Effect of Temperature during Preactivation of 5% Pd/C and 5% Pd/AlO with Deuterium Gas on Isotope Exchange between Deuterium Water and an Organic Compound

It was demonstrated by the example of serotonin, 3-(N-pyrrolyl)propanoyl-L-histidine, sodium p-phenylbenzoate, and Pro–Gly–Pro that activation of isotope exchange with DO also occurred when a solution of an organic compound in DO was mixed with 5% Pd/AlO or 5% Pd/C (after preliminary treatment of catalysts with deuterium gas on heating). When implementing this technique, 2–3 atoms of deuterium were incorporated in serotonin, 4–5 atoms, in Pro–Gly–Pro, 7–8 atoms, in 3-(N-pyrrolyl)propanoyl-L-histidine, and 3–4 atoms, in sodium p-phenylbenzoate. In the latter case, as judged from the composition of the reaction products, atomic deuterium takes part in the activation of isotope exchange with DO. The participation of atomic deuterium in these reactions follows from the intensification of the degradation of the compounds during deuteration. When using compounds that do not contain labile fragments, isotope exchange with DO can be activated by keeping the catalyst at room temperature and heating.