Spiro [4.5] decane-2-carboxylic acid (12a), spiro [4.5] decane-2, 2-dicarboxylic acid (1 la), spiro [4.6] undecane-2-carboxylic acid (12b), spiro [4.6] undecane-2, 2-dicarboxylic acid (llb), and spiro [4.6] undecane-2-acetic acid (13) were synthesized by an improved method and evaluated for anticonvulsant activity. These analogues were synthesized to evaluate the role of the carboxylic acid group as an essential substituent in valproic acid (di-n- ...