Thiourea-Catalyzed Amidation of Esters: A New Method for the Preparation of Amides

Although amides are one of the most abundant bonds in biology and medicinal chemistry, methods to prepare them are still limited. To expand on current methods for the formation of amides bonds, organocatalysts (thiourea-based) were developed to mediate the conversion of esters to amides. The reactions proceed in good to moderate yields and tolerate a variety of functional groups. ¹H NMR titration and computational studies show a strong hydrogen-bonding interaction between the thiourea catalyst and the ester moiety. This hydrogen-bonding interaction is proposed to be the driving force for the amidation of esters.