Potential Anxiolytic agents.: Part 4:: Novel orally-active N5-substituted pyridol[1,2-a]benzimidazoles with high GABA-A receptor affinity

A series of pyrido[1,2-a]benzimidazoles (PBIs) with substitution on the N-5-nitrogen has been synthesized and found to possess high affinity for the benzodiazepine (BZD) site on the GABA-A receptor. The compounds evaluated include those bearing a heteroalkyl group and heterocyclic rings. The most promising of these compounds is ethoxymethyl analogue 24, which has an IC50 of 0.1 nM for the BZD site on the GABA-A receptor and has been advanced to human clinical trials. (C) 2002 Elsevier Science Ltd. All rights reserved.