SYNTHESIS of INDANONE BASED SPIROCYCLIC MOLECULES FOLLOWING 1 3 DIPOLAR CYCLOADDITION REACTION

Abstract

The search for the efficient transformation of simple starting materials to highly functionalized complex products that combine economic, environmental and green aspects has been an active objective in organic synthesis. In this regard, the development and use of multi-component reactions (MCRs) have emerged as a highly valuable synthetic tool to fulfill this goal. In recent years, the area of 1,3-dipolar cycloaddition reactions has been well developed for the synthesis of spiro-heterocycles via multicomponent fashion. Spiro heterocycles are ubiquitously imperative structural units of many natural or synthetic molecules and constitute the largest diversity of organic molecules of chemical, biomedical, and industrial significance. One of the most effective direct methods for the synthesis of spiroheterocycles with pyrrolidine and pyrrolizidine rings following intermolecular 1,3-dipolar cycloaddition of azomethine ylides to dipolarophiles have attracted the attention of synthetic organic chemists because of their highly pronounced pharmacological and biological activities such as anti-tumor, anti-cancer, anti-bacterial, antioxidant and acetylcholine esterase inhibitory activity etc and also serve as synthetic intermediates of drug precursors. The 1,3-dipolar cycloaddition (1,3-DC) reactions of azomethine ylides with olefin is an elegant and efficient methodology for regio- and stereoselective synthesis of structurally complex pyrrolidine and spiropyrrolidine heterocycles from relatively simple precursors. Nitrogen containing heterocycles constructed through 1, 3-dipolar cycloaddition of azomethine ylides generated insitu from the decarboxylative condensation of carbonyl compounds with and#945;-amino acids have been well documented and are widely applied in organic synthesis for the construction of important cluster of significant bioactive compounds .In recent years, spiro indenoquinoxaline-pyrrolidines, prepared from 1,3-DC between azomethine ylides with olefinic dipolarophiles, have attracted t