反应详情

To a mixture of N′-hydroxy-2-(4-nitrophenyl)ethanimidamide (2.38 g) and N,N-dimethylacetamide (30 mL) was added acetyl chloride (0.96 g) at room temperature and the mixture was stirred at room temperature for 15 hrs. Water was poured into the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated brine, dried over anhydrous magnesium sulfate and concentrated. A mixture of obtained residue and xylene (100 mL) was heated under reflux for 24 hrs. The reaction mixture was concentrated and ethyl acetate was added to the obtained residue. The mixture was washed with saturated brine, dried over anhydrous magnesium sulfate, and concentrated. The residue was subjected to silica gel column chromatography to give 5-methyl-3-(4-nitrobenzyl)-1,2,4-oxadiazole as orange crystals (1.00 g, yield 37%) from a fraction eluted with hexane-ethyl acetate (4:1-3:1, v/v). Recrystallization thereof from ethyl acetate-hexane gave orange prism crystals. melting point: 66-67° C.

1. extractionthe mixture was extracted with ethyl acetate
2. washThe organic layer was washed with saturated brine
3. dry with materialdried over anhydrous magnesium sulfate
4. concentrationconcentrated
5. additionA mixture of obtained residue and xylene (100 mL)
6. temperaturewas heated
7. temperatureunder reflux for 24 hrs
8. concentrationThe reaction mixture was concentrated
9. additionethyl acetate was added to the obtained residue
10. washThe mixture was washed with saturated brine
11. dry with materialdried over anhydrous magnesium sulfate
12. concentrationconcentrated