isatin

Isatin is a small molecule and an indole derivative with the chemical formula C8H5NO2. It was first discovered in 1841 as an oxidation product of indigo dye. Structurally, it consists of a fused benzene ring and a five-membered nitrogen-containing ring (indole core) with carbonyl groups at positions 2 and 3. Isatin acts as both an electrophile and nucleophile in organic synthesis due to its unique reactivity profile[1][3][6]. It has been widely used as a building block for pharmaceuticals, dyes, and other organic compounds. Biologically, isatin exhibits monoamine oxidase (MAO) inhibitory activity—particularly against MAO-B—which can increase dopamine levels in the brain[1][6]. Derivatives of isatin have been investigated for potential anticonvulsant, antitumor, antibacterial, antifungal, antitubercular, antiviral activities among others[6]. However, isatin itself has not been approved for clinical use as a pharmaceutical drug but remains important in medicinal chemistry research.

Other names

1H-indole-2,3-dione2,3-indolinedionetribulin2,3-dioxoindolineindenedioneindole quinone