反应详情

5-Methylisatin (15.0 g) and 60 mL of hydrazine hydrate were heated to 140-160° C. for 4 hours. Thin layer chromatography (ethyl acetate:hexane 1:2, silica gel) showed no starting material remaining. The reaction mixture was cooled to room temperature, poured into 300 mL of ice water, and acidified to pH 2 with 6 N hydrochloric acid. After standing at room temperature for 2 days, the precipitate was collected by vacuum filtration, washed with water, and dried under vacuum to give 6.5 g (47%) of 5-methyl-2-oxindole.

1. filtrationthe precipitate was collected by vacuum filtration
2. washwashed with water
3. customdried under vacuum