Trifluoroacetic anhydride → Tert-butyl 4-(3-cyano-1-(4-(methylsulfonyl)phenyl)-6-oxo-1,6-dihydropyridazin-4-yloxy)piperidine-1-carboxylate

Participants

Reaction Steps

To a stirring solution of tert-butyl 4-(3-carbamoyl-1-(4-(methylsulfonyl)phenyl)-6-oxo-1,6-dihydropyridazin-4-yloxy)piperidine-1-carboxylate (985 mg, 2.0 mmol) in THF (50 mL) at room temperature under argon was added TEA (405 mg, 4.0 mmol), and was followed by addition of TFAA (840 mg, 4.0 mmol). The resulting reaction mixture was stirred at room temperature overnight. The solvent was removed in vacuo. The crude product was dissolved in a small amount of DCM (˜5 ml) and loaded onto a 40 g ISCO silica gel column which was eluted with a 20 min gradient from 20% to 100% EtOAc/Hexanes. 908 mg (91%) of tert-butyl 4-(3-cyano-1-(4-(methylsulfonyl)phenyl)-6-oxo-1,6-dihydropyridazin-4-yloxy)piperidine-1-carboxylate was obtained as a white solid. 1H NMR (400 MHz, CDCl3) δ ppm 1.43-1.51 (m, 9H) 1.81-1.95 (m, 2H) 1.95-2.09 (m, 2H) 3.27-3.57 (m, 2H) 3.57-3.88 (m, 2H) 4.38-4.81 (m, 1H) 6.29 (s, 1H) 7.83 (d, J=8.35 Hz, 1H) 8.20 (dd, J=8.57, 2.42 Hz, 1H) 9.04 (d, J=2.64 Hz, 1H). MS (ESI) 419 (M+H-tBu).

Provenance & Evidence