Benzylpiperazine derivatives. IV. Syntheses and cerebral vasodilating activities of 1-benzyl-4-diphenylmethylpiperazine derivatives.

A considerable body of literature exists on the biological activity of compounds containing the piperazine moiety. In the field of 1-benzyl-4-diphenylmethylpiperazines, antihistaminics,2-4) tranquillizers,5,6) and vasodilators7) have been reported. Some of them, such as buclizine (1), meclizine (2) and medibazine (3), have been used clinically. More recently, 1-diphenylmethyl-4-(4-hydroxybenzyl)piperazines (4) were disclosed to be useful in the treatment of disturbance of cerebral blood flow.8) In the course of our studies aimed at finding novel cerebral vasodilators,9) 1diphenylmethy1-4-(2,3,4-trimethoxybenzyl)piperazine (5) was found to possess considerable activity. This compound was described in the patent literature but nothing about its medical