Pyrrolo[1',2':1,2]imidazo[4,5-b]pyridines, pyrrolo- [2',1':2,3]imidazo[4,5-c]pyridines and pyrrolo[2,1-f]purines as potential benzodiazepine ligands.

The synthesis of some 7,8,8a,9-tetrahydro-6H-pyrrolo[1',2':1,2]imidazo[4,5-b]pyridin-6-ones, 5,5a,6,7-tetrahydro-8H-pyrrolo[2',1':2,3]imidazo[4,5-c]pyridin-8-ones and 7,8,8a,9-tetrahydro-6H-pyrrolo[2,1-f]purin-6-ones is reported. The structure of the obtained compounds has been assigned by means of 1H-NMR spectra assisted by NOESY measurements. In addition, the ability to displace [3H]-flunitrazepam binding from rat brain membranes is determined. Only the pyrrolopurine derivative 5d binds to the benzodiazepine receptor (BZR) with appreciable potency.