1-(7-Bromo-3,4-dihydro-1H-isoquinolin-2-yl)-2,2,2-trifluoroethanone

17680-55-6

407-25-0

181514-35-2

General procedure for the synthesis of N-trifluoroacetyl-7-bromo-1,2,3,4-tetrahydroisoquinoline from 7-bromo-1,2,3,4-tetrahydroisoquinoline and trifluoroacetic anhydride: pyridine (3.79 mL, 47.1 mmol) and 4-N,N-dimethylaminopyridine (58.0 mg, 0.471 mmol) were added sequentially to a solution of chloroform (80 mL) of 7-bromo-1,2,. 3,4-tetrahydroisoquinoline (5.00 g, 23.6 mmol) to a solution of chloroform (80 mL). Subsequently, trifluoroacetic anhydride (3.59 mL, 25.9 mmol) was added slowly and dropwise. The reaction mixture was gradually warmed to room temperature and stirred continuously for 14 hours. Upon completion of the reaction, the solvent was removed by concentration under reduced pressure and the resulting residue was diluted with ethyl acetate. The organic phase was washed with 1 mol/L hydrochloric acid, saturated aqueous sodium bicarbonate and brine, dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The residue was purified by silica gel column chromatography with 10% to 25% ethyl acetate/hexane as eluent to afford the target product N-trifluoroacetyl-7-bromo-1,2,3,4-tetrahydroisoquinoline (6.97 g, 96% yield) as a pale yellow oil. The product was structurally confirmed by nuclear magnetic resonance hydrogen (1H NMR, 600 MHz, CDCl3) and carbon (13C NMR, 151 MHz, CDCl3) spectra as well as high-resolution mass spectrometry (HRMS-EI).