New diphenolic azoles as highly selective estrogen receptor-beta agonists are reported. The more potent and selective analogues of these series have comparable binding affinities for ERbeta as the natural ligand 17beta-estradiol but are >100-fold selective over ERalpha. Our design strategy not only followed a traditional SAR approach but also was supported by X-ray structures of ERbeta cocrystallized with various ligands as well as molecular modeling studies. These strategies enabled us to take advantage of a single conservative residue substitution in the ligand-binding pocket, ERalpha Met(421) --> ERbeta Ile(373), to optimize ERbeta selectivity. The 7-position-substituted benzoxazoles (Table 5) were the most selective ligands of both azole series, with ERB-041 (117) being >200-fold selective for ERbeta. The majority of ERbeta selective agonists tested that were at least approximately 50-fold selective displayed a consistent in vivo profile: they were inactive in several models of classic estrogen action (uterotrophic, osteopenia, and vasomotor instability models) and yet were active in the HLA-B27 transgenic rat model of inflammatory bowel disease. These data suggest that ERbeta-selective agonists are devoid of classic estrogenic effects and may offer a novel therapy to treat certain inflammatory conditions.

The identification of small molecule aminohydantoins as potent and selective human beta-secretase inhibitors is reported. These analogues exhibit low nannomolar potency for BACE1, show comparable activity in a cell-based (ELISA) assay, and demonstrate >100x selectivity for the other structurally related aspartyl proteases BACE2, cathepsinD, renin, and pepsin. On the basis of the cocrystal structure of the HTS-hit 2 in the BACE1 active site and by use of a structure-based drug design approach, we methodically explored the comparatively large binding pocket of the BACE1 enzyme and identified key interactions between the ligand and the protein that contributed to the affinity. One of the more potent compounds, (S)-55, displayed an IC(50) value for BACE1 of 10 nM and exhibited comparable cellular activity (EC(50) = 20 nM) in the ELISA assay. Acute oral administration of (S)-55 at 100 mg/kg resulted in a 69% reduction of plasma A beta(40) at 8 h in a Tg2576 mouse (p < 0.001).

The identification of small molecule aminoimidazoles as potent and selective human beta-secretase inhibitors is reported. These analogues demonstrate low nannomolar potency for BACE1 in a FRET assay, exhibit comparable activity in a cell-based (ELISA) assay, and show >100x selectivity for the other structurally related aspartyl proteases BACE2, cathepsin D, renin, and pepsin. Our design strategy was supported by molecular modeling studies based on the cocrystal structure of the HTS-hit 3 in the BACE1 active site. These strategies enabled us to integrate pyridine and pyrimidine groups on 3 extending deep into the S3 region of the BACE1 binding pocket and enhancing the ligand's potency. Compound (R)-37 displayed an IC50 value for BACE1 of 20 nM, cellular activity of 90 nM, and >100-fold selectivity over related aspartyl proteases. Acute oral administration of (R)-37 at 30 mg/kg resulted in a significant 71% reduction of plasma Abeta40 measured at the 6 h time point in a Tg2576 mouse model (p < 0.001).

Insulin resistance in the liver and peripheral tissues together with a pancreatic cell defect are the common causes of type 2 diabetes. It is now appreciated that insulin resistance can result from a defect in the insulin receptor signaling system, at a site post binding of insulin to its receptor. Protein tyrosine phosphatases (PTPases) have been shown to be negative regulators of the insulin receptor. Inhibiton of PTPases may be an effective method in the treatment of type 2 diabetes. A series of azolidinediones has been prepared as protein tyrosine phosphatase 1B (PTP1B) inhibitors. Several compounds were potent inhibitors against the recombinant rat and human PTP1B enzymes with submicromolar IC(50) values. Elongated spacers between the azolidinedione moiety and the central aromatic portion of the molecule as well as hydrophobic groups at the vicinity of this aromatic region were very important to the inhibitory activity. Oxadiazolidinediones 87 and 88 and the corresponding acetic acid analogues 119 and 120 were the best h-PTP1B inhibitors with IC(50) values in the range of 0.12-0.3 microM. Several compounds normalized plasma glucose and insulin levels in the ob/ob and db/db diabetic mouse models.

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