Synthesis of Deuterium-Labelled Salicylcarnosine

Abstract

Effect of temperature on the efficiency of deuterium introduction into a new biologically active compound salicylcarnosine (SC) has been studied. Gaseous deuterium and heavy water were used as deuterium sources. The synthesis of labelled SC by a solid-phase method at 190°C leads to formation of [D]SC in 53% yield and deuterium content about 4.8 atoms per molecule. It has been shown that isotope exchange between SC protons and deuterium water proceeds more efficiently after preliminary treatment of catalyst with gaseous deuterium at ambient temperature. [D]SC forms in 46% yield and contains about 7.3 deuterium atoms per molecule. The preparative synthesis of labelled SC by this procedure at 190°C results in [D]SC yield of 60–70% at deuterium content about 6.2 atoms per molecule. The new procedure for the activation of deuterium inclusion in peptides opens additional opportunities for preparing highly labelled compounds.