Isatoic anhydride is an organic compound derived from anthranilic acid. A white solid, it is prepared by reaction of anthranilic acid with phosgene.[1]

Isatoic anhydride
Names
Preferred IUPAC name
2H-3,1-Benzoxazine-2,4(1H)-dione
Identifiers
ECHA InfoCard 100.003.869 Edit this at Wikidata
UNII
Properties
C8H5NO3
Molar mass 163.132 g·mol−1
Appearance white solid
Melting point 243 °C (469 °F; 516 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Reactions

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Hydrolysis gives carbon dioxide and anthranilic acid. Alcoholysis proceeds similarly, affording the ester:

C6H4C2O3NH + ROH → C6H4(CO2R)(NH2) + CO2

Amines also effect ring-opening. Active methylene compounds and carbanions replace oxygen giving hydroxyquinolinone derivatives. Deprotonation followed by alkylation gives the N-substituted derivatives. Sodium azide gives the benzimidazolone via the isocyanate.[2] Isatoic anhydride is used as a blowing agent in the polymer industry, an application that exploits its tendency to release CO2.

Uses

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Isatoic anhydride has been used as a precursor for the synthesis of methaqualone[3] and related 4-quinazolinone-based pharmaceutical drugs, including:

  1. Tioperidone
  2. Tranilast
  3. Pelanserin
  4. Diproqualone
  5. Antrafenine
  6. SJ-733
  7. Nicafenine
  8. Molinazone
  9. Cloperidone
  10. SGB 1534

References

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  1. ^ E. C. Wagner; Marion F. Fegley. (1947). "Isatoic anhydride". Org. Synth. 27: 45. doi:10.15227/orgsyn.027.0045.
  2. ^ Coppola, Gary M. (1980). "The Chemistry of Isatoic Anhydride". Synthesis. 7 (7): 505–36. doi:10.1055/s-1980-29110.
  3. ^ Etienne F. van Zyl (2001). "A survey of reported syntheses of methaqualone and some positional and structural isomers". Forensic Sci. Int. 122 (2–3): 142–149. doi:10.1016/S0379-0738(01)00484-4. PMID 11672968.