Metal free montmorillonite KSF clay catalyzed practical synthesis of benzoxazoles and benzothiazoles under aerobic conditions

An efficient method for the synthesis of benzoxazoles and benzothiazoles via montmorillonite KSF clay catalyzed condensation reaction between 2-aminophenols or 2-aminothiophenols and β-diketones is reported. The efficiency of the reaction reflects from the wide substrate scope with electronic differentiation on aryls. The reaction is metal free and proceeds without the exclusion of air or moisture, and further the catalyst can be recycled up to 3–5 catalytic cycles.     

Synthesis of Novel 2-Amino-N-hydroxybenzamide Antimicrobials

New 2-amino-N-hydroxybenzamide derivatives (3a–j) have been synthesized in good to excellent yields from the reaction of isatoic anhydride with different hydroxamic acids. All the compounds of the series were screened against both Gram-positive and Gram-negative bacteria and fungi, and some of them have antibacterial and antifungal activities compared to the standard drugs.     

Facile Synthesis of Second-Generation Dendrons with an Orthogonal Functional Group at the Focal Point

Facile synthesis of second-generation dendrons with an aldehyde, epoxy, or t-Boc group at the focal point and nine carboxylic acid groups at the periphery is reported. The scheme includes a coupling of the first-generation dendrons and a two-step, one-pot reaction that proceeds through a Boc deprotection and in situ conjugation at the focal point.     

Synthesis,Characterization, and Antiproliferative Activity of 2-(2-Bromo-5-methoxyphenyl)-6-aryl-1,3-thiazolo[3,2b][1,2,4]triazoles

Eight new 2-(2-bromo-5-methoxyphenyl)-6-aryl-1,3-thiazolo[3,2-b][1,2,4]triazoles were synthesized by treating 5-(2-bromo-5-methoxyphenyl)-4H-1,2,4-triazole-3-thiol with phenacyl bromides. The new products were characterized by spectroscopic and analytical methods. Five of the new compounds were evaluated for their antiproliferative activity. 2-(2-Bromo-5-methoxyphenyl)-6-(3,4-dihydroxyphenyl)-1,3-thiazolo[3,2-b] [1,2,4]triazole exhibited promising activity.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

New polymer electrolyte based on (PVA–PAN) blend for Li-ion battery applications

A polymer blend electrolyte based on polyvinyl alcohol (PVA) and polyacrylonitrile (PAN) was prepared by a simple solvent casting technique in different compositions. The ionic conductivity of polymer blend electrolytes was investigated by varying the PAN content in the PVA matrix. The ionic conductivity of polymer blend electrolyte increased with the increase of PAN content. The effect of lithium salt concentrations was also studied for the polymer blend electrolyte of high ionic conductivity system. A maximum ionic conductivity of 3.76×10⁻³ S/cm was obtained in 3 M LiClO₄ electrolyte solution. The effect of ionic conductivity of polymer blend electrolyte was measured by varying the temperature ranging from 298 to 353 K. Linear sweep voltammetry and DC polarization studies were carried out to find out the stability and lithium transference number of the polymer blend electrolyte. Finally, a prototype cell was assembled with graphite as anode, LiMn₂O₄ as cathode, and polymer blend electrolyte as the electrolyte as well as separator, which showed good compatibility and electrochemical stability up to 4.7 V.     

Surface energy effect on boiling heat transfer

Boiling is a complex phenomenon and depends upon many factors like liquid properties, liquid pressure and temperature, temperature of the heating surface, orientation of the heating surface, surface chemistry, etc. Study of the effect of surface energy, one such factor, on boiling heat transfer is carried out and presented here. Data for various fluids viz. water, different types of alcohols and for various surfaces has been collected from the open literature and analysed with regard of effect of surface energy. The results of the investigations along with the recommendations have been presented in this paper. The investigations have shown that the increase in surface energy has resulted in increase in the heat transfer coefficient for distilled water, while the increase in surface energy has resulted in decrease in the heat transfer coefficient for alcohols. There is scarcity of relevant data available for further investigation and in this regard, need for benchmark data has been raised. Also need for establishment of a standard for comparison and analysis of different experimental results has been put forth.The paper is dedicated in honor of Sir Isaac Newton, a genius scientist whose greatness is beyond words. But, he was much more than that. He was an animal lover, a man of peace, a man of character, a man of holiness, purity...! A saint! Light!! Love!!!     

Mass spectrum of elementary particles in a temperature-dependent model

We show that the temperature-generalization of a popular model of quark-confinement seems to provide a rather interesting insight into the origin of mass of elementary particles: as the universe cooled, there was an era when particles did not have an identity since their masses were variable; the temperature at which the conversion of these ‘nomadic’ particles into ‘elementary’ particles took place seems to have been governed by the value of a dimension-less coupling constantC _c. ForC _c=0.001(0.1) this temperature is of the order of 10⁹ K (10¹¹ K), below which the particle masses do not change.     

Effect of temperature and yeast extract on microbial respiration of sediments from a shallow coastal subsurface and vadose zone

Applied Biochemistry and Biotechnology - As a part of our study on microbial heterogeneity in subsurface environments, we have examined the microbial respiration of sediment samples obtained from a...     

Three-dimensional microwell arrays for cell culture

We propose the concept of three-dimensional (3D) microwell arrays for cell culture applications and highlight the importance of oxygen diffusion through pores in all three dimensions to enhance cell viability.