A mixture of 4-[2-(4-Fluoro-3-trifluoromethyl-phenyl)-2-oxo-ethylcarbamoyl]-piperidine-1-carboxylic acid tert-butyl ester (2900.00 mg; 6.71 mmol; 1.00 eq.), triethylamine (0.94 ml; 6.71 mmol; 1.00 eq.), and ammonium acetate (3618.76 mg; 46.95 mmol; 7.00 eq.) in 20 ml of n-butanol was placed in microwave (150° C.) for 20 min. after cooling to rt, the reaction mixture was diluted with 150 ml of ethyl acetate and washed with water, 5% NaHCO3aq, then brine and concentrated. The residue was treated with ether and collected whit solid as title compound (1500 mg, 54% yield).
