Ultrasound Promoted Oxamate Synthesis: A Chemoselective and Direct Approach from Amines

Abstract

AbstractUltrasound (US) assisted, catalyst and oxidant free, chemoselective protocol for the synthesis of diverse oxamates from oxalic acid and amines with alcohol is demonstrated efficiently. In situ formation of the corresponding esters from oxalic acid and alcohols reacts with amines and augments the formation of desired oxamates in remarkable yields under the employed reaction conditions. This protocol is amine‐selective, can tolerate other functional groups and also applicable for gram‐scale synthesis. When compared with conventional (NUS) method, the US method is found to be more superior in terms of reaction time and total energy consumption (84‐87% of energy is saved). The synthesized products are well characterized by 1H, 13C, and IR spectroscopic techniques.