[Structure-activity studies on carboxyflavone derivatives with antianaphylactic activity (author's transl)]

The passive cutaneous anaphylaxis (PCA) activities of a number of new A- and B-ring carboxyflavone and carboxyflavonol derivatives with planar and without planar orientation of the B-ring--synthesized in relation to baicalein and 2-carboxyxanthone derivatives as antianaphylactic prototypes--are recorded. From the investigated compounds A-ring carboxylic acids are more active than B-ring carboxy derivatives and flavonols are less active than flavones. Problems resulting from the correlation of the PCA activity of a number of chromone derivatives with the substitution of the 3-position are discussed.