A series of analogues based on the anticonvulsant carbetapentane (1, 2-[2-(diethylamino)ethoxy]ethyl 1-phenyl-1-cyclopentylcarboxylate) was prepared as potential novel anticonvulsant drugs. Structure-activity relationships of analogues in which the ester function and cyclopentane moieties were modified have been investigated by evaluating their ability to prevent seizures in the rat maximal electroshock test. These compounds (11, ED50 = 16 mumol/kg; 12, ED50 = 86 mumol/kg, and 23, ED50 = 173 mumol/kg) were effective anticonvulsants. Compound 11, an alkyl ether derivative of 1, was more potent than the parent compound (ED50 = 48 mumol/kg) and also showed a 2-fold increase in potency compared to that of the prototypic anticonvulsant drug diphenylhydantoin.