反应详情

温度

70 °C

In 14 ml of N,N-dimethylformamide was suspended 0.38 g of sodium hydride (60% in oil) followed by addition of 1.00 g of 3,4-dihydro-2,2-dimethyl-7-nitro-2H-1,4-benzoxazine. Then, 1.01 g of 2-bromopyridine N-oxide hydrochloride was added with ice-cooling and the mixture was stirred at 70° C. for 16 hours. The reaction mixture was poured in ice-water and extracted with ethyl acetate. The organic layer was washed with aqueous sodium chloride solution and dried over anhydrous magnesium sulfate, and the solvent was distilled off. The residue was subjected to silica gel column chromatography and elution was carried out with chloroform-acetone (3:1) to give 0.34 g of 2-(3,4-dihydro-2,2-dimethyl-7-nitro-2H-1,4-benzoxazin-4-yl)pyridine N-oxide as oil. Then, a solution of hydrochloric acid in ethanol (prepared from 1 ml of concentrated hydrochloric acid and 5 ml of ethanol) was added thereto and the solvent was distilled off. The resulting residue wad recrystallized from acetone to give 182 mg of 2-(3,4-dihydro-2,2-dimethyl-7-nitro-2H-1,4-benzoxazin-4-yl)pyridine N-oxide hydrochloride.

1. temperaturecooling
2. extractionextracted with ethyl acetate
3. washThe organic layer was washed with aqueous sodium chloride solution
4. dry with materialdried over anhydrous magnesium sulfate
5. distillationthe solvent was distilled off
6. washThe residue was subjected to silica gel column chromatography and elution