Platinum on Carbon-Catalyzed H-D Exchange Reaction of Aromatic Nuclei due to Isopropyl Alcohol-Mediated Self-Activation of Platinum Metal in Deuterium Oxide

An efficient and simple deuteration method of arenes using the platinum on carbon-isopropyl alcohol-cyclohexane-deuterium oxide combination under hydrogen gas-free conditions was accomplished. Since the hydrogendeuterium exchange reaction cannot be promoted without isopropyl alcohol, zerovalent platinum metal (on carbon) is self-activated by the in situ-generated very low amount of hydrogen or hydrogendeuterium gas derived from isopropyl alcohol or isopropyl alcohol-d1. Deuterium-labeled compounds with high deuterium contents can be easily isolated by the filtration of platinum on carbon and simple extraction. The present hydrogen gas-free method is safe from the viewpoint of process chemistry and various arenes possessing a variety of reducible functionalities within the molecule could be effectively and directly deuterium-labeled without undesired reduction.