4-Aminopyridine derivatives with antiamnesic activity.

Acetylcholine (Ach) enhancement, useful in the treatment of Alzheimer's disease (AD), may be obtained by means of ion channel modulators such as 4-aminopyridine (4-AP). 4-AP is also the central ring of tacrine, the first drug approved for the treatment of AD. The synthesis and pharmacological activity of three 4-AP derivatives, prepared with the aim of improving their antiamnesic activity, is here described. In two of these compounds 4-AP is connected to 4-aminobutyric acid (GABA), whereas in the third it is connected to 2-indolinone, i.e., the skeleton of linopirdine, another Ach enhancing agent. The new compounds showed potent antiamnesic activity in comparison with piracetam.