Synthesis of butanoic acid 4,4′-[(4E, 6Z, 9Z-pentadecatrien-2-ynylidene)-bis with leukotriene- like activity: Novel acetylenic acetals and dithioacetals as antagonists of leukotriene-C4

Abstract A selective exchange reaction of the symmetrical acetal 5a with protected cysteine readily provided the hemi-thioacetals 9a and 11a related to leukotriene-E 4 . Use of acetylene-bis-(diethyl acetal) 12 led to a facile synthesis of the title compound 17a. Its corresponding hexahydro analogs displayed marked antagonist activity against LT-C 4 induced contractions on isolated guinea pig lung parenchyma.