The general procedure for the synthesis of 2-amino-5-chloro-2,6-difluorobenzophenone using [4-chloro-2-(2,6-difluorobenzyl)phenyl]-carbamic acid-1,1-dimethylethyl ester as a starting material was as follows: the N-Boc-protected aminobenzophenone was dissolved in anhydrous dichloromethane (50 mL), followed by the addition of trifluoroacetic acid (50 mL). The reaction mixture was stirred for 1 h at room temperature and then the solvent was evaporated to dryness by rotary evaporator under vacuum. The resulting residue was dissolved in a mixture of ethyl acetate (100 mL) and saturated aqueous sodium bicarbonate (100 mL). The organic phase was separated and washed with saturated aqueous sodium bicarbonate solution and subsequently dried with anhydrous magnesium sulfate. The dried organic phase was concentrated to dryness by rotary evaporator and the target product 2-amino-5-chloro-2,6-difluorobenzophenone was quantitatively obtained, and mass spectrometry analysis showed m/z = 268 (M + H).
