We present a novel class of dual modulators of gamma-secretase and peroxisome proliferator-activated receptor gamma (PPARgamma) based on the structure of 2-(bis(phenethoxy)pyrimidine-2-ylthio)hexanoic acid 8 (IC(50)(Abeta42) = 22.8 microM, EC(50)(PPARgamma) = 8.3 microM). The modulation of both targets with approved drugs (i.e., amyloid-beta 42 (Abeta42)-lowering NSAIDs for gamma-secretase and glitazones for PPARgamma) has demonstrated beneficial effects in in vitro and in vivo models of Alzheimer's disease (AD). However, although NSAIDs and PPARgamma agonists share similar structural features, no druglike compounds with dual activities as gamma-secretase modulators (GSMs) and PPARgamma agonists have been designed so far. On the basis of our initial lead structure 8, we present the structure-activity relationships (SARs) of broad structural variations. A significant improvement was reached by the introduction of p-trifluoromethyl substituents at the phenyl residues yielding compound 16 (IC(50)(Abeta42) = 6.0 microM, EC(50)(PPARgamma) = 11.0 microM) and the replacement of the two phenyl residues of 8 by cyclohexyl yielding compound 22 (IC(50)(Abeta42) = 5.1 microM, EC(50)(PPARgamma) = 6.6 microM).

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Various inflammatory diseases are associated with the excessive formation of leukotrienes (LTs) and prostaglandins (PGs). Herein, we present a novel class of dual inhibitors of 5-lipoxygenase (5-LO) and microsomal prostaglandin E(2) synthase-1 (mPGES-1), key enzymes in the formation of LTs and PGE(2), respectively. On the basis of the structure of 2-[(4,6-diphenethoxypyrimidin-2-yl)thio]hexanoic acid (1), we performed a detailed SAR analysis, and mechanistic studies were carried out to elucidate the mode of 5-LO inhibition. Interestingly, the pyrimidine ring including the thioether of 1 could be replaced by a simple benzyl or a benzylidene moiety yielding a novel series of bioactive 2-benzylidene- and 2-benzylhexanoic acids exemplified by 2-(2,3-diphenethoxybenzylidene)hexanoic acid, 29 (IC(50) 5-LO = 0.8 μM; mPGES-1 = 1.1 μM). Importantly, none of the novel bioactive derivatives strongly inhibited cyclooxygenase activities. Together, we provide novel promising lead compounds for the treatment of inflammatory diseases valuable for further investigations in vivo.

Pirinixic acid is a moderate agonist of both the alpha and the gamma subtype of the peroxisome proliferator activated receptor (PPAR). Previously, we have shown that a-alkyl substitution leads to balanced low micromolar-active dual agonists of PPARa and PPARg. Taking a-hexyl pirinixic acid as a new scaffold, we further optimized PPAR activity by enlargement of the lipophilic backbone by substituting the 2,3-dimethylphenyl with biphenylic moieties. Such a substitution pattern had only minor impact on PPARg activity but further increased PPARa activity leading to nanomolar activities. Supporting docking studies proposed that the (R)-enantiomer should fit the PPARa ligand-binding pocket better and thus be more active than the (S)-enantiomer. Single enantiomers of selected active analogues were then prepared by enantio-selective synthesis and enantioselective preparative HPLC, respectively. Biological data for the distinct enantiomers fully corroborated the docking experiments and substantiate a stereochemical impact on PPAR activation.

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