An Efficient and Facile Multicomponent Reaction for the Synthesis of 5′,6′‐dihydro‐6′‐hydroxy‐6′‐(trifluoromethyl)‐1′H‐spiro[indoline‐3,4′‐pyrimidine]‐2,2′(3′H)‐dione Derivatives under Solvent‐Free Conditions

Abstract

The reactions of isatins, urea, and different diketones under solvent‐free conditions have been developed for the preparation of novel spiroheterocycles. It was found that these reactions could be given higher yields and required shorter time compared with commonly used volatile organic solvent conditions. In this synthesis, the important group trifluoromethyl was introduced into the structure of the products. The pure products could be obtained only through removing TsOH, isatins, and urea from hot water. At same time, diketone was eliminated through a small amount of EtOH. Other advantages of this method are simple setup, mild conditions, and minimal environment impact.