870787-06-7

870787-05-6

870787-06-7

Example 16. Preparation of 3-(trifluoromethyl)pyrazine-2-carboxylic acid (Compound No. 3-5) Methyl 3-(trifluoromethyl)pyrazine-2-carboxylate (700 mg, 3.4 mmol) was dissolved in a solvent mixture of ethanol-water (1:1, 10 mL, v/v), followed by addition of potassium hydroxide (300 mg). The reaction mixture was heated to reflux for 1 hour. Upon completion of the reaction, the reaction solution was concentrated under reduced pressure and the residue was diluted with water and washed with ethyl acetate. The aqueous phase was acidified with hydrochloric acid and extracted with ethyl acetate and the organic phase was washed with saturated brine. The combined organic phases were dried with anhydrous magnesium sulfate and concentrated under reduced pressure to give 409 mg of target compound crystals in 63% yield. Properties: melting point 130-134°C.