Fragmentation of GW4064 led to a highly potent partial farnesoid X receptor agonist with improved drug-like properties.

The ligand activated transcription factor farnesoid X receptor (FXR) is a crucial regulator of several metabolic and inflammatory pathways and its activation by agonistic ligands seems a valuable therapeutic approach for many disorders. Most known non-steroidal FXR agonists however, have limitations that hinder their clinical development and novel FXR ligands are required. Evaluation of the co-crystal structures of the widely used FXR agonist GW4064 and related compounds in complex with the FXR ligand binding domain indicated that their disubstituted isoxazole moiety is especially relevant for FXR activation. By investigation of GW4064-fragments missing the aromatic tail, we discovered a highly potent and soluble partial FXR agonist (14, ST-1892) as well as a fluorescent FXR ligand (15) as potential pharmacological tool.

Synthesis and biological evaluation of a class of 5-benzylidene-2-phenyl-thiazolinones as potent 5-lipoxygenase inhibitors.

A class of 5-lipoxygenase (5-LO) inhibitors characterized by a central 5-benzylidene-2-phenyl-thiazolinone scaffold was synthesized as a new series of molecular modifications and extensions of a previously reported series. Compounds were tested in a cell-based and a cell-free assay and furthermore evaluated for their influence on cell viability. The presented substituted thiazolinone scaffold turned out to be essential for both the 5-LO inhibitory activity and the non-cytotoxic profile. With (Z)-5-(4-methoxybenzylidene)-2-(naphthalen-2-yl)-5H-thiazol-4-one (2k, ST1237), a potent, direct, non-cytotoxic 5-LO inhibitor with IC(50) of 0.08 µM and 0.12 µM (cell-free assay and intact cells), we present a promising lead optimization and development for further investigations as novel anti-inflammatory drug.

Development and evaluation of ST-1829 based on 5-benzylidene-2-phenylthiazolones as promising agent for anti-leukotriene therapy.

Different inflammatory diseases and allergic reactions are mediated by leukotrienes, which arise from the oxygenation of arachidonic acid catalyzed by 5-lipoxygenase (5-LO). One promising approach for an effective anti-leukotriene therapy is the inhibition of this key enzyme. This study presents the synthesis and development of a potent and direct 5-LO inhibitor based on the well characterized 5-benzylidene-2-phenylthiazolone C06, whose further pharmacological investigation was precluded due to its low solubility. Through optimization of C06, evaluation of structure-activity relationships including profound assessment of the thiazolone core and consideration of the solubility, the 5-benzyl-2-phenyl-4-hydroxythiazoles represented by 46 (ST-1829, 5-(4-chlorobenzyl)-2-p-tolylthiazol-4-ol) were developed. Compound 46 showed an improved 5-LO inhibitory activity in cell-based (IC50 values 0.14 µM) and cell-free assays (IC50 values 0.03 µM) as well as a prominent enhanced solubility. Furthermore, it kept its promising inhibitory potency in the presence of blood serum, excluding excessive binding to serum proteins. These facts combined with the non-cytotoxic profile mark a major step towards an effective anti-inflammatory therapy.