The Preparation of Tritium and Deuterium-Labelled Camptothecin
The synthesis of d, l, ‐12‐bromocamptothecin (2d) from camptothecin (1) is described. Reduction of the bromo derivative 2d with tritium gas in the presence of palladium on carbon afforded d, l‐camptothecin 12‐3H having a specific activity of 29 Ci/mmol. A simpler labelling procedure was subsequently discovered whereby deuterium in the presence of palladium on carbon reduced ring B of camptothecin and also exchanged the C‐5 hydrogen with deuterium. The reduced camptothecin aromatized to camptothecin in the presence of air to give deuterium incorporation in the C‐5 and C‐7 positions.
Ronman, P. E., Wani, M., & Wall, M. (1981). The Preparation of Tritium and Deuterium-Labelled Camptothecin. Journal of Labelled Compounds and Radiopharmaceuticals, 18(3), 319-329. https://doi.org/10.1002/jlcr.2580180306