Synthesis and preliminary pharmacological evaluation of 4'-arylalkyl analogues of clozapine. III. Replacement of the tricyclic nucleus with a bicyclic template

As a continuing part of our research program in search of novel compounds for the treatment of schizophrenia, we report the synthesis and preliminary receptor binding affinity for a series of bicyclic analogues of clozapine derived from a selection of promising tricyclic candidates published previously. These bicyclic compounds investigate some substituent effects and the length and nature of the linker between an ionizable nitrogen atom at physiological pH and the introduced aryl moiety. The chemistry, structural characterization, and in vitro evaluation are described. Preliminary findings on the effects on activity of the nature and length of the linker, degree of unsaturation, and selected substituents coupled to the bicyclic nucleus are discussed in relation to affinity for dopamine D-4 and serotonin 5-HT2A receptors.