Deuterated Oxytocins: The Synthesis and Biological Properties of a Crystalline Analog of Deamino-oxytocin Deuterated in the 5-asparagine Position

This paper describes the synthesis and biological activity of [5-L-asparagine-α ,β ,β -d3]-deamino-oxytocin. The model peptide S-benzyl-β -mercaptopropionyl-L-asparaginyl-α ,β ,β -d3-glycinamide was also prepared to observe the effect of the conditions of peptide synthesis on the deuterium content. It was found that normal synthetic procedures could be used without a significant loss in the deuterium content. The [5-L-asparagine-α ,β ,β -d3]-deamino-oxytocin had, within experimental error, the same avian vasodepressor and oxytocic activities as deamino-oxytocin itself.