Reductive Amination of Biomass-Based Levulinic Acid into Pyrrolidone by Protic Ionic Liquid via Dehydrogenation of Dimethyl Amine Borane

Pyrrolidones has gained much attention because of extensive use in agrochemical, pharmaceutical, industrial materials and chemical production. In that context, we demonstrated a novel and highly competent protocol for the reductive amination of biomass-based levulinic acid into N-alkyl pyrrolidone. The protic ionic liquid (PIL) [HmPip][OTf] used in this study plays a dual role as a catalyst for reductive amination as well as for dehydrogenation of dimethylamine borane complex (DMAB). Metal-free construction of N-alkyl pyrrolidone and its derivatives in remarkable yields are obtained with operational comfort because of the milder reaction conditions. The PIL could be recycled up to five times without significant loss in its catalytic activity. The developed process is promising drop-in technology because of the reductive heterocyclisation of direct biomass derived LA to pyrrolidones.Graphic Abstract