Synthesis of oxabicyclo[3.3.1]nonenes and substituted tetrahydropyrans via (3,5)-oxonium-ene reaction

An efficient methodology for the synthesis of oxabicyclo[3.3.1]nonenes and substituted tetrahydropyrans has been developed in moderate yields from the reaction of geraniol with aldehydes and epoxides promoted by boron trifluoride etherate.     

A Simple and Convenient Synthesis of Pyrazinones

Pyrazinones were synthesized by reacting mesoionic azlactone [2‐aryl‐4‐methyl‐Δ²‐oxaxolin‐5‐one] and 1,4‐diazabutadienes in good yields at room temperature.     

Development of TUSCAT: A software for light scattering studies on spherical, spheroidal and cylindrical particles

An integrated software package TUSCAT (Tezpur University SCATtering Software) incorporated with a graphical user interface (GUI) was developed for modeling electromagnetic scattering from small particles and also to yield characteristic properties of the scattering particles from experimental data. Its interactive features enable the user to observe the changes in output scattering properties in real time. In addition to its ease of use, it has high computational accuracy, efficiency, reliability and adaptability.     

An efficient and reusable vanadium based catalytic system for room temperature oxidation of alcohols to aldehydes and ketones

A simple and efficient vanadium based catalyst system for the oxidation of primary and secondary alcohols to aldehydes or ketones is reported using tert-butyl hydroperoxide as oxidizing agent and vanadyl sulfate as catalyst at room temperature. The versatility of the catalytic protocol is studied with wide variety of substrates.     

Polymerization of Methyl Methacrylate by Charge-Transfer Mechanism with Amines and Carbon Tetrachloride

The charge-transfer complex formed between an amine and carbon tetrachloride can initiate the polymerization of vinyl monomers in a nonaqueous solvent such as dimethylsulfoxide. Here we use cyclopentylamine (CPA) and heptylamine (HA) as the donor compounds for charge-transfer initiation of the polymerization of methl methacrylate (MMA). The rate of polymerization R_p = k[MMA]¹ [amine]^0.5 [CCl₄]^0.5 when [CCl₄] [amine] ≤ 1; when [CCl₄] [amine] < 1, R_p becomes independent of [CCl₄] and R_p = k[MMA]^1.5 [amine]^0.5. The average constant at 60°C for the polymerization of MMA in terms of monomer were (1.66 ± 0.03) × 10^?5 and (1.46 ± 0.04) × 10^?5 s^?1 with CPA and HA, respectively, when [CCl₄] [amine] ≤ 1, and (1.16 ± 0.04) × 10^?5 and (1.39 ± 0.08) × 10^?1 L/mol·s when [CCl₄]/[amine] < 1.     

Sensitive and rapid determination of elemental nanosulfur/sulfur by liquid chromatography

In order to identify the most suitable method for the estimation of nanosulfur for studying its residue dynamics, the present work was taken up. HPLC and GC methods were explored for its analysis. A comparative study of the existing analytical methods for the quality control of nanosulfur was undertaken. UV spectrophotometry and HPLC methods were superior with lower LOD when compared to GC–MS, which was not satisfactory due to breakage of catenated S₂₀ into S₆ and S₈. The method has been validated by analyzing various nanosulfur formulations of known concentrations. The recovery of the UV and HPLC methods ranged from 80.71 to 109.51% and 82.31 to 109.84%, respectively. The LOD of UV, GC–MS, and HPLC is 4, 20, and 1 ppm, respectively. The retention time of sulfur was 13.77 (HPLC), 2.89 (ultra high performance liquid chromatography), and 12.715 + 21.524 min (GC–MS). The method was successfully utilized for estimating sulfur in natural samples such as water from a sulfur hot spring and wastewater. The method has been validated by following the method recommended by the American Society for Testing and Materials. The HPLC method emerged as the best analytical method for the estimation of elemental sulfur.     

Development and Validation of a High-Performance Thin-Layer Chromatography Method for the Quantification of Rutin in the Fruit Pulp of Benincasa hispida (Thunb.) Cogniaux

JPC – Journal of Planar Chromatography – Modern TLC - The fruits of Benincasa hispida (Thunb.) Cogniaux, a ‘rasayana’ in ‘Ayurveda’, are enriched with several...     

Dithiophosphinates of trivalent iron,ruthenium and osmium

Dithiophosphinates of Fe(III), Ru(III) and Os(III) have been prepared and their ESR studies indicate distortion from octahedral geometry. The tetragonal and rhombic splittings and the orbital reduction factors were calculated from the experimental g values for low-spin Ru(III) and Os(III) complexes. The metal-ligand covalency increases in the order Ru < Os.     

A highly efficient heterogeneous montmorillonite K‐10‐supported palladium catalyst for Suzuki–Miyaura cross‐coupling reaction in aqueous medium

A heterogeneous montmorillonite K‐10‐supported palladium triphenylphosphine catalyst is reported for the Suzuki–Miyaura cross‐coupling reaction at room temperature. A library of electronically diverse aryl bromides and arylboronic acids underwent the cross‐coupling reaction at very good rates in aqueous solvent. The reusability of the catalyst was also examined and it was found to be effective up to three catalytic cycles. Copyright © 2014 John Wiley & Sons, Ltd.