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

The palladium-on-carbon (Pd/C)-catalyzed hydrogenative deprotection of the -benzyl-protecting group was effectively facilitated by the combined use of niobic acid-on-carbon (NbO/C). NbO/C is an acidic heterogeneous catalyst prepared from NbCl 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 NbO/C was also observed during the Pd/C-catalyzed hydrogenative deprotection of the -benzyloxycarbonyl (Cbz) and -benzyl groups.