反应详情

2-(3-methoxyphenyl)acetyl chloride (1.18 mL; 7.57 mmol) was added to a mixture of ethyl 2-amino-2-(hydroxyimino)acetate (0.500 g; 3.78 mmol) and N,N diisopropylethylamine (1.05 mL; 6.06 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 formed precipitate was filtered off, suspended in pyridine (18 mL) and refluxed in a sealed tube for 20 h 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 0.146 g (15%) of ethyl 5-(3-methoxybenzyl)-1,2,4-oxadiazole-3-carboxylate as a yellow oil.

1. filtrationThe formed precipitate was filtered off
2. temperaturerefluxed in a sealed tube for 20 h
3. concentrationconcentrated under reduced pressure
4. customThe crude material was purified by flash chromatography on silica (eluent 20 to 100% ethyl acetate in heptane)