Synthesis and pharmacological evaluation of new cysLT1 receptor antagonists

Summary This paper describes the synthesis and pharmacological evaluation of three series of compounds 4a–b , 13a–k and 19 , structurally related to the known potent cysLT 1 receptor antagonists RG-12553, ICI-204219 and ONO-1078 , respectively. The common structural feature of these new series is the presence of a 4-quinolone nucleus acting as a template for substitution of the aromatic nucleus present in the prototype antagonists. We describe the evolution of these series leading to antagonists with potency at nanomolar concentrations in vitro.