Synthesis of novel biologically active organic compounds

Abstract

The thesis entitled SYNTHESIS OF NOVEL BIOLOGICALLY ACTIVE ORGANIC COMPOUNDS is divided into five chapters. Chapter 1 deals with general survey of literature on and#945;-hydroxy esters, o-acyl mandelic esters and review on importance of N-heterocyclic carbenes in organic chemistry. The chapters 2, 3, and 4 deal with the general survey of literature on the importance of N-heterocyclic carbenes in reduction, hydroacylation and coupling reactions and their use in synthesis of a novel aromatic compounds and experimental procedure for our synthesis of those novel aromatic compounds. Chapter 5 deals with summary and conclusion. Chapter-I: Introduction on N-heterocyclic carbenes In this chapter presents an overview of literature survey on and#945;-hydroxy esters, o-acyl mandelic esters. Also presents review on N-heterocyclic carbenes and its applications in organic chemistry or synthesis of active intermediates. Chapter-II: Synthesis of novel and#945;-hydroxy esters, o-acyl mandelic esters by reduction/hydroacylation of activated ketones with aldedhydes mediated by 1, 3-Bis(2,4,6-trimethylphenyl)imidazolium chloride: In this chapter, we have reported novel and#945;-hydroxy esters and o-acyl mandelic esters by reduction/hydroacylation of and#945;-ketoesters with aldehydes by of 1,3-bis(2,4,6-trimethyl phenyl)imidazolium chloride and triethylamine at ambient temperature via generating N-heterocyclic carbene insitu. An improved catalytic system for hydroacylation/reduction of activated ketones NHC -mediated reduction of and#945;-keto esters in protic solvent Screening of NHC ligands (A-D) with different Bases: xiii The reaction of benzaldehyde 1a with methyl 2-(2-chlorophenyl)-2-oxoacetate 2a in the presence of salts A D (Figure 1) using various bases in methanol (Scheme1). As expected, the carbonyl reduction product 4a was isolated. Among all the salts screened, the use of sterically encumbered 1,3-bis(2,4,6-trimethylphenyl)imidazolium chloride A was found to be the most effective in terms of product yield.