2-cyano-1,3-dicarbonyl compounds with antiallergic activity.

A number of 2-cyanoindan-1,3-diones and 3-cyano-4-hydroxycoumarins have been prepared and assessed for potential antiallergy activity as measured by their ability to inhibit passive cutaneous anaphylaxis in the rat, mediated by rat serum containing antigen specific IgE. The structural requirements for activity were similar not only for both series of compounds but also for the analogous 2-nitroindan-1,3-diones and 4-hydroxy-3-nitrocoumarins previously reported. The most active compounds were 2-cyano-5,6-diethylindan-1,3-dione (4e) and 3-cyano-6,7-diethyl-4-hydroxycoumarin (11h).