Oxindole (2-indolone) is an aromatic heterocyclic organic compound with the formula C6H4CH2C(O)NH. It has a bicyclic structure, consisting of a six-membered benzene ring fused to a five-membered nitrogen-containing ring. Oxindole is a modified indoline with a substituted carbonyl at the second position of the 5-member indoline ring. Classified as a cyclic amide, it is a pale yellow solid.
Formation and reactions
Oxindole is derived in nature from tryptophan, formed by gut bacteria ("normal flora"). It is normally metabolized and detoxified from the body by the liver. In excess, it can cause sedation, muscle weakness, hypotension, and coma. Patients with hepatic encephalopathy have been recorded to have elevated serum oxindole levels.1
Treatment with phosphorus pentasulfide gives the thione.
Oxindoles
Beyond the parent compound, the oxindole structure is present in many compounds2 including, for example, rhynchophylline, 3-methyloxindole,3 and semaxanib.4
References
Riggio, Oliviero; Mannaioni, Guido; Ridola, Lorenzo; Angeloni, Stefania; Merli, Manuela; Carlà, Vincenzo; Salvatori, Filippo Maria; Moroni, Flavio (2 February 2010). "Peripheral and Splanchnic Indole and Oxindole Levels in Cirrhotic Patients: A Study on the Pathophysiology of Hepatic Encephalopathy". The American Journal of Gastroenterology. 105 (6): 1374–1381. doi:10.1038/ajg.2009.738. PMID 20125128. S2CID 20633097. /wiki/Doi_(identifier) ↩
Trost, Barry; Brennan, Megan (2009). "Asymmetric Syntheses of Oxindole and Indole Spirocyclic Alkaloid Natural Products". Synthesis. 2009 (18): 3003–3025. doi:10.1055/s-0029-1216975. /wiki/Doi_(identifier) ↩
Abraham S. Endler and Ernest I. Becker (1957). "3-Methyloxindole". Org. Synth. 37: 60. doi:10.15227/orgsyn.037.0060. /wiki/Doi_(identifier) ↩
Lubkoll, Jana; Millemaggi, Alessia; Perry, Alexis; Taylor, Richard J.K. (2010). "Tandem Horner–Wadsworth–Emmons/Heck procedures for the preparation of 3-alkenyl-oxindoles: The synthesis of Semaxanib and GW441756". Tetrahedron. 66 (33): 6606–6612. doi:10.1016/j.tet.2010.03.018. /wiki/Doi_(identifier) ↩