Synthesis and binding affinity of 2,3,3a,4,9,9a-hexahydro-9,4-(iminomethano)-1H-benz[f]indenes. Ligands for the PCP site of the NMDA receptor

A series of 2,3,3a,4,9,9a-hexahydro-9,4-(iminomethano)-1H-benz[f]indenes was prepared and their ability to displace [3H]TCP was measured. The 5-amino derivatives 5 and 12b were the most potent members of this series with Ki values of 14 nM and 8 nM respectively. The orientation of the cyclopentane ring was crucial for binding potency, with the endo isomer 12a>10 times more potent than the exo-isomer 13.