The addition of methyl magnesium iodide to 2-acetylthiophene (I) and subsequent reduction of the propenyl derivative (II) with H2 over Pd/C in methanol yields the 2-isopropylthiophene (III), which is acetylated with acetyl chloride. Reduction of 2-isopropyl-5-acetylthiophene (IV) with lithium aluminum hydride gives the corresponding alcohol, which is converted to the triphenylphosphonium salt (V). By Wittig reaction with 4-ethoxycarbonyl benzaldehyde (VI) the ethyl ester obtained is then hydrolyzed with potassium hydroxide to yield the free acid.