From Wikipedia, the free encyclopedia
Jump to: navigation, search
CAS number 91-56-5 YesY
ChemSpider 6787 YesY
DrugBank DB02095
KEGG C11129 YesY
ChEBI CHEBI:27539 YesY
Jmol-3D images Image 1
Molecular formula C8H5NO2
Molar mass 147.1308 g/mol
Appearance Orange-red solid
Melting point 200 °C (392 °F; 473 K)
EU classification Harmful (Xn)
R-phrases R22 R36 R37 R38
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY (verify) (what is: YesY/N?)
Infobox references

Isatin or 1H-indole-2,3-dione is an indole derivative. The compound was first obtained by Erdmann[1] and Laurent[2] in 1841 as a product from the oxidation of indigo dye by nitric acid and chromic acids. The compound is found in many plants, such as Isatis tinctoria, Calanthe discolor and in Couroupita guianensis.[3]

Schiff bases of isatin are investigated for their pharmaceutical properties.[4]

Isatin forms a blue dye (indophenin) if it is mixed with sulfuric acid and crude benzene. The formation of the indophenin was long believed to be a reaction with benzene. Victor Meyer was able to isolate the substance responsible for this reaction from crude benzene. This new heterocyclic compound was thiophene.[5]


Isatin is commercially available. It may be prepared from cyclicizing the condensation product of chloral hydrate, aniline and hydroxylamine in sulfuric acid. This reaction is called the Sandmeyer isonitrosoacetanilide Isatin Synthesis and was discovered by Traugott Sandmeyer in 1919:[6][7]

Synthesis of isatin.png

Another classic reaction, the Sandmeyer diphenylurea isatin synthesis (Sandmeyer 1903), starts from diphenylthiourea, potassium cyanide, and lead carbonate.[8]

Isatins can be made from the corresponding indole in good yield by a mix of InCl3 and IBX in an acetonitrile-water solution at 80°C.[9]


Isatin is used as an intermediate in the syntheses of diclofenac, pirquinozol,[10] and talnetant.

See also[edit]


  1. ^ Erdmann, O. L. (1840). "Untersuchungen über den Indigo". Journal für Praktische Chemie 19 (1): 321–362. doi:10.1002/prac.18400190161. 
  2. ^ Laurent, A. (1840). "Recherches sur l'indigo". Annales de Chimie et de Physique 3 (3): 393–434. 
  3. ^ da Silva, J. F. M.; Garden, S. J.; Pinto, A. C. (2001). "The Chemistry of Isatins: a Review from 1975 to 1999" (pdf). Journal of the Brazilian Chemical Society 12 (3): 273–324. doi:10.1590/S0103-50532001000300002. 
  4. ^ Jarrahpour, A. A.; Khalili, D. (2005). "Synthesis of 3,3´-[methylenebis(3,1-phenylenenitrilo)]bis[1,3-dihydro]-2H-indol-2-one as a Novel bis-Schiff Base" (pdf). Molbank 2005 (4): M437. doi:10.3390/M437. 
  5. ^ Sumpter, W. C. (1944). "The Chemistry of Isatin". Chemical Reviews 34 (3): 393–434. doi:10.1021/cr60109a003. 
  6. ^ Marvel, C. S.; Hiers, G. S. (1925), "Isatin", Org. Synth. 5: 71 ; Coll. Vol. 1: 327 
  7. ^ Sandmeyer, T. (1919). "Über Isonitrosoacetanilide und deren Kondensation zu Isatinen". Helvetica Chimica Acta 2 (1): 234–242. doi:10.1002/hlca.19190020125. 
  8. ^ "Isatin Synthesis". 
  9. ^ Yadav, J. S.; Reddy, B. V. S.; Reddy, Ch. S.; Krishna, A. (2007). "Indium(III) Chloride / 2-Iodoxybenzoic Acid: A Novel Reagent System for the Conversion of Indoles to Isatins". Synthesis 2007 (5): 693–696. doi:10.1055/s-2007-965930. 
  10. ^ Vogt, B. R.; U.S. Patent 4,076,818 (1978)

Further reading[edit]