Hydrochloric Acid → 5-Methylindolin-2-one

Reaction equation

[CH3:1][C:2]1[CH:3]=[C:4]2[C:8](=[CH:9][CH:10]=1)[NH:7][C:6](=[O:11])[C:5]2=O.O.NN.Cl>>[CH3:1][C:2]1[CH:3]=[C:4]2[C:8](=[CH:9][CH:10]=1)[NH:7][C:6](=[O:11])[CH2:5]2

Participants

Reactant 3

HCID 313Hydrochloric Acid

HCID 118405-Methylisatin

HCID 24654Hydrazine hydrate (1:1)

Product 1

HCID 53257165-Methylindolin-2-oneYield 47.5%

Conditions

Temperature: 150 °C

Procedure

A mixture of 5-methylisatin (15.0 g) and 60 ml of hydrazine hydrate was stirred at 140-160° C. for 4 hours. 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, a precipitate formed which was collected by vacuum filtration, washed with water and dried under vacuum to give 6.5 g (47% yield) of 5-methyl-2-oxindole.