A palladium catalyzed atom-efficient cross-coupling reactivity of triarylbismuths with α,β-unsaturated acyl chlorides

An atom-efficient cross-coupling reactivity of triarylbismuths (1 equiv) was demonstrated by cross-coupling reaction with 3 equiv of α,β-unsaturated acyl chlorides under palladium catalysis in the synthesis of a series of functionalized α, β-unsaturated ketones in high isolated yields.     

Simultaneous quantification of (E) and (Z) isomers of rilpivirine and four degradation products in bulk and tablets by reversed-phase ultra-high-performance liquid chromatography and confirmation of all by molecular weight

The (E)-isomer of rilpivirine is an approved antiretroviral drug used to treat human immunodeficiency virus. A simple, fast, accurate, and precise analytical method is required to confirm the quality, purity, efficacy, and safety of drug substances and drug products containing rilpivirine. This research article offers a comprehensive ultra-high performance liquid chromatography method for the simultaneous separation and quantification of (E) and (Z) isomers of rilpivirine, including two amide impurities, one nitrile impurity, and one dimer impurity, in both bulk and tablet forms. After complete validation, the proposed reversed-phase ultra-high-performance liquid chromatography method has proven to be simple, fast, linear, accurate, and precise, with a lower limit of quantification and detection of 0.05 and 0.03 μg/ml, respectively, for all six analytes. Separation was achieved on a Waters Acquity ethylene bridged hybrid Shield RP18 (150 × 2.1 mm, 1.7 μm) column maintained at 35.0°C using a gradient elution of acetonitrile and 0.05% formic acid in 10 mM ammonium formate at a flow rate of 0.30 ml/min. A systematic forced degradation study on the undissolved rilpivirine revealed the formation of acid-base hydrolyzed amide impurities (Impurity-A and Impurity-B), oxidative nitrile impurities (Impurity-C), and Z-isomer and dimer impurities of rilpivirine (Impurity-D and Impurity-E) due to alkaline hydrolysis and photodegradation. The proposed method is primarily appropriate for applications requiring the precise determination of desired and undesired isomers of rilpivirine and its degradation products, such as those involving the safety, efficacy, and quality roles of rilpivirine in bulk and tablet forms. Additionally, the proposed ultra-high-performance liquid chromatography method in combination with a mass spectrometer and photo-diode array detector is helpful for the confirmation and correct identification of all analytes.     

Modified-Hydroxyapatite-Chitosan Hybrid Composite Interfacial Coating on 3D Polymeric Scaffolds for Bone Tissue Engineering

Three dimensional (3D) scaffolds have huge limitations due to their low porosity, mechanical strength, and lack of direct cell-bioactive drug contact. Whereas bisphosphonate drug has the ability to stimulate osteogenesis in osteoblasts and bone marrow mesenchymal stem cells (hMSC) which attracted its therapeutic use. However it is hard administration low bioavailability, and lack of site-specificity, limiting its usage. The proposed scaffold architecture allows cells to access the bioactive surface at their apex by interacting at the scaffold's interfacial layer. The interface of 3D polycaprolactone (PCL) scaffolds has been coated with alendronate-modified hydroxyapatite (MALD) enclosed in a chitosan matrix, to mimic the native environment and stupulate the through interaction of cells to bioactive layer. Where the mechanical strength will be provided by the skeleton of PCL. In the MALD composite's hydroxyapatite (HAP) component will govern alendronate (ALD) release behavior, and HAP presence will drive the increase in local calcium ion concentration increases hMSC proliferation and differentiation. In results, MALD show release of 86.28 ± 0.22. XPS and SEM investigation of the scaffold structure, shows inspiring particle deposition with chitosan over the interface. All scaffolds enhanced cell adhesion, proliferation, and osteocyte differentiation for over a week without in vitro cell toxicity with 3.03 ± 0.2 kPa mechanical strength.     

2‐[(E)‐(4‐Hydroxy‐3‐methoxybenzylidene)amino]‐N‐(2‐methylphenyl)‐4,5,6,7‐tetrahydro‐1‐benzothiophene‐3‐carboxamide

The title compound, C₂₄H₂₄N₂O₃S, exhibits antifungal and antibacterial properties. The compound crystallizes with two molecules in the asymmetric unit, with one molecule exhibiting `orientational disorder' in the crystal structure with respect to the cyclohexene ring. The o‐toluidine groups in both molecules are noncoplanar with the respective cyclohexene‐fused thiophene ring. In both molecules, there is an intramolecular N—H...N hydrogen bond forming a pseudo‐six‐membered ring which locks the molecular conformation and eliminates conformational flexibility. The crystal structure is stabilized by O—H...O hydrogen bonds; both molecules in the asymmetric unit form independent chains, each such chain consisting of alternating `ordered' and `disordered' molecules in the crystal lattice.     

From Grignard's reagents to well-defined Mg nanostructures: distinctive electrochemical and solution reduction routes

Anisotropic Mg nanowires have been successfully prepared by electrocrystallization of Grignard's reagents thought to proceed via a modified faces, steps, and kinks (FSK) mechanism. Mg nanoparticles with roughly hexagonal shapes have also been obtained via chemical reduction of the same Grignard's reagents.     

NTCDA-TTF first axial fusion: emergent panchromatic, NIR optical, multi-state redox and high optical contrast photooxidation

The first synthetic entry into axially fused NTCDA/PMDA-TTF multipolar molecules demonstrates a high optical contrast photooxidation, panchromism, low HOMO-LUMO gap, generation of a stable radical cation, NIR absorption/emission beyond 2150/800 nm and theoretically calculated NLO activity.     

Gas chromatography electron ionization mass spectrometric analysis of trimethylsilyl derivatives of bis(2-hydroxyethylthio)alkanes and bis(2-hydroxyethylsulfonyl) alkanes

This communication describes GC-MS analysis of bis(trimethylsilyl) (bis-TMS) derivatives of bis(2-hydroxyethylthio)alkanes (BHETAs) and bis(2-hydroxyethylsulfonyl) alkanes (BHESAs) which are important markers of sulfur mustard class of chemical warfare agents. The study was undertaken with a view to develop spectral database of these compounds for verification analysis of Chemical Weapons Convention (CWC). Based on the obtained mass spectra of bis-TMS derivatives of BHETAs and BHESAs, the fragmentation routes are proposed, which explain most of the characteristic ions.     

Pointers toward the occurrence of C-F...F-C interaction: Experimental charge density analysis of 1-(4-fluorophenyl)-3,6,6-trimethyl-2-phenyl-1,5,6,7-tetrahydro-4H-indol-4-one and 1-(4-fluorophenyl)-6-methoxy-2-phenyl-1,2,3,4-tetrahydroisoquinoline

A charge density study of crystalline 1-(4-fluorophenyl)-3,6,6-trimethyl-2-phenyl-1,5,6,7-tetrahydro-4H-indol-4-one (A) and 1-(4-fluorophenyl)-6-methoxy-2-phenyl-1,2,3,4-tetrahydroisoquinoline (B) has been carried out using high-resolution X-ray diffraction data collected at 113(2) K. Weak intermolecular interactions of the type C-H...O, C-H...pi, and pi...pi hold the molecules together in the crystal lattice along with interactions of the type C-H...F and unusual C-F...F-C examined via charge density analysis. The topological features are evaluated in terms of Bader's theory of atoms in molecules through the first four criteria of Koch and Popelier. The C-F...F-C contact is observed to be across the center of symmetry in B and not in A, and further, this interaction appears to possess a certain correlation with the electron density properties at the critical point which suggests that such an interaction fits into the hierarchy of weak interactions.