A highly efficient Pd–C catalytic hydrogenation of pyridine nucleus under mild conditions

A synergistic Pd–C catalytic hydrogenation of 4-pyridinecarboxamides straightforward to 4-piperidinecarboxamide hydrochlorides was developed in the presence of ClCH2CHCl2. It provided a novel strategy for highly efficient hydrogenation of pyridine nuclear by using low-cost Pd–C catalyst under mild conditions.