Synthesis and anticonvulsant activity of 1-substitued benzyl5-phenyl-3-pyrazolidinones

OBJECTIVE To quantitate the structure-activity relationship(SAR) of 1-substituted benzyl-5-phenyl-3-pyrazolidone derivatives. METHODS Starting from ethyl cinnamate,ring-closing with hydrazine hydrate to gain 5-phenyl-3-pyrazolidone derivatives,then condensation and reduction to gain 1-substituted benzyl-5-phenyl-3-pyrazolidone derivatives.All the compounds were evaluated the anticonvulsant potency by maximal electroshock test. RESULTS All compounds had anticonvulsant activity in some extent,in which,non-substituted benzyl compound 1-benzyl-5-phenyl-3-pyrazolidone(2 a) was more active than other compounds. CONCLUSION Benzyl at the first position increases anticonvulsant activity of 5-phenyl-3-pyrazolidone compound.