Trifluoroacetic acid → 6-methoxy-3,4-dihydro-2H-1,4-benzoxazin-3-one

Temperature

85 °C

2-bromo-N-[2-hydroxy-5-(methyloxy)phenyl]acetamide (3.42 g, 13.1 mmol), was dissolved in 120 mL of anhydrous dimethylformamide under argon. Potassium carbonate was added and suspended in the solution at room temperature. The mixture was warmed to 85° C. and refluxed for one hour before it was determined to be complete by LCMS (two Aquasil C 18, 20×1 mm columns were run in sequence, 4 minutes at 0.1 mL/min, 1-99% CH3CN/H2O with 0.018% trifluoroacetic acid, ES) Rt=1.1 min and m/e 180 [M+1]+. The mixture was allowed to cool to room temperature before it was diluted with 600 mL of ethyl acetate and washed with water (2×150 mL) and brine (2×150 mL). The organic phase was dried over Na2SO4, filtered and concentrated to give 6-(methyloxy)-2H-1,4-benzoxazin-3(4H)-one (2.08 g, 11.6 mmol, 88%) as a brown amorphous solid. MS (ES) m/e 180 [M+H]+.

1. customsuspended in the solution at room temperature
2. temperaturerefluxed for one hour before it
3. temperatureto cool to room temperature before it
4. washwashed with water (2×150 mL) and brine (2×150 mL)
5. dry with materialThe organic phase was dried over Na2SO4
6. filtrationfiltered
7. concentrationconcentrated

ORD record

ord-326866fd6d0f4f4595eb2902ee8914de

Source dataset

uspto-grants-2008_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07432258B2