Example 32
To a solution of compound 32-1 (650 mg, 1.44 mmol, 1 eq) in EtOH (2 mL) was added H2SO4 (1.20 g, 12.19 mmol, 0.65 mL, 8.47 eq) and sodium nitrite (298.1 mg, 4.32 mmol, 3 eq). The mixture was stirred at 60° C. for 2 hr. The reaction mixture was diluted with H2O (5 mL) and the mixture was extracted with EA (5 mL*3). The combined organic phase was washed with brine (5 mL*3), dried with anhydrous Na2SO4, filtered and concentrated in vacuum. The residue was purified by column chromatography (SiO2, Petroleum ether/Ethyl acetate=0/1 to 1:1) to give the crude product (180 mg, 0.30 mmol, 20.9% yield) as a white solid. 40 mg of the crude product were purified by prep-HPLC to give the title compound (26 mg) as white solid. LCMS (ESI): RT=0.949 min, mass calc. for C21H17BrF3NO 435.04, m/z found 437.7 [M+H]+; 1H NMR (400 MHz, DMSO-d6) δ 1.08-1.29 (m, 1H) 1.21 (d, J=6.53 Hz, 5H) 4.15 (dq, J=13.80, 6.69 Hz, 1H) 7.67-7.79 (m, 1H) 7.71 (d, J=2.01 Hz, 1H) 7.76 (d, J=8.53 Hz, 2H) 7.89-7.99 (m, 3H) 8.39-8.52 (m, 3H).
