Chloromethyl chloroformate → Di-tert-butyl [4-[[4,5-dichloro-2-(4-fluoro-2-methoxy-phenoxy)benzoyl]amino]-2-oxo-1-pyridyl]methyl phosphate

Participants

Reaction Steps

To a solution of 4,5-dichloro-2-(4-fluoro-2-methoxy-phenoxy)-N-(2-oxo-1H-pyridin-4-yl)benzamide (1a) (101 mg, 0.2386 mmol) and chloromethyl chloroformate (36.92 mg, 24.86 μL, 0.2863 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, THF (1 mL) was added followed by more chloromethyl chloroformate (36.92 mg, 24.86 μL, 0.2863 mmol) and the reaction mixture stirred at room temperature for 1 h. More DMF (1 mL) and chloromethyl chloroformate (36.92 mg, 24.86 μL, 0.2863 mmol) was added and the reaction mixture was heated to 70° C. for 15 min. The reaction mixture was diluted with EtOAc and the organic phase washed with sat. aq. NaHCO3, brine, dried with Na2SO4 and evaporated to dryness. The residue was taken up in DMF (1.010 mL), di-tert-butoxyphosphoryloxypotassium (118.5 mg, 0.4772 mmol) and tetrabutylammonium iodide (8.813 mg, 0.02386 mmol) was added and the reaction mixture stirred at 70° C. for 4 h. 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-[[4,5-dichloro-2-(4-fluoro-2-methoxy-phenoxy)benzoyl]amino]-2-oxo-1-pyridyl]methyl phosphate (25) (40 mg, 0.06197 mmol, 26.0%) as a clear glass. ESI-MS m/z calc. 644.12573, found 647.3 (M+1)+; Retention time: 0.81 minutes

Provenance & Evidence