Hydrochloric Acid → 4-[5-(1-piperazinylmethyl)-1H-tetrazol-1-yl]-2-(trifluoromethyl)benzonitrile

To a solution of 1,1-dimethylethyl 4-({1-[4-cyano-3-(trifluoromethyl)phenyl]-1H-tetrazol-5-yl}methyl)-1-piperazinecarboxylate (Intermediate 25, 532 mg, 1.22 mmol) in methanol (8 mL) was added hydrochloric acid in dioxane (5 mL, 20.0 mmol). The reaction mixture was stirred at room temperature for 1 h. The mixture was concentrated, the white solid was dissolved in methanol and poured onto a 5 g SCX cartridge, washed with methanol (2 CV) and eluted with 10% ammonia) in methanol (2 CV). The ammonia in methanol fraction was concentrated under vacuum to leave a white solid, 4-[5-(1-piperazinylmethyl)-1H-tetrazol-1-yl]-2-(trifluoromethyl)benzonitrile (402 mg).