[en] N-Nitrosobis(2-oxopropyl)amine (BOP), a potent and selective pancreatic carcinogen in the Syrian golden hamster was synthesized with a ¹⁴C label in the alpha carbon. Oxidation of 2-hydroxypropyl-2-hydroxypropyl-1-¹⁴C-amine followed by nitrosation with sodium nitrite and hydrochloric acid gave radio-labeled BOP in 60% yield. (author)