Ecofriendly Reductive Amination of a Levulinic Acid\nPlatform Molecule for the Synthesis of 5‑Methyl‑<i>N</i>‑Aryl-Pyrrolidones Exploiting Formic Acid as an\nLOHC

The\nunsustainable exploitation of fossil feedstocks for energy\nand chemical production has led, in the past few years, to the modern\nenergy and environmental crisis, thus stimulating increased awareness\nin the definition of more sustainable alternatives. Among the transformations\nof biomass-derived levulinic acid, recognized as one of the top 10\nplatform molecules, the production of 5-methylpyrrolidinones is of\ngreat importance in diverse industrial fields. In this work, we defined\na waste-minimized protocol for the production of <i>N</i>-aryl 5-methylpyrrolidinones, aiming both at the synergistic employment\nof a benign H-source and reaction media and at the optimization of\nthe workup and purification step. The choice of formic acid as the\nhydrogen carrier and water as the solvent was beneficial for the replacement\nof gaseous hydrogen typically used in the synthesis of <i>N</i>-aryl 5-methylpyrrolidinones. Moreover, the safety and economic advantages\nof formic acid as a benign LOHC for this transformation were further\nconfirmed by a comparison, with other H-sources, of the Ecoscale penalty\npoints. The optimized extraction workup protocol allowed an E-factor\nreduction of 63% compared to a simple filtration for purification\nmethod. To further evidence the environmental improvement, Ecoscale\nwas exploited, highlighting the benefits of our process in comparison\nto available literature protocols.