Novel One-Pot Synthesis of Tetrasubstituted Phenolic Ketones and Sulphones

Reaction of tetrasubstituted cyclopentadienones 1,1a with phenacyl bromide 2, dichloroacetophenone 3, ethyl bromomalonate 4, bromomethyl-p-tolylsulphone 5 in 50% NaOH and in the presence of benzyltriethylammonium chloride gave the carbene adduct 6,7,7a as well as pentasubstituted phenols 8,9,9a,10,10a,11,11a. The carbene adducts 6,7 and 7a were also converted into the phenols 8,9,9a using t-BuOK or NaOH in refluxing t-BuOH.     

RP-HPLC Method for the Simultaneous Estimation of Eight Cardiovascular Drugs

The present study describes a convenient method for the separation and simultaneous determination of eight drugs used in cardiovascular diseases, viz., atenolol (ATN), lisinopril (LISI), hydrochlorothiazide (HCTZ), enalapril maleate (ENA), amlodipine besylate (AMLO), losartan potassium (LOSA), valsartan (VAL) and atorvastatin calcium (ATOR) in pharmaceutical formulations. A ZORBAX Rx-C8 column (250 × 4.6 mm, 5 μm particle size) was used with mobile phase consisting of acetonitrile, 10 mM dipotassium hydrogen phosphate buffer (pH 2.2 adjusted with orthophosphoric acid) using a gradient program and quantitative evaluation was performed at 210 nm with a flow rate of 1.0 mL min^?1. Suitability of this method for the quantitative determination of the drugs was proved by validation in accordance with International Conference on Harmonization guidelines. The method is selective, precise, robust, accurate and can be used for routine analysis of 15 combination pharmaceutical formulations in quality control.     

Near‐infrared Raman spectroscopic characterization of salivary metabolites in the discrimination of normal from oral premalignant and malignant conditions

In the present study, Raman spectroscopy has been employed in the discrimination of the saliva of normal subjects from patients with oral submucous fibrosis and oral squamous cell carcinomaat 785‐nm excitation. From the spectral signatures, prominent difference between normal and abnormal group because of variations in metabolic and pathological conditions of the subjects was observed. Principal component analysis coupled with linear discriminant analysis yielded a diagnostic sensitivity of 96.4 and 93.8% and a specificity of 70.2 and 95.7% in the classification of normal from premalignant and normal from malignant, respectively, confirming the efficacy of Raman spectroscopy in the classification of normal and oral abnormalities. Copyright © 2016 John Wiley & Sons, Ltd.     

Unusually Short Chalcogen Bonds Involving Organoselenium: Insights into the Se–N Bond Cleavage Mechanism of the Antioxidant Ebselen and Analogues

Structural studies on the polymorphs of the organoselenium antioxidant ebselen and its derivative show the potential of organic selenium to form unusually short Se???O chalcogen bonds that lead to conserved supramolecular recognition units. Se???O interactions observed in these polymorphs are the shortest such chalcogen bonds known for organoselenium compounds. The FTIR spectral evolution characteristics of this interaction from solution state to solid crystalline state further validates the robustness of this class of supramolecular recognition units. The strength and electronic nature of the Se???O chalcogen bonds were explored using high‐resolution X‐ray charge density analysis and atons‐in‐molecules (AIM) theoretical analysis. A charge density study unravels the strong electrostatic nature of Se???O chalcogen bonding and soft‐metal‐like behavior of organoselenium. An analysis of the charge density around Se?N and Se?C covalent bonds in conjunction with the Se???O chalcogen bonding modes in ebselen and its analogues provides insights into the mechanism of drug action in this class of organoselenium antioxidants. The potential role of the intermolecular Se???O chalcogen bonding in forming the intermediate supramolecular assembly that leads to the bond cleavage mechanism has been proposed in terms of electron density topological parameters in a series of molecular complexes of ebselen with reactive oxygen species (ROS).     

Design,synthesis, resolution,and stereochemical assignment of a conformationally rigid chiral ligand derived from anthracene and a dienophile containing a pyridine moiety

The conformationally rigid chiral ligand, trans-12-(pyridin-2-yl)-9,10-dihydro-9,10-ethanoanthracene-11-carboxylic acid ethyl ester, 1, was designed and synthesized in racemic form. Both isomers were successfully obtained in enantiomerically pure form through classical resolution using l-(+)-tartaric acid in acetonitrile. The nature of the diastereomeric complex formed in this resolution was elucidated using single crystal X-ray crystallographic studies. The absolute configuration of (+)-1 was unambiguously assigned as (11S,12S) by single crystal structural analysis of salt 5 formed from (+)-1 and l-(+)-tartaric acid.     

Sonication induced sheet formation at the air-water interface

A hydrophobic pentadecapeptide, AGAAAA-GAVVGGLGG (1), part of the prion sequence PrP (106-127), on fresh aqueous dissolution takes a mixture of random and sheet conformations which forms a stable monolayer with a high beta-sheet content when compressed at the air-water interface. This also develops into a kinetically stabilized beta-sheet structure on sonication.     

Synthesis of novel benzo naphtho naphthyridines from 2,4-dicloroquinolines

A schematic study on the condensation of 2,4-dichloroquinolines ( 1 ) with 1-naphthyamine ( 2 ) in the presence of CuI as a catalyst to functionalized mono ( 3 ) and di ( 4 ) substituted naphthylamino quinolines was described. Consequently, these mono- and di-substituted amines on polyphosphoric acid-catalyzed cyclization reaction with p-toluic acid and acetic acid to yield the linear benzo[b]naphtho[2,1-g][1,8]naphthyridines ( 5 ) and angular benzo[b]naphtho[2,1-h] naphthyridines ( 6 ) in good yields. In addition to descried the similar synthesis of benzo[g]naphtho [2,1-b][1,8]naphthyridines ( 12 ) and benzo[h]naphtho[2,1-g][1,8]naphthyridines ( 13 ) from 2,4-dichlorobenzo[h]quinoline ( 8 ) with various anilines ( 9 ) through my intermediates ( 10 and 11 ).     

Dielectric and conduction mechanism studies of Ni doped LiMn<Subscript>2</Subscript>O<Subscript>4</Subscript> synthesized by solution combustion method

In the present work, structural, morphological, dielectrical, and electrochemical properties of LiNi_xMn_(2-x)O₄ (where x?=?0, 0.1,0.3, 0.5 mol%) prepared by solution combustion method were reported. X-ray diffraction studies confirmed the formation of cubic spinel structure without any impurity phases. Scanning electron micrographs revealed grains of micrometer range with a spherical like morphology and narrow size distribution. Dielectric parameters such as dielectric constant, dielectric loss, impedance, and electrical modulus were found to depend on temperature, frequency, and dopant concentration. AC conductivity was found to increase with increase in temperature exhibiting negative temperature co-efficient of resistance (NTCR) property in the material. Complex impedance and electrical modulus studies revealed the existence of temperature-dependent electrical relaxation in the material. The Correlated Barrier Hopping (CBH) model of conduction mechanism was confirmed by the decrease in s parameter with increase in temperature. Charge-discharge studies revealed the stabilization of spinel lattice by Ni ions, contributing to better capacity retention.     

Effects of thermal barrier coating on the performance,combustion and emission of DI diesel engine powered by biofuel oil–water emulsion

Journal of Thermal Analysis and Calorimetry - Owing to the fast depletion of fossil fuels and their skyrocketing price due to the tremendous demand, they become imperative to find renewable...