A systematic structure-activity exploration of the carboxylic acid region in a series of indole- or indazole-derived leukotriene antagonists 1 led to several discoveries. Use of the 3-methoxy-p-tolyl fragment (illustrated in acid 1) for connecting the indole and the acidic site provides the most potent carboxylic acids 1, tetrazoles 20, and aryl sulfonimides 21. The aryl sulfonimides are 5-500 times more potent (in vitro and/or in vivo) than the corresponding carboxylic acids 1. The o-tolyl sulfonimides such as 114 show greater oral potency than the phenyl sulfonimides at a given level of in vitro activity. Acidic keto sulfone derivatives 10 (Nu = CH-(CO2CH3)SO2Ph) mimic the activity of the sulfonimides.
The synthesis and biological characterization of a series of novel leukotriene antagonists and agonists are reported. All of these compounds are derivatives of (5S,6R,7Z)-5-hydroxy-6-mercapto-9-phenyl-7-nonenoic acid. One of the more potent compounds is (5S,6R,7Z)-6-[[(4-carboxy-2-methoxyphenyl)methyl]thio]-5-hydroxy-9 -(4- heptylphenyl)-7-nonenoic acid (3f). In vitro evaluation of this compound on guinea pig trachea revealed that it is a competitive antagonist of LTD4 and LTE4 with pKB values of 6.4 and 5.8, respectively. On guinea pig ileum, the pKB values obtained for it with LTD4 and E4 were both 7.2. The selectivity of 3f was shown by its lack of effect on carbachol, histamine, and barium chloride concentration-response curves in guinea pig trachea.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.