Ynthesis of 6-piperazinyl-3,4-dihydroquinazolin-2(1H)-ones

A series of new 6-piperazinyl-3,4-dihydroquinazolin-2(1H)-ones have been synthesized. The described compounds are structurally related to adoprazine, a potential atypical antipsychotics bearing potent D2 receptor antagonist and 5-HT1A receptor agonist properties. Buchwald- Hartwig coupling of suitably modified aryl bromides with tert-butyl piperazine-1-carboxylate afforded the advanced intermediate piperazinyl-3,4-dihydroquinazolin-2(1H)-one. The reductive amination of the latter with appropriately designed biarylaldehydes accomplished the synthesis of 6-piperazinyl-3,4-dihydroquinazolin-2(1H)-ones.