Structure-activity relationships of acetylcholinesterase noncovalent inhibitors based on a polyamine backbone. 4. Further investigation on the inner spacer.

Novel multi-target-directed ligands were designed by replacing the inner dipiperidino function of 3 with less flexible or completely rigid moieties to obtain compounds endowed with multiple biological properties that might be relevant to Alzheimer's disease. 15 was the most interesting, inhibiting AChE in the nanomolar range and inhibiting AChE-induced and self-promoted beta-amyloid aggregation in the micromolar range.