[Synthesis of leonurine and syringic acid aminoesters].

In this paper, the synthesis of leonurine (Ⅰ) and a series of syringic acid aminoesters (Ⅲ_(1～12), Ⅳ_(1～8)) is reported.These compounds showed inhibitory activity against rat platelet aggregation induced by adenosine diphosphate or collagen in vitro. Compounds Ⅲ_1, Ⅲ_5 and Ⅳ_8 were more effective than leonurine. But, δ-guanidino-butanol-1(11) and syringic acid showed little activity.