Trifluoroacetic acid → 7-(methyloxy)-6-(trifluoromethyl)-2H-1,4-benzoxazin-3(4H)-one

Ethyl {[5-(methyloxy)-2-nitro-4-(trifluoromethyl)phenyl]oxy}acetate (0.71 g, 2.2 mmol), was dissolved in 20 mL of ethanol. Tin chloride dihydrate (2.97 g, 12.5 mmol) was added to the solution and the mixture was stirred and maintained at room temperature for 18 hours. HPLC (Eclipse XDB-C18, 4.6×250 mm, 5 micron, 1-99% CH3CN/H2O with 0.1% trifluoroacetic acid) indicated that all of the starting material (Rt=7.65 min) was consumed and a new single peak formed (Rt=5.9 min). The mixture was allowed to cool to room temperature before all volatiles were removed by rotary evaporation. The crude residue was dissolved in 100 mL of ethyl acetate and washed with 10% hydrochloric acid solution (3×30 mL). The organic layer was dried over Na2SO4, filtered and concentrated. The crude material was purified by silica gel chromatography (40 g Redisep column, silica, 40 um, 60 Å, 35 mL/min, A: hexanes, B: ethyl acetate, B: 0% to 85% over 40 min; detection at 214 nm) to give 7-(methyloxy)-6-(trifluoromethyl)-2H-1,4-benzoxazin-3(4H)-one (0.39 g, 1.6 mmol, 73%) as an off-white amorphous solid. MS (ES) m/e 248 [M+H]+.

1. customwas consumed
2. customa new single peak formed (Rt=5.9 min)
3. temperatureto cool to room temperature before all volatiles
4. customwere removed by rotary evaporation
5. dissolutionThe crude residue was dissolved in 100 mL of ethyl acetate
6. washwashed with 10% hydrochloric acid solution (3×30 mL)
7. dry with materialThe organic layer was dried over Na2SO4
8. filtrationfiltered
9. concentrationconcentrated
10. customThe crude material was purified by silica gel chromatography (40 g Redisep column, silica, 40 um, 60 Å, 35 mL/min

ORD record

ord-20c0064cb86e4fb19046539a92c9fa65

Source dataset

uspto-grants-2008_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07432258B2