An expedient synthesis of new imino-thiazolidinone grafted dispiro-pyrrolidine-oxindole/indeno hybrids via a multicomponent [3+2] cycloaddition reaction in a deep eutectic solvent

Abstract

An expedient, one-pot regio- and stereo-selective synthesis of new imino-thiazolidinone grafted dispiro-pyrrolidine hybrids has been accomplished successfully by a green and sustainable method. The synthesis included a three component [3+2] cycloaddition reaction of 2-(arylimino)thiazolidin-5-ylidenes, substituted isatin/ninhydrin and sarcosine using choline chloride (ChCl) : urea (1 : 2) as a deep eutectic solvent (DES) in a single step. Among the variety of reaction conditions, the utilization of choline chloride : urea (1 : 2) at 80 °C was found to be the most effective reaction condition to achieve desired dispiropyrrolidines in excellent yield with high regio- and stereo-selectivity. This method is operationally simple with cleaner conversion to afford the target compounds in short reaction times and avoids the use of environmentally hazardous solvents, which make this globally putative. Moreover, the ChCl : urea (1 : 2) can be reused for over three repeated cycles without any noteworthy loss of activity.