Thus, based on inspection of the docking data, the 4-atom-long linkers seem to be more optimal for targeting LmPTR1, due to the stacking interactions with His241, and the Ncyclopropyl substituent of 1b, 1c and 1d makes stabilizing interactions with both LmPTR1 and TbPTR1. Therefore, the docking poses indicate that some of the selected compounds may have dual-PTR1-targeting potential. Synthesis of designed compounds. The benzothiazoles of series 1 and series 2 (discussed later) were synthesized as follows. The 6-amide derivatives1a, 1b, 1c, 1e, 2a, 2b, 2c, 2d, 2e, 2f and 2g were obtained by coupling commercially available 2-aminobenzothiazole-6-carboxylic acid with the appropriate amines (3a-3k) under standard conditions (using EDC and HOBt in DMF at room temperature, overnight) (Scheme 1). The activities and toxicities for series-1 compounds pinpoint lead scaffolds for further anti-trypanosomatid drug design. The inhibitory activities against TbPTR1, LmPTR1, T. brucei, and L. infantum, as well as the cytotoxic concentration for THP-1 cells were measured for the differently linked compounds (Tab. It is worth noting that the 1b scaffold is shared with 1c which, unlike the other compounds, also shows some activity against L. infantum (24%). However, 1c has distinctly lower activity against LmPTR1 than 1b (72% and 26%, respectively). Overall, this suggests that the unusual activities of the N-cyclopropyl-substituted compounds against L. infantum parasites may be due to mechanisms other than targeting PTR1, which could be, e.g., related