1-Acetyl-6-aminoindoline → 1-(6-Hydroxyindolin-1-YL)ethanone

Participants

Reaction Steps

A solution of 1-acetyl-6-aminoindoline (D62, 12 g, 0.068 mol) in concentrated sulfuric acid (9 ml) and water (137 ml) was cooled to 0° C. and diazotised by the dropwise addition of sodium nitrite (4.8 g) in water (34 ml), maintaining the temperature at below 5° C. After 0.5 h, the reaction mixture was added to a boiling stirred solution of copper (II) sulfate (69 g) in water (120 ml). After evolution of nitrogen had ceased, the mixture was cooled, and the precipitate collected by filtration, washed with water, then dried. The compound was purified by column chromatography of its 0-acetyl derivative, then hydrolysed with aqueous NaOH at 20° C. over 18 hrs to afford the title compound as a grey solid (2.6 g, 22%).

Provenance & Evidence