Pirinixic acid derivatives as novel dual inhibitors of microsomal prostaglandin E2 synthase-1 and 5-lipoxygenase.

Dual inhibition of the prostaglandin (PG) and leukotriene (LT) biosynthetic pathway is supposed to be superior over single interference, both in terms of efficacy and side effects. Here, we present a novel class of dual microsomal PGE(2) synthase-1/5-lipoxygenase (5-LO) inhibitors based on the structure of pirinixic acid [PA, 2-(4-chloro-6-(2,3-dimethylphenylamino)pyrimidin-2-ylthio)acetic acid, compound 1]. Target-oriented structural modification of 1, particularly alpha substitution with extended n-alkyl or bulky aryl substituents and concomitant replacement of the 2,3-dimethylaniline by a biphenyl-4-yl-methane-amino residue, resulted in potent suppression of mPGES-1 and 5-LO activity, exemplified by 2-(4-(biphenyl-4-ylmethylamino)-6-chloropyrimidin-2-ylthio)octanoic acid (7b, IC(50) = 1.3 and 1 microM, respectively). Select compounds also potently reduced PGE(2) and 5-LO product formation in intact cells. Importantly, inhibition of cyclooxygenases-1/2 was significantly less pronounced. Taken together, these pirinixic acid derivatives constitute a novel class of dual mPGES-1/5-LO inhibitors with a promising pharmacological profile and a potential for therapeutic use.