Benzylpiperazine Derivatives. VI. Design and Syntheses of Vinylogs of 1-Benzyl-4-diphenylmethylpiperazine Derivatives and Their Cerebral Vasodilating Activities

As a lead development based on the previous quantitative structure-activity relationship (QSAR) results on cerebral vasodilating activities of 1-benzyl-4-diphenylmethylpiperazines, 1- cinnamyl-4-diphenylmethylpiperazines having electron-donating groups on the cinnamyl moiety were designed. Two methods of synthesis were developed. As expected from the QSAR results, these compounds exhibited stronger potency and longer-lasting effect than cinnarizine and flunarizine.