Biarylaniline phenethanolamines as potent and selective beta3 adrenergic receptor agonists.

The synthesis of a series of phenethanolamine aniline agonists that contain an aniline ring on the right-hand side of the molecule substituted at the meta position with a benzoic acid or a pyridyl carboxylate is described. Several of the analogues (e.g., 34, 36-38, 40, and 44) have high beta(3) adrenergic receptor (AR) potency and selectivity against beta(1) and beta(2) ARs in Chinese hamster ovary (CHO) cells expressing beta ARs. The dog pharmacokinetic profile of some of these analogues showed >25% oral bioavailability and po half-lives of at least 1.5 h. Among the compounds described herein, the 3,3'-biarylaniline carboxylate derivatives 36, 38 and the phenylpyridyl derivative 44 demonstrated outstanding in vitro properties and reasonable dog pharmacokinetic profiles. These three analogues also showed dose dependent beta(3) AR mediated responses in mice. The ease of synthesis and superior dog pharmacokinetics of compound 38 relative to that of 44 in combination with its in vitro profile led us to choose this compound as a development candidate for the treatment of type 2 diabetes.

Identification and structure-activity relationship of phenolic acyl hydrazones as selective agonists for the estrogen-related orphan nuclear receptors ERRbeta and ERRgamma.

The first small molecule agonists of the estrogen-related receptors have been identified. GSK4716 (3) and GSK9089 (4) show binding to ERRgamma with remarkable selectivity over the classical estrogen receptors. Notably, in cell-based reporter assays, 3 mimics the protein ligand PGC-1alpha in activation of human ERRbeta and ERRgamma.

A novel method for the generation of nitrile oxides on solid phase: application to the synthesis of substituted benzopyranoisoxazoles.

A solid-phase synthesis of substituted benzopyranoisoxazoles is described. The six-step synthesis features a novel method of generating nitrile oxides on a polymer support followed by an intramolecular 1,3-dipolar cycloaddition with a tethered alkyne for assembly of the benzopyranoisoxazole scaffold. Furthermore, the utilization of single-bead attenuated total reflectance Fourier transform infrared (ATR-IR) microspectroscopy as an essential analytical tool for reaction optimization is highlighted.

Structure-guided design of N-phenyl tertiary amines as transrepression-selective liver X receptor modulators with anti-inflammatory activity.

A cocrystal structure of T1317 (3) bound to hLXRbeta was utilized in the design of a series of substituted N-phenyl tertiary amines. Profiling in binding and functional assays led to the identification of LXR modulator GSK9772 ( 20) as a high-affinity LXRbeta ligand (IC 50 = 30 nM) that shows separation of anti-inflammatory and lipogenic activities in human macrophage and liver cell lines, respectively. A cocrystal structure of the structurally related analog 19 bound to LXRbeta reveals regions within the receptor that can affect receptor modulation through ligand modification. Mechanistic studies demonstrate that 20 is greater than 10-fold selective for LXR-mediated transrepression of proinflammatory gene expression versus transactivation of lipogenic signaling pathways, thus providing an opportunity for the identification of LXR modulators with improved therapeutic indexes.

Crystal structure of the PXR-T1317 complex provides a scaffold to examine the potential for receptor antagonism.

The human pregnane X receptor (PXR) recognizes a range of structurally and chemically distinct ligands and plays a key role in regulating the expression of protective gene products involved in the metabolism and excretion of potentially harmful compounds. The identification and development of PXR antagonists is desirable as a potential way to control the up-regulation of drug metabolism pathways during the therapeutic treatment of disease. We present the 2.8A resolution crystal structure of the PXR ligand binding domain (LBD) in complex with T0901317 (T1317), which is also an agonist of another member of the orphan class of the nuclear receptor superfamily, the liver X receptor (LXR). In spite of differences in the size and shape of the receptors' ligand binding pockets, key interactions with this ligand are conserved between human PXR and human LXR. Based on the PXR-T1317 structure, analogues of T1317 were generated with the goal of designing an PXR antagonist effective via the receptor's ligand binding pocket. We find that selectivity in activating PXR versus LXR was achieved; such compounds may be useful in addressing neurodegenerative diseases like Niemann-Pick C. We were not successful, however, in producing a PXR antagonist. Based on these observations, we conclude that the generation of PXR antagonists targeted to the ligand binding pocket may be difficult due to the promiscuity and structural conformability of this xenobiotic sensor.

Synthesis and evaluation of potent and selective beta3 adrenergic receptor agonists containing heterobiaryl carboxylic acids.

The design, synthesis, and SAR of a novel series of heterobiaryl phenethanolamine beta3 adrenergic receptor agonists are described. The furan analogue 49 was shown to elicit a significant dose-dependent lowering of plasma glucose in a rodent model of type 2 diabetes.

Structure-guided synthesis of tamoxifen analogs with improved selectivity for the orphan ERRgamma.

The design and synthesis of 4-hydroxytamoxifen (4-OHT) derivatives are described. The binding affinities of these compounds toward the orphan estrogen-related receptor gamma and the classical estrogen receptor alpha demonstrate that analogs bearing hydroxyalkyl groups display improved binding selectivity profiles compared with that of 4-OHT. An X-ray crystal structure of one of the designed compounds bound to ERRgamma LBD confirms the molecular basis of the selectivity.

Novel selective small molecule agonists for peroxisome proliferator-activated receptor delta (PPARdelta)--synthesis and biological activity.

We report the synthesis and biological activity of a new series of small molecule agonists of the human Peroxisome Proliferator-Activated Receptor delta (PPARdelta). Several hits were identified from our original libraries containing lipophilic carboxylic acids. Optimization of these hits by structure-guided design led to 7k (GW501516) and 7l (GW0742), which shows an EC(50) of 1.1 nM against PPARdelta with 1000-fold selectivity over the other human subtypes.