Compounds 5d, 5e and 5f show an improved percentage of T. brucei inhibition at 10 μM, in line with their selection for synthesis being motivated by altered marker properties (Figure ). For these compounds, EC 50 values were determined, see Table . Indeed, the more lipophilic compounds were found to have low micromolar EC50s against T. brucei brucei, with 5d being the best (EC50 0.66 ± 0.48 μM), and they have SIs of 3-38 based on their cytotoxicity on THP-1 derived macrophages.