Novel Applications of Some Hypervalent Iodine Reagents in Organic Transformations

Abstract

The thesis explores the novel applications of commonly used hypervalent iodine(III) newlinereagents in the synthesis of some key Intermediates and heterocyclic compounds ranging newlinefrom classical five-membered rings to small indole containing natural products. newlineThe first chapter briefly summarizes the development of hypervalent iodine chemistry newlinealong with their general aspects of bonding, structure, chemical properties and synthetic newlineapplications. newlineThe second chapter describes the utility of benign [hydroxy(tosyloxy)iodo]benzene newlinereagent (HTIB) in the solvent-free synthesis of and#945;-azidoketones in the presence of newlinetetrabutyl ammonium bromide (TBAB). newlineThe third chapter comprises of two parts: Part A deals with a one-pot solvent-free newlinesynthesis of and#946;-keto sulfones from enolizable ketones using [hydroxy(tosyloxy)iodo]benzene. newlinePart B describes the solvent-free synthesis of novel and#945;-tosyloxy-and#946;-keto sulfones from newlinecorresponding and#946;-keto sulfones using HTIB at room temperature. newlineIn the fourth chapter, Part A focuses on HTIB-mediated simple and efficient synthesis of newlinenaturally occurring 5-(3and#8242;-indolyl)azoles. Formation of 3-tosyloxyacetyl-1-benzenesulfonylindole newlineutilizing HTIB and cyclodehydration of and#945;-acylaminoketone in the presence newlineof p-toluenesulfonic acid, are the key-steps of this novel synthesis. The present work newlinehighlights the formation of hitherto unknown 3-tosyloxyacetyl-1-benzenesulfonylindole newlineby the reaction of 3-acetyl-1-benzenesulfonylindole with HTIB. The intermediate newlineand#945;-acylaminoketone was also utilized in the synthesis of 5-(3and#8242;-indolyl)thiazoles and newline5-(3and#8242;-indolyl)imidazoles, known as bioisosteres of naturally occurring newline5-(3and#8242;-indolyl)oxazoles. Part B of this chapter discusses the direct synthesis of newline5-(3and#8242;-indolyl)oxazoles from 3-acetyl-1-benzenesulfonylindole using appropriate nitrile in newlinethe presence of [hydroxy(2,4-dinitrobenzenesulfonyloxy)iodo]benzene (HDNIB). newlineIn the fifth chapter, synthesis and anticancer activity of novel 5-(3and#8242;-indolyl)-2-substituted- newline1,3,4-oxadiazoles, bioisosteres of naturally occurring 5-(3and#8242;-indolyl)oxazole