Pyridine → 6-(trifluoromethyl)-2,4-dihydro-1H-3,1-benzoxazine-2,4-dione

Participants

Reaction Conditions

Reaction Steps

To a suspension of 2-amino-5-(trifluoromethyl)benzoic acid (2 g, 9.75 mmol) in acetonitrile (10.0 ml) was added pyridine (2.31 g, 2.37 ml, 29.2 mmol) and a solution of triphosgene (1.74 g, 5.85 mmol) in acetonitrile (10.0 ml) at 50° C. The reaction mixture was stirred for 2 h at 50° C. Then additional triphosgene (579 mg, 1.95 mmol) was added and heating to 50° C. was continued overnight. The solvent was removed and water was added. The mixture was extracted with EtOAc and the combined extracts were washed with water and brine, dried with Na2SO4 and evaporated. The remaining residue was triturated in dichloromethane for 3 h. The solid was filtrated off and washed two times with dichloromethane to afford the crude title compound (1.53 g, 45%) as off-white solid. MS (ESI): 230.3 (M−H)+.

Provenance & Evidence