反应详情

5-Methyl-6-nitro-1H-benzo[d][1,3]oxazine-2,4-dione (8 g, 36.0 mmol) prepared from 2-Amino-6-methyl-benzoic acid (Aldrich) as described by Abood, N. A., et al. (1997) Bioorganic & Med. Chem. Lett. 7: 2105-2108 and sodium carbonate (3.82, 36.0 mmol) were stirred in methanol (180 mL, 0.1 M) at 0° C. for 0.5 hours and then at ambient temperature for 3 hours. Strongly acidic ion-exchange resin (Dowex® 50 WX4-200) was added until neutral pH and the solution was filtered. The solvent was removed under reduced pressure and silica gel chromatography (60:40 hexane/ethyl acetate) afforded Intermediate 1(a) (6.59 g) in 87% yield.

1. additionStrongly acidic ion-exchange resin (Dowex® 50 WX4-200) was added until neutral pH
2. filtrationthe solution was filtered
3. customThe solvent was removed under reduced pressure and silica gel chromatography (60:40 hexane/ethyl acetate)