Prakash J. Saikia

(DHQD)2PHAL ligand-accelerated Cu-catalyzed azide–alkyne cycloaddition reactions in water at room temperature

Herein, we have described, a ‘Click Chemistry’ protocol for the rapid synthesis of 1,2,3-triazoles in water. (DHQD)2PHAL has been found to be an excellent accelerating ligand for the copper(I)-catalyzed azide–alkyne cycloaddition reaction under air. The procedure is simple, efficient, environmentally-friendly and the products were isolated in excellent yields with high purity.

Electrolyte effect on the particle characteristics prepared by soap-free emulsion polymerization

Monodisperse micron-sized polystyrene (PS) spheres were successfully obtained using a single stage soap-free emulsion method in aqueous media mixed with ethanol (co-solvent) containing NaCl as the electrolyte. The optimum conditions for preparing the monodisperse PS microspheres, using soap-free emulsion polymerization in a water/ethanol mixture with an electrolyte, were studied. The presence of the co-solvent and electrolyte controlled the particle dispersion stability during the polymerization. The microspheres formed using PS, with a weightaverage diameter of 2.6 εm, coefficient of variation of 5.3% and zeta potential of −15.1 eV, were successfully obtained in the presence of 0.1 wt% NaCl, 10 wt% monomer, 0.1 wt% initiator and 95/5 (g/g) of a water/ethanol mixture reacted at 70°C for 24 h.

CTAB promoted CuI catalyzed green and economical synthesis of 1,4-disubstituted-1,2,3-triazoles

ABSTRACT A practical, straightforward, and highly efficient CuI mediated green protocol for the regioselective synthesis of 1,4-disubstituted-1,2,3-triazole was developed using cetyltrimethylammonium bromide as a cheap additive in good to excellent yields. Low catalyst loadings, environmentally friendly solvent, wide substrate scope and short reaction times at room temperature make this strategy more accessible and safe. GRAPHICAL ABSTRACT

A potential greener protocol for peptide coupling reactions using recyclable/reusable ionic liquid [\(\hbox {C}_{4}\hbox {-DABCO}][\hbox {N(CN)}_{2}\)]

Development of greener methodologies in synthetic organic chemistry has brought awareness in recent decades due to the ecological performance of green solvent media and catalytic systems. Here, we carried out the peptide bond formation reaction in one of the environmentally secure solvents, ‘ionic liquids’ in the presence of coupling reagent and in the absence of external base at room temperature, affording dipeptides in good to excellent yields. SYNOPSIS We carried out the peptide bond formation reaction in ionic liquids in the presence of a coupling reagent at room temperature, in the absence of an external base, affording dipeptides in good to excellent yields.