反应详情

To a solution of crude ethyl 5-oxo-4,5-dihydro-1,2,4-oxadiazole-3-carboxylate (2.4 g, 15.14 mmol) in MeOH (2 mL) is added aqueous 1M NaOH (4 mL, 4 mmol) at room temperature. After stirring for 5 hours at room temperature the reaction was quenched with 1N HCl (5 mL, 5 mmol), the crude is concentrated under reduced pressure to remove MeOH. The crude is diluted with EtOAc, the organic layer is washed with brine, dried over Na2SO4, filtered and concentrated under reduced pressure to give 5-oxo-4,5-dihydro-1,2,4-oxadiazole-3-carboxylic acid (1.9 g).

1. concentrationthe crude is concentrated under reduced pressure
2. customto remove MeOH
3. additionThe crude is diluted with EtOAc
4. washthe organic layer is washed with brine
5. dry with materialdried over Na2SO4
6. filtrationfiltered
7. concentrationconcentrated under reduced pressure