Synthesis of 2,3,4,4a,5,9b-hexahydro-1H-pyrido[4,3-b]indole derivatives and their central nervous system activities.

The synthesis and some pharmacological effects of cis- and trans-2-substituted 2,3,4,4a,5,9b-hexahydro-1H-pyrido[4,3-b]indole derivatives are described. In these derivatives, the substituents of the 2, 5 and 8 position, together with the relative configuration of the 4a and 9b position, influenced the potency of the central nervous system activities. A cis-2-[3-(p-fluorobenzoyl)propyl] analogue (5k) of carbidine (1) possessed not only thymoleptic-like biological activity but had more potent neuroleptic activity than the parent drug.