Synthesis of Amides from Alcohols and Amines Through a Domino Oxidative Amidation and Telescoped Transamidation Process

The amide bond formation is of paramount importance in organic synthesis, both within academic research and industrial development and manufacturing of pharmaceutical chemicals and other biologically active compounds. Despite this fact, as well as the ever-increasing treatment costs of side streams and other environmental concerns regarding handling and transportation of hazardous reagents, contemporary synthesis has elicited few new reactions and methods for the preparation of amides. Herein, we reveal a high yielding and expedite two-step telescoped synthetic process that comprises a domino oxidative amidation and transamidation for the creation of amides. The process utilizes alcohols and amines as reaction pairs with TEMPO and Fe ions as catalytic system and 1,3-dichloro-5,5-dimethyl hydantoin as a terminal oxidant. The oxidative amidation and transamidation process is conducted under benign reaction conditions and short reaction time (approximate to 30 min.) in a two-step telescoped fashion by means of a multi-jet oscillating disk (MJOD) continuous-flow reactor platform. The disclosed process integrates alcohol oxidation and amide formation to afford target amide in yields up to 90%. The method operates with both primary and secondary amines together, but was hampered when bulky amines and/or alcohols were used as reagent/substrate.