Biologically active compounds, incorporating the 2-acylazetidine moiety, include natural products such as alkaloids found in the genus Daphniphyllum (Kobayashi and Kubota, 2009) as well as 2-aroylazetidines known as potent inhibitors of dipeptidyl peptidase IV (DPP-IV) (Ferraris et al., 2004), a proline-specific serine protease used as target in several therapeutic areas such as diabetes (Weber, 2004) pain (Ronai et al., 1999), and cognition enhancement (During et al., 2003; Figure 1). The gene discussed is DPP4; the disease is diabetes mellitus.