Nitric Acid → 5-Nitro-2-oxindole

Participants

Reaction Conditions

Reaction Steps

Fuming nitric acid (1.58 ml, 39.4 mmol) was added dropwise to a solution of oxindole (5 g, 37.5 mmol) in concentrated sulphuric acid (25 ml) cooled by an ice bath and maintained below 5° C. The mixture was stirred for 30 minutes at 0° C. and then poured into water. The precipitate was collected by filtration and thoroughly washed with water. The solid was suspended in 50% acetic acid (100 ml) and heated at 90° C. for 1 hour. The mixture was allowed to cool, the solid product was collected by filtration, washed with water and dried under vacuum over phosphorus pentoxide at 40° C. to give 5-nitrooxindole (3.2 g, 48%).

Provenance & Evidence