Synthesis of deuterium and tritium labelled derivatives of maleopimaric acid

Abstract

Abstract A new hepatoprotective agent, N‐(2‐hydroxyethyl)‐maleopimarimidyl morpholide (RU18492) has been synthesised labelled with tritium at C‐3, C‐4a, C‐10 and in the C‐isopropyl group. The incorporation of tritium relies on the acid‐catalysed isomerisation of levopimaric acid (4) to abietic acid (2), which was then converted in three stages to (3).