Hydrochloric Acid → (3-(Tert-butyldimethylsilyloxy)-4-fluorophenyl)(3-fluoro-5-(1,1,2,2-tetrafluoroethoxy)phenyl)methanone

At −78° C. under argon, to a solution of 1-bromo-3-fluoro-5-(1,1,2,2-tetrafluoroethoxy)benzene (2.04 g, 7.01 mmol) in anhydrous ether (20 mL) was added nBuLi (3.5 mL, 2.0 M in cyclohexane, 7.0 mmol) dropwise and the reaction mixture was stirred for 1 h. 3-(Tert-butyldimethylsilyloxy)-4-fluoro-N-methoxy-N-methylbenzamide (2.00 g, 6.38 mmol) was added in one portion and the reaction mixture was stirred at −78° C. for 1.5 h. The pale yellow solution was poured into a 1 N HCl aqueous solution (30 mL) and ether (30 mL) was used to rinse the reaction flask. The aqueous phase was separated and extracted with diethyl ether (20 mL). The combined ether portions were dried over Na2SO4, filtered and concentrated. The resulting oil was purified by ISCO chromatography (120 g column) using hexanes/EtOAc (0-100% over 30 min) to give (3-(tert-butyldimethylsilyloxy)-4-fluorophenyl)(3-fluoro-5-(1,1,2,2-tetrafluoroethoxy)phenyl)methanone at a retention time of 7 min (2.11 g, 71% yield). LCMS: RT=2.41 min [M+H] 465.19 (Phenomenex Luna C18 column, 4.6×30 mm eluting with 10-90% MeOH/H2O over 2 minutes containing 0.1% TFA; 5 mL/min, monitoring at 220 nm); NMR: 400 MHz 1H (CDCl3) 7.33 ppm, 3H, m; 7.28 ppm, 1H, m; 7.11 ppm, 2H, m; 5.86 ppm, 1H, t, J=53.39 Hz; 0.95 ppm, 9H, s; 0.15 ppm, 6H, s.

1. stirringthe reaction mixture was stirred at −78° C. for 1.5 h
2. washto rinse the reaction flask
3. customThe aqueous phase was separated
4. extractionextracted with diethyl ether (20 mL)
5. dry with materialThe combined ether portions were dried over Na2SO4
6. filtrationfiltered
7. concentrationconcentrated
8. customThe resulting oil was purified by ISCO chromatography (120 g column)
9. customhexanes/EtOAc (0-100% over 30 min)

ORD record

ord-5557b6f2e307402ea974a487932ffb36

Source dataset

uspto-grants-2014_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08642576B2