2-Phenylpyrroles as conformationally restricted benzamide analogues. A new class of potential antipsychotics. 2.

A series of 2-phenylpyrrole Mannich bases was synthesized and screened in pharmacological models for antipsychotic activity and extrapyramidal effects. Structure modifications of 5-(4-fluorophenyl)-2-[[4-(2-methoxyphenyl)-1-piperazinyl]methyl]pyrrole (1), the prototype of a new class of sodium-independent atypical dopamine D-2 antagonists, resulted in 2-[[4-(7-benzofuranyl)-1-piperazinyl]methyl]-5-(4-fluorophenyl)pyrrole (15), which was an even more potent and selective D-2 antagonist than the parent compound. The excellent oral activity in the apomorphine-induced climbing behavior and the conditioned avoidance response tests and the absence of catalepsy make this compound particularly promising as a potential antipsychotic with a low propensity to induce acute extrapyramidal side effects.