N-substituted (2,3-dihydro-1,4-benzodioxin-2-yl)methylamine derivatives as D2 antagonists/5-HT1A partial agonists with potential as atypical antipsychotic agents

A series of N-substituted 1-(2,3-dihydro-1,4-benzodioxin-2-yl)methylamine derivatives with D-2 antagonist/5-HT1A partial agonist activity has been prepared as potential atypical antipsychotic agents. Optimization of in vitro receptor binding activity and in vivo activity in rodent models of psychosis has led to compound 24, which showed good affinities for human D-2, D-3, and 5-HT1A receptors but significantly less affinity for human alpha(1) adrenoceptors and rat H-1 and muscarinic receptors. In rodents, 24 showed functional D-2-like antagonism and 5-HT1A partial agonism. After oral dosing, 24 showed good activity in rodent antipsychotic tests and very little potential to cause extrapyramidal side effects (EPS), as measured by its ability to induce catalepsy in rats only at very high doses. In the light of this promising profile of activity, 24 has been selected for clinical investigation as a novel antipsychotic agent with a predicted low propensity to cause EPS.