Theoretical calculation of the pKa values of some drugs in aqueous solution

In this work, calculations of pK_a values have been performed on benzoic acid and its para‐substituted derivatives and some drugs by using Gaussian 98 software package. Gas‐phase energies were calculated with HF/6‐31 G** and B3LYP/6‐31 G** levels of theory. Free energies of solvation have been computed using the polarizable continuum model (PCM), conductor‐like PCM (CPCM), and the integral equation formalism‐PCM at the same levels which have been used for geometry determination in the gas‐phase. The results that show the calculated pK_a values using the B3LYP are better than those using the corresponding HF. In comparison to the other models, the results obtained indicate that the PCM model is a suitable solvation model for calculating pK_a values. For the investigated compounds, a good agreement between the experimental and the calculated pK_a values was also observed. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011     

Ultrasound-assisted synthesis of 3-(1-(2-(1H-indol-3-yl)ethyl)-2-aryl-6,6-dimethyl-4-oxo-4,5,6,7-tetrahydro-1H-indol-3-yl)indolin-2-ones by novel core-shell bio-based nanocatalyst anchoring sulfonated L-histidine on magnetized silica (SO3H-L-His@SiO2-nano Fe3O4)

An efficient synthesis of 3-(1-(2-(1H-indol-3-yl)ethyl)-2-aryl-6,6-dimethyl-4-oxo-4,5,6,7-tetrahydro-1H-indol-3-yl)indolin-2-ones is reported via a one-pot three-component reaction of 3-phenacylidenoxindoles, tryptamine, and dimedone under ultrasound irradiation using a newly prepared core-shell nanostructure. The utilized nanocatalyst is obtained by anchoring sulfonated L-histidine amino acid shell, as the bio part, on silica-nanomagnetite core (SO₃H-L-His@SiO₂-nano Fe₃O₄) and characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy (¹H NMR), field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, thermogravimetric/differential thermal analysis, vibrating sample magnetometer measurements, transmission electron microscopy, and back-titration. The protocol contains several advantages, such as relatively short reaction times, simple work-up procedure by separation of the catalyst with an external magnet, the use of economical and environmentally friendly ultrasonic waves, and reusability and recoverability of the core-shell nano-promoter for three runs without significant activity loss.     

Determination of organophosphorus pesticides by gas chromatography with mass spectrometry using a large‐volume injection technique after magnetic extraction

A fast and efficient method was developed for the extraction and determination of organophosphorus pesticides in water samples. Organophosphorus pesticides were extracted by solid‐phase extraction using magnetic multi‐walled carbon nanotubes and determined by gas chromatography with ion‐trap mass spectrometry. Parameters affecting the extraction were investigated. Under optimum conditions of the method, 10 mg magnetic multi‐walled carbon nanotubes were added into 10 mL sample. After 2 min, adsorbent particles settled at the bottom of test tube with a magnet. After removing aqueous supernatant, the analytes were desorbed with acetonitrile. Then, 70 μL of acetonitrile phase was injected into the gas chromatography and mass spectrometry system that had an ion‐trap analyzer. To achieve high sensitivity, the large‐volume‐injection technique was used with a programmed temperature vaporization inlet, and the ion‐trap mass spectrometer was operated in single ion storage mode. Under the best conditions, the enrichment factors and extraction recoveries were in the range of 113–124 and 74–103%, respectively. The limits of detection were between 3 and 15 ng/L, and the relative standard deviations were < 10%. This method was successfully used for the determination of organophosphorus pesticides in dam water, lagoon water, and river water samples with good reproducibility and recovery.     

KF/Al2O3‐Mediated N‐Alkylation of Amines and Nitrogen Heterocycles and S‐Alkylation of Thiols

KF/Al₂O₃ efficiently catalyzes N‐alkylation of heterocyclic, primary, and secondary amines and S‐alkylation of thiols with a variety of alkyl halides. The N‐alkylation and S‐alkylation adducts were produced in good to excellent yields and in short times.     

Selective Sensing Characteristics of Ca Doped BeO Nano-sized Tube toward H20 and NH3

By means of density functional calculations, the structural and electronic properties of chemical modification of pristine and Ca-doped BeO nanotubes were investigated with NH3 and H20 molecules. It was found that the NH3 and H20 molecules can be adsorbed on the Be atom of the tube sidewall with the adsorption energies of about 36.1 and 39.0 kcal/mol, respectively. Density of states analysis shows that the electronic properties of the BeONT are slightly changed after the adsorption processes. Substitution of a Be atom in the tube surface with a Ca atom increases the adsorption energies by about 7.4 and 14.7 kcal/mol for NH3 and H20, respectively. Unlike the pristine tube, the electronic properties of Ca-doped BeONT are sensitive to NH3 and H20 molecules. Also, the Ca-doped tube is much more sensitive to H20 molecule than NH3 one.     

Determination of Chlorpromazine Hydrochloride with a Layered Double Hydroxide Modified Glassy Carbon Electrode as a Nanocatalyst

We report a simple and sensitive voltammetric sensor for the determination of chlorpromazine (CPZ) based on Ni?Al layered double hydroxide (NiAlLDH) modified glassy carbon electrode (GCE). NiAlLDH was simply electrodeposited on GCE surface in a very short time. The response linear range was 1×10^?3–1×10^?9 mol L^?1, with a detection limit of 1×10^?9 mol L^?1. The NiAlLDH film showed well defined and well separate peaks for dopamine, ascorbic acid, uric acid and CPZ in the same solution. The proposed electrode was used to measure the active pharmaceutical ingredient of CPZ tablet as a real sample.     

Polystyrene@graphene oxide-Fe3O4 as a novel and magnetically recyclable nanocatalyst for the efficient multi-component synthesis of spiro indene derivatives

Research on Chemical Intermediates - Polystyrene (PS)-coated magnetic graphene oxide (GO-Fe3O4) nanocomposite has been prepared and characterized by FT-IR, TEM and VSM techniques, and its catalytic...     

A Novel Copper Oxide Nanoparticle Conjugated by Thiosemicarbazone Promote Apoptosis in Human Breast Cancer Cell Line

The current study highlights the apoptotic activity of copper oxide (CuO) nanoparticles functionalized by Glutamic acid and conjugated by thiosemicarbazone (TSC) toward human breast cancer (MCF-7) and normal (HEK293) cell lines. To this aim, the co-precipitation method was used for preparation the CuO nanoparticles. Afterward, the CuO nanoparticles functionalized by glutamic acid. After that the functionalized copper oxide nanoparticles (CuO@Glu) conjugated to thiosemicarbazone. In next step, the final nanoparticle product (CuO@Glu/TSC) was characterized by physico-chemical techniques including Fourier transform infrared (FT-IR) spectroscopy, Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Energy dispersive X-ray analysis (EDX), zeta potential analysis and dynamic light scattering (DLS). The effects of in vitro cell viability in CuO@Glu/TSC nanoparticles showed the anti-proliferative properties with a dose-dependent manner (IC₅₀?=?133.97 µg/ml). The IC₅₀ of CuO@Glu/TSC on normal cell line was 230.2 µg/ml. This IC₅₀ deference shows high cytotoxicity of CuO@Glu/TSC nanoparticles on tumor cells and low cytotoxicity on non-tumorigenic cells (HEK293) and is considered as an important aspect for this nanoparticles. Also, CuO@Glu/TSC nanoparticles had efficient effects in inhibiting the growth of breast cancer cell line (MCF-7). In addition, the CuO@Glu/TSC nanoparticle induced apoptosis symptoms which were assessed by Caspase-3 activation assay, Annexin V/ propidium iodide flow cytometry, and Hoechst 33258 staining. Further, Bax and Bcl-2 genes expression was estimated by real time PCR. The expression of Bax increased 1.69 fold, while the expression of Bcl-2 decreased 0.6 fold. The results of the current study propose that CuO@Glu/TSC nanoparticles reveal effective anti-cancer activity against breast cancer cell line.