反应详情

In 120 ml of dehydrated ethanol was suspended 11.05 g of 2-nitro-4-phenylsulfonylphenol followed by addition of a catalytic amount of Raney nickel for reduction in a hydrogen stream at atmospheric temperature and pressure. After completion of the reduction reaction, the catalyst was filtered off and the solvent was distilled off. The residue was dried under reduced pressure to give 9.73 g-of crude 2-amino-4-phenylsulfonylphenol. This product was dissolved in 19 ml of N,N-dimethylformamide and the solution was added dropwise to a mixture of 5.89 g of potassium fluoride, 7.61 g of ethyl 2-bromoisobutyrate and 11 ml of N,N-dimethylformamide. The mixture was then stirred at 60° C. overnight. The reaction mixture was poured in ice-water and extracted with ethyl acetate. The organic layer was washed with water and dried over anhydrous magnesium sulfate and the solvent was distilled off. The residue was chromatographed on a silica gel column and elution was carried out with hexane-ethyl acetate (2:1). The crude crystals from the eluate were recrystallized from 15 ml of ethanol to recover 4.706 g of 3,4-dihydro-2,2-dimethyl-3-oxo-6-phenylsulfonul-2H-1,4-benzoxazine.

1. customAfter completion of the reduction reaction
2. filtrationthe catalyst was filtered off
3. distillationthe solvent was distilled off
4. customThe residue was dried under reduced pressure