Oxindole

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.

Oxindole

Names
Preferred IUPAC name 1,3-Dihydro-2H-indol-2-one
Identifiers
CAS Number	59-48-3 Y
3D model (JSmol)	Interactive image
Beilstein Reference	114692
ChEBI	CHEBI:31697 Y
ChEMBL	ChEMBL40823 Y
ChemSpider	284794 Y
ECHA InfoCard	100.000.390
EC Number	200-429-5
Gmelin Reference	637057
KEGG	C12312 Y
MeSH	Oxindole
PubChem CID	321710
RTECS number	NM2080500
UNII	0S9338U62H Y
CompTox Dashboard (EPA)	DTXSID80870389
InChI InChI=1S/C8H7NO/c10-8-5-6-3-1-2-4-7(6)9-8/h1-4H,5H2,(H,9,10) Y Key: JYGFTBXVXVMTGB-UHFFFAOYSA-N Y
SMILES c1ccc2c(c1)CC(=O)N2
Properties
Chemical formula	C8H7NO
Molar mass	133.150 g·mol−1
Appearance	pale yellow solid
Melting point	128 °C (262 °F; 401 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

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 compounds^[2] including, for example, rhynchophylline, 3-methyloxindole,^[3] and semaxanib.^[4]

Rhynchophylline, a naturally occurring oxindole is a medicinal used as an NMDA antagonist and a calcium channel blocker.^[5]