An Effective and Environmentally Friendly One-pot Multicomponent Approach for the Synthesis of spiroannulated hybrid molecules with Preferred Substructures using Indium Triflate as an efficient and Reusable Catalyst

Abstract

An Effective and Environmentally friendly, In(OTf)3 catalysed multicomponent approach to the synthesis of spiroannulated indolinequinolines, indoline pyridopyrimidines, chromeno pyridineindolines and indeno pyridineindolines has been presented the first time. The current approach uses an indium triflate catalyst in a one-pot four-component reaction of isatin, malononitrile, 1,3-Diketone, and 4-ethylaniline in ethyl alcohol. The current protocol presents multiple advantages that including operational simplicity with easy workup, moderate reaction conditions, shorter reaction times (25-40 min), excellent yields (85-96%) with superior atom economy, and environmentally friendly reaction conditions due to the use of recyclable, and non-hazardous catalyst.