Jayashree M. Nagarkar

Choline chloride based eutectic solvent: an efficient and reusable solvent system for the synthesis of primary amides from aldehydes and from nitriles

Choline chloride: a 2ZnCl2 based deep eutectic solvent was found to be a simple, green, efficient and new solvent system for the preparation of primary amides from aldehydes. The same catalytic system is also applicable for the preparation of amides from nitriles. Good to excellent yields of primary amides were obtained in both these transformations.

Synthesis of 5-substituted 1H-tetrazoles using a nano ZnO/Co3O4 catalyst

Zinc salts have catalytically active sites suitable for synthesis of substituted 1H-tetrazoles. Herein we report the synthesis of 5-substituted 1H-tetrazoles catalyzed by nano ZnO/Co3O4. This is a novel heterogeneous catalyst which showed excellent efficiency, affording good to excellent yield of products.

Co-adsorption of quaternary ammonium compounds-nonionic surfactants on solid- liquid interface

Abstract Adsorption of mixed surfactants on the solid substrates has received scant attention in the past. However, in recent times, there have been a few investigations, which have been overviewed. Experimental results of co-adsorption and parallel zeta potential studies using mixed quaternary ammonium compounds CTAB, TTAB and nonyl phenyl ethoxylates (NP13, NP20, NP30) have been reported in this presentation. Three solid substrates, quartz, polystyrene and PTFE were chosen for investigation. ‘S’ shaped adsorption isotherms were obtained in case of all the three substrates. The presence of nonionics had varied effect on the adsorption of CTAB/TTAB depending on concentration. The zeta potential studies, in general, support the adsorption behaviour. However, the change on the solid substrate is influenced predominantly by the positively charged CTAB. Presence of premicellar aggregates on the solid surface is indicated. The nature of solid substrate appears to be of secondary importance.

Palladium(II) on Functionalized NiFe2O4: An Efficient and Recyclable Phosphine-Free Heterogeneous Catalyst for Suzuki Coupling Reaction

Superparamagnetic NiFe2O4 catalyst immobilized palladium(II) has been synthesized using a microemulsion method and functionalized with Schiff-base group to form an immobilized bidentate ligand. The catalyst was characterized by multiple analytical techniques. The immobilized palladium complex was used in EtOH/water under aerobic conditions. The catalyst is applicable for various substrates and easily separable. The as-prepared catalyst was reused up to five runs with slight decrease in catalytic activity.Graphical Abstract

Nano Pd–Fe3O4@Alg beads: as an efficient and magnetically separable catalyst for Suzuki, Heck and Buchwald–Hartwig coupling reactions

Catalytic processes are the backbone of many chemical industries. In a comparative study of various heterogeneous catalytic systems, we report efficient and magnetically separable nano Pd–Fe3O4@Alg beads as catalysts for Suzuki, Heck and Buchwald–Hartwig coupling reactions. This catalyst was characterized by SEM, TEM, HRTEM, XRD, EDAX, FT-IR, VSM, DSC-TGA, BET, and UV-Visible spectroscopy. This heterogeneous catalyst showed high catalytic activity and stability for C–C and C–N bond forming coupling reactions with excellent product yield under ligand free conditions. The beads of nano Pd–Fe3O4@Alg can be separated from the reaction mixture by an external magnet and reused for several successive cycles with no appreciable loss in the catalytic activity. The Suzuki and Heck coupling reactions in aqueous medium are greener routes, which is an added advantage of this protocol.

An efficient catalyst-free and chemoselective synthesis of azobenzenes from nitrobenzenes

NaOH mediated reaction of nitrobenzenes in EtOH was performed at 80 °C temperature affording azobenzenes in excellent yield. This methodology presents an easy synthesis of a wide variety of azo compounds from readily available nitrobenzene derivatives.

Copper catalyzed synthesis of unsymmetrical diaryl sulfones from an arenediazonium salt and sodium p-toluenesulfinate

Aryl sulfones have been for the first time synthesized by the reaction of sodium p-toluenesulfinate and arenediazonium salts using a CuI catalyzed homogeneous system. The developed protocol is a simple and efficient new route for the synthesis of diaryl sulfones with excellent product yields. The mild reaction conditions tolerate a range of functional groups. The best results were obtained with CuI, N,N′-dimethylethylenediamine, TBAI and K2CO3 in dimethyl sulfoxide at 100 °C under an inert atmosphere.

A Simple Metal Free Oxidation of Sulfide Compounds

AbstractThis work reports simple, efficient, selective protocol for the oxidation of sulfide compounds. Various sulfides were selectively and completely converted into their corresponding sulfoxides and sulfones using H2O2 as an oxidant in presence of catalytic amount of caprylic acid. The reaction proceeds at room temperature to give sulfoxide and by increasing the reaction temperature to 50 °C, this system provides selective formation of sulfone with high conversion and excellent yields. Green, convenient, easy work-up, chemoselectivity, broad substrate scope and regeneration of catalyst are the important highlights of this protocol.Graphical Abstract Using H2O2 as an oxidant in presence of catalytic amount of caprylic acid various sulfides were selectively and completely converted into their corresponding sulfoxides and sulfones.

An efficient magnetic copper ferrite nanoparticle catalysed ligand and solvent free synthesis of N-aryl amide from aldoximes and iodobenzene

A simple, efficient, and environmentally benign method has been reported for the synthesis of N-aryl amides using aldoximes and iodobenzene under ligand free and solvent free conditions and using magnetically separable copper ferrite nanoparticles as catalyst. The catalyst was characterised using XRD, FEG-SEM, EDAX, ICP-AES and TEM and tested for recyclability for up to five cycles.

Efficient Sonogashira and Suzuki-Miyaura coupling reaction catalyzed by Pd-Nanoparticles

AbstractThe Pd nano particles were electrochemically deposited on nafion-graphene. They showed excellent catalytic activity towards Sonogashira and Suzuki-Miyaura cross-coupling reaction. Benzenediazonium salts were used as alternative to aromatic halide. The developed protocol offers recyclability, easy workups with short reaction time and good-to-excellent product yield. Graphical Abstract The Pd nano particles were electrochemically deposited on nafion-graphene. They showed excellent catalytic activity towards Sonogashira and Suzuki-Miyaura crosscoupling reaction. Benzenediazonium salts were used as alternative to aromatic halide