A mixture of 2-(4-acetyl-3-hydroxy-2-propylphenoxy)ethyl bromide (2.71 g), ethyl 2 mercaptobenzimidazole-5-carboxylate (2.00 g) and anhydrous potassium carbonate (1.49 g) in N,N-dimethylformamide (30 ml) was stirred at 80-90 ° C. for 30 minutes. The reaction mixture was poured into ice-water, made acidic with concentrated hydrochloric acid and extracted with ethyl acetate. The organic layer was washed with water, dried over anhydrous sodium sulfate and evaporated. The resulting residue was purified by silica gel column chromatography, eluting with dichloro-methane-ethyl acetate (10:1), to give ethyl 2-[2-(4-acetyl-3- hydroxy-2-propylphenoxy)ethylthio]benzimidazole-5-carboxylate (2.33 g, 58.5 %) as a yellow oil.
