A series of 1, 4-dihydro-4-oxo-3-quinolinecarboxylic acids with a variety of substituents was prepared and evaluated in the rat passive cutaneous anaphylaxis test for antiallergic activity. The introduction of alkoxy group into 8 position of quinoline nucleus provided significantly active compounds. However, the conversion to 3-quinolinecarboxylic acids with alkoxy group at 6 or 7 position and the replacement of alkoxy group with alkylthio, alkylsulfonyl and other groups resulted in substantial reduction or loss of activity. Among the analogues, 8-butoxy-1, 4-dihydro-4-oxo-3-quinolinecarboxylic acid (69) was found to possess remarkably potent activity by oral administration. Structure-activity relationships are discussed.
