Facile synthesis of novel tacrine analogues

The synthesis of highly potent and selective acetylcholinesterase inhibitors, tacrine analogues with the structure of fused 4-aminoquinolines and 4-aminopyridines, has been accomplished by direct cyclocondensation of 1-aryl-4-cyano-5-aminopyrazoles with cyclic ketones using tin(IV) chloride as catalyst.