Abstract
Synthesis of 2H3‐lorazepam was achieved by modification of literature procedures for the unlabelled drug. The key step in the seven step procedure was the initial one where upon selective exchange of 2‐amino‐5,2′‐dichloro‐benzophenone was obtained in deuterated acids. Purifications were carried out by preparative HPLC. The 2H3‐lorazepam is suitable for use as an internal standard in GC‐MS‐NICI‐SIM quantitative analysis in forensic case work.