The known 2-butyl-5-chloro-3-[2'-(tetrazol-5-yl)biphenyl-4-ylmethyl]-3H-imidazole-4-carboxaldehyde (I) was converted into the corresponding ethylene acetal (II) by treatment with ethylene glycol and trimethylchlorosilane in CH2Cl2. The title potassium salt was then obtained by treatment of an aqueous suspension of (II) with KOH, followed by freeze-drying.