STUDIES ON ANTIASTHMATIC AGENTS——I.SYNTHESES OF SOME ANTIASTHMATIC 4-OXO-4H-1-BENZOPYRAN-3-CARBOXALDEHYDES AND TRANS-3-(4′-OXO-4′H-1′-BENZOPYRAN-3′)ACRYLIC ACIDS

A series of 4-oxo-4H-l-benzopyran-3-carboxaldehydes and trans-3-(4＇-oxo-4＇H-l＇-benzopyran-3＇) acrylic acids were synthsized and evaluated for antiasthmaticactivity.Three of these compounds(IX_a,IX_dandIX_i)showed significant antiasthmaticactivity in guinea pigs induced by histamine and acetylcholine.IX_a has been subjectedto clinical trials and proved to be effective in the treatment of certain types of asthmaand bronchitis.