反应详情

Benzoyl chloride (0.219 mL; 1.89 mmol) was added to a mixture of ethyl 2-amino-2-(hydroxyimino)acetate (0.250 g; 1.89 mmol) and N,N diisopropylethylamine (0.527 mL; 3.03 mmol) in dichloromethane (18 mL) at −15° C. The reaction mixture was stirred at room temperature overnight and poured into a mixture of ice and water. The aqueous layer was extracted with dichloromethane, and the combined organic extracts were dried and concentrated under reduced pressure. The residue was refluxed in a sealed tube with pyridine (6 mL) for 20 hours and concentrated under reduced pressure. The crude material was purified by flash chromatography on silica (eluent 20 to 100% ethyl acetate in heptane) to yield 0.239 (60%) of ethyl 5-phenyl-1,2,4-oxadiazole-3-carboxylate as a yellow solid.

1. extractionThe aqueous layer was extracted with dichloromethane
2. customthe combined organic extracts were dried
3. concentrationconcentrated under reduced pressure
4. temperatureThe residue was refluxed in a sealed tube with pyridine (6 mL) for 20 hours
5. concentrationconcentrated under reduced pressure
6. customThe crude material was purified by flash chromatography on silica (eluent 20 to 100% ethyl acetate in heptane)