Dimethylformamide → Di-tert-butyl [4-[[2-(4-fluoro-2-methyl-phenoxy)-5-(trifluoromethyl)benzoyl]amino]-2-oxo-1-pyridyl]methyl phosphate

Participants

Reaction Steps

To a solution of 2-(4-fluoro-2-methyl-phenoxy)-N-(2-oxo-1H-pyridin-4-yl)-5-(trifluoromethyl)benzamide (10a) (102 mg, 0.2510 mmol) and chloromethyl chloroformate (77.67 mg, 52.30 μL, 0.6024 mmol) in CH2Cl2 (2 mL) was added DMF (200 μL) and the reaction mixture was stirred at room temperature for 1 hour. At this time, more chloromethyl chloroformate (77.67 mg, 52.30 μL, 0.6024 mmol) was added and the reaction mixture was heated to 70° C. for 25 min. The reaction mixture was diluted with EtOAc, the organic phase washed with sat. aq. NaHCO3, brine, dried with Na2SO4 and evaporated to dryness. The residue was taken up in DMF (3 mL), di-tert-butoxyphosphoryloxypotassium (249.3 mg, 1.004 mmol) and tetrabutylammonium iodide (9.271 mg, 0.02510 mmol) were added and the reaction mixture was stirred at 70° C. for 4 hours. The reaction mixture was cooled, diluted with water and extracted with EtOAc (3×). The organic layers were combined, washed with water then brine, dried with Na2SO4 and evaporated to dryness. Purification by column chromatography (12 g silica; 0-100% EtOAc in Hx) gave di-tert-butyl [4-[[2-(4-fluoro-2-methyl-phenoxy)-5-(trifluoromethyl)benzoyl]amino]-2-oxo-1-pyridyl]methyl phosphate (24) (23 mg, 0.03659 mmol, 14.6%) as a clear glass. ESI-MS m/z calc. 628.19617, found 629.5 (M+1)+; Retention time: 0.78 minutes

Provenance & Evidence