Bmim(OH)/chitosan/C 2 H 5 OH synergy: grinding induced, a new route for the synthesis of spiro-oxindole and its derivatives

Here we report a synthetic strategy based on the synergistic effect of a catalyst system incorporating Bmim(OH), chitosan and C2H5OH. This powerful catalyst system is very effective and has several advantages such as being cost effective, involving shorter reaction times, being high yielding, involving the formation of no by-products and most importantly its easy recyclability (at least three times) with negligible reduction in its catalytic properties.