Studies on antianaphylactic agents. 4. Synthesis and structure-activity relationships of 3-(4-oxo-4H-1-benzopyran-3)acrylic acids, a new series of antiallergic substances, and some related compounds.

The syntheses of trans-3-(4-oxo-4H-1-benzypyran-3)acrylic acid and a number of analogs shown to be highly active in antiallergic bioassays are described. These compounds are of possible value in the treatment of asthma. The structural requirements for biological activity are discussed with reference to the type of the substituents on the chromone ring or positions of linkage of the acrylic acid on the pyrone ring.