(p-Amylcinnamoyl)anthranilic acid (3a) had moderate antagonist activities against LTD4-induced smooth muscle contraction on guinea pig ileum and LTC4-induced bronchoconstriction in anesthetized guinea pigs. Modifications were made in the hydrophobic part (cinnamoyl moiety) and the hydrophilic part (anthranilate moiety) of 3a. A series of 8-(benzoylamino)-2-tetrazol-5-yl-1,4-benzodioxans and 8-(ben