Carbonic acid, bis(1,1-dimethylethyl) ester → HCID 67389163, compound

Participants

Reaction Conditions

Reaction Steps

N,N-dimethylpyridin-4-amine (0.190 g), was added to a stirred suspension of 5-bromo-3-(4-fluoro-1,3-benzoxazol-2-yl)pyridin-2-amine (2.4 g) and di-tert-butyl carbonate (4.83 g) in DMF (50 ml) at 25° C. under nitrogen. The resulting suspension was stirred at 25° C. for 45 hours. The DMF was evaporated under reduce pressure. The mixture was adsorbed on silica gel. The crude product was purified by flash chromatography on silica gel eluting with 0 to 2% methanol in dichloromethane. The solvent was evaporated to dryness to afford tert-butyl N-[5-bromo-3-(4-fluoro-1,3-benzoxazol-2-yl)-2-pyridyl]-N-tert-butoxycarbonyl-carbamate (3.54 g, 89%) as a pale orange solid. NMR Spectrum: (CDCl3) 1.36 (s, 18H), 7.12 (dd, 1H), 7.38 (ddd, 1H), 7.42 (d, 1H), 8.72 (d, 1H), 8.85 (d, 1H); Mass spectrum: M+H+ 508-510 PdCl2dppf (0.278 g), potassium acetate (2.095 ml) and 4,4,5,5-tetramethyl-2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1,3,2-dioxaborolane (1.923 g) were added over a period of 10 minutes, to a stirred solution tert-butyl N-[5-bromo-3-(4-fluoro-1,3-benzoxazol-2-yl)-2-pyridyl]-N-tert-butoxycarbonyl-carbamate (3.5 g) dissolved in dioxane (30 ml) degazed and under argon. The resulting mixture was stirred at 80° C. for 3 hours. The salts were filtered; The mixture was evaporated under reduce pressure. The crude product was purified by flash chromatography on silica gel eluting with 30 to 40% ethyl acetate in petroleum ether. The solvent was evaporated to dryness to afford tert-butyl N-tert-butoxycarbonyl-N-[3-(4-fluoro-1,3-benzoxazol-2-yl)-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-2-pyridyl]carbamate (3.26 g) as a pale orange solid. NMR Spectrum: (CDCl3) 1.33 (s, 18H), 1.39 (s, 12H), 7.10 (dd, 1H), 7.34 (ddd, 1H), 7.42 (d, 1H), 8.99 (d, 1H), 9.08 (d, 1H); Mass spectrum: M-(boc+pinacol)+H+ 374

Provenance & Evidence