Facile Hydrogenative Deprotection of N‑Benzyl Groups Using a Mixed Catalyst of Palladium and Niobic Acid-on-Carbon

The palladium-on-carbon (Pd/C)-catalyzed hydrogenative deprotection of the N-benzyl-protecting group was effectively facilitated by the combined use of niobic acid-on-carbon (Nb₂O₅/C). Nb₂O₅/C is an acidic heterogeneous catalyst prepared from NbCl₅ and activated carbon. The catalysts were easily removed from the reaction mixture and reusable. Deprotected amines were obtained in excellent yields without an additional neutralization process. The facilitating effect of Nb₂O₅/C was also observed during the Pd/C-catalyzed hydrogenative deprotection of the N-benzyloxycarbonyl (Cbz) and O-benzyl groups.