Antiallergic activity of tetracyclic derivatives of quinoline-2-carboxylic acids. 1

Substitution of 1,4-dihydro-4-oxoquinoline-2-carboxylic acid by acetyl, benzoyl, and phenylsulfonyl substituents was found to enhance activity in the rat passive cutaneous anaphylaxis assay. A further increase in activity, to equipotency with DSCG, was achieved by incorporation of the 8-benzoyl moiety into a tetracyclic structure to give 1,4-dihydro-4,11(1H,11H)-dioxoindeno[1,2-h]quinoline-2-carboxylic acid (20). In contrast, the reverse isomer 19 was found to have little activity.