Concentrated hydrobromic acid (24.8 μL) was added to a solution of (8S)-2-{(E)-2-[6-methoxy-5-(4-methyl-1H-imidazol-1-yl)pyridin-2-yl]vinyl}-8-(2-trifluoromethylphenyl)-5,6,7,8-tetrahydro-[1,2,4]triazolo[1,5-a]pyridine (51.42 mg) in ethanol (1 mL), and 1 mL of heptane was added with stirring at room temperature. After several minutes, 1 mL of heptane was further added to the solution and stirring was continued. The solution was stirred at room temperature for one hour and then further stirred at about 5° C. for 20 minutes. The precipitated solid was collected by filtration through a glass filter and dried under reduced pressure at room temperature to obtain 49.24 mg of the title compound as white solid crystals.
