Transamidation esterification and thio esterification of N activated amides

Abstract

Amides are incredibly prevalent and play a crucial role in various biological systems, natural newlineproducts, and pharmaceuticals. The prevalence of amides in various systems underscores the newlineimportance of synthesis and conversion of amide functionality. newlineThe presented thesis work outlines a novel approach in organic synthesis focusing on the trans- newlineformation of typically stable and less reactive amides into various compounds, such as different newlineamides, esters, and thioesters. Conventionally, amides are considered stable building blocks newlinebut are often challenging to modify due to their inherent stability. In this research, a method- newlineology was demonstrated to convert amides into diverse products by activating them through newlineN-activation using electron-withdrawing groups like the carbonyl functional group. This acti- newlinevation process facilitated the conversion of amide bonds into different chemical entities. newlineThe first method involved incorporating amides with 2-piperidinone, resulting in N-acyl-2- newlinepiperidinones, which served as activated amides. These activated amides were then reacted newlinewith various aryl amines under environmentally friendly conditions without the use of sol- newlinevents, catalysts, additives, or bases. The reaction occurred simply by stirring the N-acyl-2- newlinepiperidinones and amines at an elevated temperature (120and#9702;C) i.e under melt condition, yielding newlinetransamidation products in a relatively short time frame. This method demonstrated excellent newlineefficiency in producing the desired products, showcasing its versatility with different functional newlinegroups and its applicability in synthesizing natural products and drug molecules. newlineThe second strategy employed pivaloyl as an amide-activating agent. The N-pivaloyl-activated newlineamides underwent reactions with various alkyl and aryl amines, alcohols, and thiols, leading newlineto the formation of amides, esters, and thioesters. The esterification and thioesterification re- newlineactions necessitated the presence of a catalytic amount of DABCO for efficient conversion. newlineFurthermore, we conducted addit