Enantiodivergent synthesis of both enantiomers of gypsy moth pheromone disparlure

Enantiodivergent synthesis of both (-)- and (+)-disparlure, a bioactive pheromone, possessing a cis-epoxide has been accomplished. The key step involves the cross metathesis of a chiral homoallylic alcohol derived from l-(+)-tartaric acid.     

A new class of discotic mesogens derived from tris(N-salicylideneaniline)s existing in C3h and Cs keto-enamine forms

Two series of a unique class of columnar liquid crystals derived from tris(N-salicylideneaniline)s [TSANs] in which the proton and the electron interact with each other through the H-bonding environment are reported. The synthesis is carried out by condensing 1,3,5-triformylphloroglucinol with the respective dialkoxyanilines or trialkoxyanilines. 1H NMR and 1H-1H COSY NMR studies revealed their existence as an inseparable mixture of two keto-enamine tautomeric forms with C3h and Cs rotational symmetries instead of the expected enol-imine form. The influence of the number of peripheral alkoxy tails on the columnar mesomorphic behavior is investigated by using polarizing optical microscopy, differential scanning calorimetry, and X-ray scattering. The fluid/glassy columnar states probed for a number of representative compounds confirmed the D6h (hexagonal) or D2h (rectangular) symmetry of the columns. The electronic absorption and emission characteristics of these compounds have been studied in both mesomorphic and solution states. Of special interest, the photoluminescence spectra of solution and fluid/glassy two-dimensional structure evidently disclose the promising light generating capability of these new discotics systems.     

Determination of mammalian lignans in biological samples by modified gas chromatography/mass spectrometry

Lignans in flaxseed have been part of the human diet for centuries. In 1955, the isolation and structure of the lignan derivative secoisolariciresinol diglucoside (SDG) was reported. The biological role of SDG and mammalian lignan metabolites enterodiol and enterolactone was initially reported 20 years later. Experimental evidences showed the beneficial effects of lignans on breast, colon, and thyroid cancer. A modified gas chromatography/mass spectrometry (GC/MS) assay was developed for lignans in serum and colon samples of rats fed flaxseed meal. The method developed for the analysis of metabolites involves extraction and derivatization of samples and quantitative analysis by selected ion monitoring using GC/MS. The levels of lignan metabolites enterodiol and enterolactone were determined to be 0.013 and 0.23 microM in serum samples and 0.008 and 1.63 microM in colon samples.     

Seaweed Polysaccharide Based Products and Materials: An Assessment on Their Production from a Sustainability Point of View

Among the various natural polymers, polysaccharides are one of the oldest biopolymers present on the Earth. They play a very crucial role in the survival of both animals and plants. Due to the presence of hydroxyl functional groups in most of the polysaccharides, it is easy to prepare their chemical derivatives. Several polysaccharide derivatives are widely used in a number of industrial applications. The polysaccharides such as cellulose, starch, chitosan, etc., have several applications but due to some distinguished characteristic properties, seaweed polysaccharides are preferred in a number of applications. This review covers published literature on the seaweed polysaccharides, their origin, and extraction from seaweeds, application, and chemical modification. Derivatization of the polysaccharides to impart new functionalities by chemical modification such as esterification, amidation, amination, C-N bond formation, sulphation, acetylation, phosphorylation, and graft copolymerization is discussed. The suitability of extraction of seaweed polysaccharides such as agar, carrageenan, and alginate using ionic solvent systems from a sustainability point of view and future prospects for efficient extraction and functionalization of seaweed polysaccharides is also included in this review article.     

Investigation of liquid crystalline property of a new calamitic liquid crystalline system methyl 4-(4ʹ-(4ʹʹ-(decyloxy)benzyloxy) benzylideneamino)benzoate

A new polar calamitic liquid crystal, methyl 4-(4?-(4?-(decyloxy)benzyloxy) benzylideneamino)benzoate (M3BA) containing ether and Schiff base groups as linker with terminal polar ester group, has been synthesised and mesomorphic properties are studied by differential scanning calorimetry, polarising optical microscopy, density functional theory, temperature-dependent X-ray diffraction and temperature-dependent micro- Raman study. The smectic A (SmA) mesophase with focal conic texture has been observed with wide mesomorphic range. Layer thickness in SmA phase is greater than the optimised length of the molecule, indicating partially bilayer SmA phase. Analysis of Raman marker bands of C–H in-plane bending of phenyl rings, C=C stretching of rings, C=N stretching and C=O stretching shows structural changes at molecular level at Cr → SmA phase transition and provides proper intermolecular interactions responsible for dimeric unit in partially bilayer SmA phase.     

Transparent hydrophobic and superhydrophobic coatings fabricated using polyamide 12–SiO2 nanocomposite

Optically transparent hydrophobic and superhydrophobic coatings have been prepared using polyamide 12–SiO₂ nanocomposite (NC) on glass substrates by the spin‐coating method. The coatings have been optimized for their hydrophobicity and transparency. The transformation from hydrophobic to superhydrophobic is achieved with increase in roughness (R_a) which increases with SiO₂ content. These coatings are highly transparent in the entire visible region (400–800 nm). The influence of layer thickness on water contact angle (WCA) and optical transmittance of the coatings has been studied. Field emission scanning electron micrograph (FESEM) shows the presence of SiO₂ nanoparticles covered with polyamide homogenously on the surface and the particles are aggregated to form a rough structure. X‐ray diffraction (XRD) patterns show that the polyamide losses its crystalline structure in the composite. The preparation procedure reported here is simple and eco‐friendly. The dual nature of the coatings, that is, high transparency and superhydrophobicity in the entire visible region suggests for its potential usage in self‐cleanings, wind screen and optoelectronic applications. Copyright © 2016 John Wiley & Sons, Ltd.     

Multi Fuzzy Fractal Theorems in Fuzzy Metric Spaces

The Hutchinson-Barnsley (HB) operators are studied for multi iterated function system in a general setting. Some existence and uniqueness results are obtained in fuzzy fractal and multi fuzzy fractal spaces. From them, we obtain our results, which generalize some recent results in the literature.     

Rovibrational spectra of bounded diatomic molecules

Spectra of a bounded diatomic molecule is studied numerically. Shifted Deng–Fan oscillator potential has been used to model the molecule. The accurate five‐point finite difference method has been used to solve the Schrödinger equation for rovibrational motion of the molecule. The energies of the bound states as well as free states of the molecule have been calculated. In addition, radial matrix elements like , n = 1, 2, and 3 have been calculated. These have been used to calculate the ‐pole static polarizabilities. The variation of bound state energies, matrix elements and ‐pole static polarizabilities with the boundary radius has also been studied. The Stark effect in case of this bounded system has also been investigated.     

Synthesis and characterization of novel benzoxazine-based arylidinyl succinimide derivatives

1,4-Benzoxazine skeleton holds substantial promise for further exploration owing to its immense pharmacological potential. In this pursuit, a series of 20 novel benzoxazine-based arylidinyl succinimide derivatives (23–42) were synthesized in moderate to good yields by the reaction of ethyl 2-(7-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)-3-oxo-2H-benzo[b][1,4]oxazin-4(3H)-yl)acetate (22) with various aromatic aldehydes under Wittig reaction conditions in the presence of triphenylphosphine and ethanol. All these synthesized compounds were fully characterized from their spectral data (¹H, ¹³C, and ²D NMR, IR, UV, high-resolution mass spectroscopy (HRMS)) and further confirmed by X-ray crystallographic analysis of a representative compound (32). Antibacterial activity of obtained arylidinyl succinimide derivatives was evaluated against both Gram-positive and Gram-negative bacterial strains and were found to exhibit insignificant activity as compared to the reference.     

Quality-by-design-based development and validation of a stability-indicating UPLC method for quantification of teriflunomide in the presence of degradation products and its application to in-vitro dissolution

A systematic design-of-experiments was performed by applying quality-by-design concepts to determine design space for rapid quantification of teriflunomide by the ultraperformance liquid chromatography (UPLC) method in the presence of degradation products. Response surface and central composite quadratic were used for statistical evaluation of experimental data using a Design-Expert software. The response variables such as resolution, retention time, and peak tailing were analyzed statistically for the screening of suitable chromatographic conditions. During this process, various plots such as perturbation, contour, 3D, and design space were studied. The method was developed through UPLC BEH C18 2.1?×?100?mm, 1.7-µ column, mobile phase comprised of buffer (5?mM K₂HPO₄ containing 0.1% triethylamine, pH 6.8), and acetonitrile (40:60 v/v), the flow rate of 0.5?mL?min^?1 and UV detection at 250?nm. The method was developed with a short run time of 1?min. Forced degradation studies revealed that the method was stability-indicating, suitable for both assay and in-vitro dissolution of a drug product. The method was found to be linear in the range of 28–84?µg?mL^?1, 2.8–22.7?µg?mL^?1 with a correlation coefficient of 0.9999 and 1.000 for assay and dissolution, respectively. The recovery values were found in the range of 100.1–101.7%. The method was validated according to ICH guidelines.