Muhammad Danish

PALLADIUM CATALYZED HECK-MIZOROKI AND SUZUKI-MIYAURA COUPLING REACTIONS (REVIEW)

This article is about the progress of palladium compounds as a catalyst for Heck-Mizoroki and Suzuki-Miyaura coupling reactions. Industrial catalysts with broad applicability need continuous catalyst development process through modification of ligand design, geometry and functionality. Recently catalysts have been synthesized through attachment of the activated palladium complexes on the surface of polymer support, particularly, insoluble in reaction medium. An appropriate mixture of palladium salt and ligand is also used as an important modification in some cases to get better results. We surveyed the important palladium compounds synthesized up to early 2014 for Heck-Mizoroki and Suzuki-Miyaura coupling reactions and summarize their progress in terms of ligand modification and other associated parameters.

Thermodynamic Characteristics and Spectral- Luminescent Properties of N-m-Tolylbenzamide in Microheterogeneous Surfactant Self-Assemblies

To model the binding to biomembranes, the interactions of potent N-m-tolylbenzamide (NTB) with a cationic surfactant, cetyltrimethylammonium bromide (CTAB) and an anionic surfactant, sodium dodecyl sulfate (SDS), have been investigated. The study was carried out by quantifying the absorption and fluorescence emission spectra of NTB as a function of pre-micellar to post-micellar surfactant concentrations in the temperature range of 25–50xa0°C. NTB is a strongly fluorescent compound that exhibits intense violet fluorescence. Using mathematical models, the water–micelle partition coefficient (Kx), surfactant–NTB binding constant (Kb), binding capacity (nb) and the degree of counter-ion binding (α) are discussed from the thermodynamic viewpoint, considering the thermodynamic parameters of additive solubilization (

Simultaneous estimation of rosuvastatin and amlodipine in pharmaceutical formulations using stability indicating HPLC method

Delta G_{text{p}}^{^circ } ,,Delta H_{text{p}}^{^circ } ,,Delta S_{text{p}}^{^circ }

Development of Mixed metal Metal-organic polyhedra networks, colloids, and MOFs and their Pharmacokinetic applications

ΔGp∘,ΔHp∘,ΔSp∘). The high values of all interactions, especially when the surface charge of the organized medium is cationic, ensure that there are greater interactions between the NTB and CTAB than with SDS. The NTB molecule is found to be located at only one binding site of each surfactant and probably exhibits static quenching rather than a collisional quenching mechanism. These findings have been confirmed by the binding capacity for the NTB–surfactant combinational system and Stern–Volmer quenching constant (Ksv) values. The observed depression in binding strength of the counterions with temperature increase favors the promising solubilization of NTB in the palisade layer of micelles leading to penetration binding.

Cuscuta reflexa and Carthamus Oxyacantha: potent sources of alternative and complimentary drug

Abstract A viable cost-effective and isocratic approach employing C-18 column (250 mm × 4.6 mm, 5 μm) based HPLC has been utilized to separate and estimate the drug, tranexamic acid in pharmaceutical formulations. Tranexamic acid contains no π-electrons to act as fluorophore or chromophore hence pre-column derivatization was performed with benzene sulfonyl chloride in aqueous medium at room temperature. The derivatized drug was then estimated using C-18 column by exploiting a 25:75 (v/v) solvent mixture of acetonitrile and 0.1 M ammonium acetate (pH 5.0) as the mobile phase. The flow rate of mobile phase was 1 mL/min and detection was performed at a wavelength of 232 nm using UV detector. Retention time of tranexamic acid was 4.42 min. The method followed linear regression equation in the concentration range of 1–100 μg/mL with co-efficient of determination equal to 0.9994. The limit of detection and limit of quantitation were 0.3 and 1 μg/mL, respectively. The relative standard deviation and recovery ranges for tranexamic acid were found to be 0.11–2.47% and 97.60–103.25%, respectively. The suggested method is very sensitive and may have the potential to be used for tranexamic acid detection in medicinal formulations.

4-[(4-Meth­oxy­benzene­sulfonamido)­meth­yl]cyclo­hexane-1-carb­oxy­lic acid

A viable cost-effective and isocratic approach employing C-18 column (250 mm × 4.6 mm, 5 µm) based HPLC has been utilized to separate and estimate the drugs, rosuvastatin, amlodipine and their stress induced degradation products, simultaneously in pharmaceutical formulations. Focused on ICH guideline parameters, the efficient separation of both drugs and their degradation products was achieved by optimizing a 30:70 (v/v) solvent mixture of acetonitrile and 0.1 M ammonium acetate buffer (pH 5) as mobile phase. The flow rate of the mobile phase was 1.5 mL/min and all the detections were carried out at 240 nm using UV detector. The method was linear in the concentration range of 1-200 µg/mL for rosuvastatin with 0.996 coefficient of determination value. For amlodipine, linearity was in the range of 0.5-100 µg/ml with 0.994 coefficient of determination value. Both the drugs along with their degradation products were separated in less than twenty minutes. The results of within-day and between-day precision were varied from 0.72 to 1.81% for rosuvastatin and 0.83 to 1.88% for amlodipine. The results show that this ICH validated method can be employed successfully for the routine as well as stability quantification of both the active ingredients simultaneously in pharmaceutical formulations.

Tetra­aqua­bis­[2-(2-nitro­phen­yl)acetato-κO]cobalt(II)

In the crystal structure of the title compound, C11H15NO4S, two independent molecules are present per asymmetric unit; they are dimerized through O—H⋯O hydrogen bonds between their carboxy groups to generate R 2 2(8) loops. An intramolecular N—H⋯O link in one of the molecules closes an S(5) ring. The dimers are linked by N—H⋯O and C—H⋯O hydrogen bonds to form a three-dimensional network. The C atoms of the isopropyl group of one of the molecules are disordered over two orientations in a 3:1 ratio.

Viscoelastic and adhesive properties of polystyrene-hydrogenated (3,4-polyisoprene and 1,4-polyisoprene)-polystyrene and polymethyl methacrylate-polybutyl acrylate-polymethyl methacrylate-based HMPSA

SummaryThe coordination networking of discrete metal-organic polyhedra (MOPs) involving different ligands as well as metals is a challenging task due to the features of limited solubility and chemical stability of these polyhedra. An unusual approach, ligand-oriented polyhedral networking via click chemistry and further metal coordination is reported here. An alkyne decorated Cu(II)-MOP self-catalyzes the regioselective click reaction (1,3-dipolar cycloaddition) using azide-functionalized ligands under unconventional reaction conditions. Introducing new metal ions, M(II), interlinks the carboxylic groups on the MOP surfaces creating coordination networks. On the other hand, exposure of the respective individual ligand components in the presence of Cu(II) promotes an in-situ click reaction along with metal coordination generating a new 3D-framework. These materials demonstrated a high drug hosting potential exhibiting a controlled progressive release of anticancer (5-flourouracil) and stimulant (caffeine) drugs in physiological saline at 37u2009°C. These innovative and unconventional MOP networks provide a significant conceptual advance in understanding.