Synthesis of (R)‐(+)‐3H‐etomidate

Abstract Etomidate, (R)‐(+)‐ethyl‐1‐(1‐phenylethyl)‐1 H ‐imidazole‐5‐carboxylate, is a short‐acting hypnotic. A new synthesis, featuring optical resolution on a non‐radioactive precursor and introduction of the tritium label by reductive dehalogenation, is described. The title compound was obtained at a specific activity of 3.77. Ci/mmol and a 99.9 % HPLC purity.