1-Propylbutylphosphinic acid 2,(1-propylbutyl) methylphosphinic acid 3 and 1- propylbutylphosphonic acid 4 have been synthesized as bioisosteres of the corresponding carboxylic acid valproate 1, which is a potent anticonvulsant. The novel phosphinic and phosphonic acids were tested for their anticonvulsant activity and were found to be inactive.
