calculated. In addition, the most important thermodynamic properties such as entropy and heat of capacity were calculated using DFT method. The values of the initial entropy and heat of capacity were zero without applying temperature. At 273 K, the entropy and heat of the capacity are 0.117, 0.113, and 0.062, 0.055 kcal/mol-deg for IL01 and IL02, respectively, which finally increased by 0.177, 0.162 and 0.120, 0.099 kcal/mol-deg at 523 K. When electric field was applied on IL01, and IL02, the entropy was decreased by 32.47% and 2.65% whereas the heat of capacity was decreased by 79.03% and 1.81%, respectively. Finally, in same electric field with increasing temperature, the entropy was enhanced by 16.45% and 45.45% besides the heat of capacity was increased about 100% at 523 K and IL02 was found to be less response compared with that of the IL01 at low temperature for electric filed but almost similar response at high temperature.

This research study aimed at developing and validating a simple, precise, accurate, specific and economical spectrophotometric method for simultaneous estimation of Ranolazine (RANO) and Metformin hydrochloride (MET) in synthetic mixture. This method is based on first order derivative spectroscopy.Ranolazine and Metformin hydrochloride exhibited absorbance at working wavelength 232.86 nm (Zero crossing point of Metformin hydrochloride) and 249.29 nm (zero crossing point of Ranolazine) respectively using water as a diluent. This method was validated as per ICH guideline. Linearity was established over the concentration range of 2-35 μg/mL both of Ranolazine and Metformin hydrochloride with correlation coefficients 0.999 and 0.998, respectively. Accuracy was obtained between 98.48-101.85% and 98.25-100.88% for Ranolazine and Metformin hydrochloride respectively. LOD and LOQ were found to be 0.08 μg/mL and 0.25 μg/mL for Ranolazine and 0.25 μg/mL and 0.77 μg/mL for Metformin hydrochloride, respectively.The results revealed that, the developed method was suitable for the routine analysis of determination of Ranolazine and Metformin hydrochloride in combine dosage form. Keywords: Ranolazine; Metformin hydrochloride; First order derivative; UV spectrophotometry; ICH guideline

In this study, condensation reaction of the aldehydes with various ketones in the presence of sulfonic acid functionalized pyridinium chloride [pyridine–SO3H]Cl as an ionic liquid and catalyst were carried out to prepare the α,αʹ- bis(arylidene)cycloalkanone under the solvent free conditions. The purity and yield of the products were high and their identification was performed by the spectroscopic analysis and comparison of the physical information with known compounds in the previous literature.

In this research study, acidic ionic liquid based silica-coated Fe3O4 nanoparticles [Fe3O4@SiO2@(CH2)3-Py]HSO4as an efficient and reusable magnetic nanocatalyst was synthesized and characterized using the FT-IR, TEM, VSM, XRD, and TGA analysis. The catalytic performance of the [Fe3O4@SiO2@(CH2)3-Py]HSO4was evaluated towards the regioselective thiocyanation of aromatic and heteroaromatic compounds with KSCN as a thiocyanate source afforded the corresponding aryl and heteroaryl thiocyanates derivatives 2a-n at room temperature in H2O2 as a clean oxidant and ethanol as a green solvent. A broad range of products 2a-n was synthesized high yields (up to yield 97%) under the mild reaction conditions.

An unusual work is that the galvanic cell described is non-standard and has irreversible electrodes. Non-standard are comparative electrodes too. Only 1 electrochemical cell Al | NaOH (it is polarizer, amperage-forming or polarizing agent). By measuring the amperage generated by this electrochemical cell, the dissolution rate of aluminum was investigated. Inhibition of aluminum dissolution was supposed to be achieved for the first time using the “Dorogov antiseptic stimulator of fraction No. 2” or ASD-2F, acceleration by the introduction of a depolarizer (it is depolarizing or amperage-absorbing agent) consisting of steel and copper cores protected from vortex flows caused by anything. The amperage and voltage characteristics “amperage on polarizer + depolarizer--voltage on depolarizer” were built. The fastest dissolution occurs when a larger voltage accounts for a larger voltage. A correlation was revealed "the ionic strength of the inhibitor at the N and O atoms of 2nd...5th groups of "organic-part" of ASD-2F IΣ2 ....5 amperage of a galvanic cell for 600 mV", and a correlation was revealed "donor and acceptor strength of molecules of 2nd - 5th groups of "organic-part" of ASD-2F HΣ2...5 amperage of a galvanic cell for 600 mV». It is very important that each line of each diagram is analyzed individually.

In this research study, a green protocol for facile and eco-safe synthesis of 12-aryl-tetrahydrobenzo[α]xanthene-11-ones, 1,8-dioxo-octahydroxanthenes and 14-aryl-14H-dibenzo[α,j]xanthenes using salicylic acid as a bio-based and natural Brønsted acid catalyst in a one-pot, multi-component synthesis under solvent-free conditions is reported. The present methodology is an environmentally friendly approach for the synthesis of various xanthene derivatives. It also offers several merits including, good yields, short reaction times, efficient, eco-friendly, solvent-free conditions, and materials available

In this work, D-optimal mixture design was applied as an experimental design to screen and optimize the effect of the composition of a carbon paste on its performance. In this study, chitosan was offered as a ligand for the determination of La(III) with the carbon paste electrode. In the fabricated sensor, the greatest nernstian slope was achieved on the optimized mixture composition by experimental design: 60.00% w/w powder graphite, 1.53% w/w multi-walled carbon nanotubes (MWCNTs), 29.79% w/w paraffin oil, and 8.68% w/w chitosan. MWCNT was used for increasing the electrode response to La(III). The quadratic fitting pattern based on D-optimal model was used to find the desirability functions of the suggested design to assess the cross-interferences and the interactions between the factors. The fabricated sensor for determining the La(III) ions demonstrated a maximum nernstian slope equal to 19.70 mV.decade-1 along a linear range from 1.0×10−6 to 1.0×10−2 mol/L−1 and detection limit of 10−6 mol/L-1. The designed sensor was successfully tested in the pH range of 2-9 with suitable selectivity, fast response time (about 30 s) and long lifetime (over 2 months) was obtained without any deviation. The offered electrode was used successfully as an indicator in the potentiometric titration of La(III) with EDTA.