Cesium carbonate → 7-Methyl-6-(methyloxy)-2H-1,4-benzoxazin-3(4H)-one

Participants

Reaction Steps

To a solution of 2-amino-5-methyl-4-(methyloxy)phenol (3.0 g, 19 mmol) in CHCl3 (100 mL) were added saturated NaHCO3 (60 mL) and bromoacetyl bromide (5.78 g, 28.5 mmol) sequentially. The reaction mixture was vigorously stirred for 2 hours at room temperature, diluted with EtOAc (300 mL), washed with H2O, brine, and dried (Na2SO4). The solvent was removed via rotovap to give a brown solid. This brown solid was dissolved in DMF (200 mL), Cs2CO3 (6.19 g, 19 mmol) was added, and the reaction mixture was heated at 80° C. for 3 h. It was then poured into cold water (300 mL) and extracted with EtOAc (3×250 mL). The organic extracts were combined, washed with water, brine, and dried (MgSO4). The solvent was removed via rotovap, and the residue was purified on silica gel, using 50% EtOAc-Hexane, to give the title compound (2.13 g, 58%) as a brown solid. MS (ES) m/e 194 [M+H]+.

Provenance & Evidence