Isatoic anhydride
Isatoic anhydride is an organic compound derived from anthranilic acid. A white solid, it is prepared by reaction of anthranilic acid with phosgene.Reactions
Hydrolysis gives carbon dioxide and anthranilic acid. Alcoholysis proceeds similarly, affording the ester:
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. Isatoic anhydride is used as a blowing agent in the polymer industry, an application that exploits its tendency to release CO2.
Isatoic anhydride has also been reported to be used as a precursor for the synthesis of methaqualone and related 4-quinazolinone based pharmaceutical drugs.
