Potential neuroleptic agents. 2,6-Dialkoxybenzamide derivatives with potent dopamine receptor blocking activities

A series of some novel N-(l-ethyl-2-pyrrolidinylmethyl)benzamides was synthesized and tested for dopamine receptor blockade in vivo by the ability to block the apomorphine syndrome in the rat. Several compounds were considerably more potent than sulpiride as dopamine receptor blockers and displayed low liability to induce extrapyramidal side effects (catalepsy) in the rat. The blockade of dopamine receptor activity in vivo was mainly confined to the levorotatory isomers having the S absolute configuration. The structure-activity relationships are discussed.