Pyrrolodiazepines

Premazepam is a drug in the pyrrolodiazepine class. It is a partial agonist of benzodiazepine receptors and was shown in 1984 to possess both anxiolytic and sedative properties in humans but was never marketed.

Azepindole (McN-2453) is a tricyclic compound with antidepressant and antihypertensive effects that was developed in the late 1960s but was never marketed.