1, 3-Dipolar cycloaddition reaction of aryl nitrile oxides with alkenes using imidazole and pyridine containing reusable polymeric base catalysts. Issue 4 (16th February 2018) - Korgavkar, Nilesh N.
ABSTRACT: Cross-linked poly-1-(4-vinylbenzyl)imidazole and cross-linked poly-4-vinylpyridine have been prepared from respective vinyl monomers using different quantities of divinylbenzene as a cross-linker by radical polymerization. The polymeric bases were characterized by FT-IR, TGA, field emission-scanning electron microscopy (FE-SEM), and Brunauer-Emmett-Teller (BET) surface area analysis. Their swelling behavior was also studied. They were used as base catalysts for 1, 3-dipolar cycloaddition reaction of aryl nitrile oxides, generated in situ from N -hydroxyimidoyl chloride, with N -phenylmaleimide and ethyl acrylate, to obtain 3-arylisoxazolines. Both the bases gave excellent results. These polymers were reusable, safe to use, and provided good alternative for organic nonreusable bases like pyridine and triethylamine which are hazardous. GRAPHICAL ABSTRACT: