A comparative study of amide -bond forming reagents in aqueous media - Substrate scope and reagent compatibility

A survey of amidation reagents demonstrating DIC-HOPO, DMT-MM, COMU-collidine, TPTU-NMI, EEDQ, CDI and EDC-Oxyma to be effective for the coupling of carboxylic acids with amines in the presence of water and the absence of problematic dipolar aprotic solvents is reported. DMT-MM was shown to provide the best yields for the coupling of a secondary amine, TPTU-NMI and COMU-collidine for aniline, whilst the combination of DIC with HOPO afforded the broadest substrate scope and the highest yields for a sterically demanding carboxylic acid. (C) 2017 Elsevier Ltd. All rights reserved.