Valproic acid finds clinical use as an anticonvulsant and mood-stabilizing drug that has proven useful in the treatment of epilepsy, bipolar disorder, and other conditions. The structure of valproic acid is shown in (iii) . Identify the constitutional isomer(s) of valproic acid from the given structures: (i) (ii) (iii) (Valproic acid)

Step-by-step solution

The structure of valproic acid given in (iii) is 2-propylpentanoic acid. Its molecular formula is C₈H₁₆O₂ . Structure (i) represents the exact same molecule, 2-propylpentanoic acid, just drawn with a different visual representation of the propyl chains. Since it is identical to valproic acid, it is not considered a constitutional isomer. Structure (ii) represents 2-ethylhexanoic acid. It has the same molecular formula, C₈H₁₆O₂ , but a different connectivity of atoms (an ethyl group and a butyl group attached to the