Design and synthesis of functionalized piperazin-1yl-(E)-stilbenes as inhibitors of 17α-hydroxylase-C17,20-lyase (Cyp17).

The synthesis of steroid hormones is critical to human physiology and improper regulation of either the synthesis of these key molecules or activation of the associated receptors can lead to disease states. This has led to intense interest in developing compounds capable of modulating the synthesis of steroid hormones. Compounds capable of inhibiting Cyp19 (Aromatase), a key enzyme in the synthesis of estrogens, have been successfully employed as breast cancer therapies, while inhibitors of Cyp17 (17α-hydroxylase-17,20-lyase), a key enzyme in the synthesis of glucocorticoids, mineralocorticoids and steroidal sex hormones, are a key component of prostate cancer therapy. Inhibition of CYP17 has also been suggested as a possible target for the treatment of Cushing Syndrome and Metabolic Syndrome. We have identified two novel series of stilbene based CYP17 inhibitors and demonstrated that exemplary compounds in these series have pharmacokinetic properties consistent with orally delivered drugs. These findings suggest that compounds in these classes may be useful for the treatment of diseases and conditions associated with improper regulation of glucocorticoids synthesis and glucocorticoids receptor activation.

Design, synthesis, and evaluation of (2S,4R)-Ketoconazole sulfonamide analogs as potential treatments for Metabolic Syndrome.

Metabolic Syndrome, also referred to as 'Syndrome X' or 'Insulin Resistance Syndrome,' remains a major, unmet medical need despite over 30years of intense effort. Recent research suggests that there may be a causal link between this condition and abnormal glucocorticoid processing. Specifically, dysregulation of the hypothalamic-pituitary-adrenocortical (HPA) axis leads to increased systemic cortisol concentrations. Cushing' syndrome, a disorder that is also typified by a marked elevation in levels of cortisol, produces clinical symptomology that is similar to those observed in MetS, and they can be alleviated by decreasing circulating cortisol concentrations. As a result, it has been suggested that decreasing systemic cortisol concentration might have a positive impact on the progression of MetS. This could be accomplished through inhibition of enzymes in the cortisol synthetic pathway, 11ß-hydroxylase (Cyp11B1), 17α-hydroxylase-C17,20-lyase (Cyp17), and 21-hydroxylase (Cyp21). We have identified a series of novel sulfonamide analogs of (2S,4R)-Ketoconazole that are potent inhibitors of these enzymes. In addition, selected members of this class of compounds have pharmacokinetic properties consistent with orally delivered drugs, making them well suited to further investigation as potential therapies for MetS.

Novel benzofuran derivatives with dual 5-HT1A receptor and serotonin transporter affinity.

Several benzofuran derivatives linked to a 3-indoletetrahydropyridine through an alkyl chain were prepared and evaluated for serotonin transporter and 5-HT(1A) receptor affinities. Their design, synthesis and structure-activity relationships are described.

Identification of a new class of small molecule C5a receptor antagonists.

C5a is a terminal product of the complement cascade that activates and attracts inflammatory cells including granulocytes, mast cells and macrophages via a specific GPCR, the C5a receptor (C5aR). Inhibition of C5a/C5aR interaction has been shown to be efficacious in several animal models of autoimmune diseases, including RA, SLE and asthma. This account reports the discovery of a new class of C5aR antagonists through high-throughput screening. The lead compounds in this series are selective and block C5a binding, C5a-promoted calcium flux in human neutrophils with nanomolar potency.

Benzimidazole- and indole-substituted 1,3'-bipyrrolidine benzamides as histamine H3 receptor antagonists.

Using a focused screen of biogenic amine compounds we identified a novel series of H(3)R antagonists. A preliminary SAR study led to reduction of MW while increasing binding affinity and potency. Optimization of the physical properties of the series led to (S)-6n, with improved brain to plasma exposure and efficacy in both water intake and novel object recognition models.

Novel imidazolopyrimidines as dual PI3-Kinase/mTOR inhibitors.

This article describes the syntheses and SAR of a series of imidazolopyrimidine derivatives, which are evaluated as inhibitors of PI3-Kinase (PI3K) and mTOR. These compounds were found to be ATP competitive with good tumor cell growth inhibition, and suppression of pathway specific biomakers such as phosphorylation of Akt at T308.

Discovery and initial optimization of 5,5'-disubstituted aminohydantoins as potent beta-secretase (BACE1) inhibitors.

8,8-Diphenyl-2,3,4,8-tetrahydroimidazo[1,5-a]pyrimidin-6-amine (1) was identified through HTS, as a weak (micromolar) inhibitor of BACE1. X-Ray crystallographic studies indicate the 2-aminoimidazole ring forms key H-bonding interactions with Asp32 and Asp228 in the catalytic site of BACE1. Lead optimization using structure-based focused libraries led to the identification of low nanomolar BACE1 inhibitors such as 20b with substituents which extend from the S(1) to the S(3) pocket.

(S)-N-(5-Chlorothiophene-2-sulfonyl)-beta,beta-diethylalaninol a Notch-1-sparing gamma-secretase inhibitor.

Accumulation of beta-amyloid (Abeta), produced by the proteolytic cleavage of amyloid precursor protein (APP) by beta- and gamma-secretase, is widely believed to be associated with Alzheimer's disease (AD). Research around the high-throughput screening hit (S)-4-chlorophenylsulfonyl isoleucinol led to the identification of the Notch-1-sparing (9.5-fold) gamma-secretase inhibitor (S)-N-(5-chlorothiophene-2-sulfonyl)-beta,beta-diethylalaninol 7.b.2 (Abeta(40/42) EC(50)=28 nM), which is efficacious in reduction of Abeta production in vivo.

Synthesis and activity of tryptophan sulfonamide derivatives as novel non-hydroxamate TNF-alpha converting enzyme (TACE) inhibitors.

A novel series of non-hydroxamate tryptophan sulfonamide derivatives containing a butynyloxy P1' moiety was identified as inhibitors of TNF-alpha converting enzyme (TACE). The structure-activity relationship of the series was examined via substitution on the tryptophan indole ring. Of the compounds investigated, 2-(4-(but-2-ynyloxy)phenylsulfonamido)-3-(1-(4-methoxybenzyl)-1H-indol-3-yl)propanoic acid (12p) has the best in vitro potency against isolated TACE enzyme with an IC(50) of 80 nM. Compound 12p also shows good selectivity over MMP-1, -13, -14.

Discovery of benzisoxazoles as potent inhibitors of chaperone heat shock protein 90.

Heat shock protein 90 (Hsp90) is a molecular chaperone that is responsible for activating many signaling proteins and is a promising target in tumor biology. We have identified small-molecule benzisoxazole derivatives as Hsp90 inhibitors. Crystallographic studies show that these compounds bind in the ATP binding pocket interacting with the Asp93. Structure based optimization led to the identification of potent analogues, such as 13, with good biochemical profiles.

Acylguanidine inhibitors of beta-secretase: optimization of the pyrrole ring substituents extending into the S1' substrate binding pocket.

The proteolytic enzyme beta-secretase (BACE-1) produces amyloid beta (Abeta) peptide, the primary constituent of neurofibrillary plaques, implicated in Alzheimer's disease, by cleavage of the amyloid precursor protein. A small molecule inhibitor of BACE-1, (diaminomethylene)-2,5-diphenyl-1H-pyrrole-1-acetamide (1, BACE-1 IC(50)=3.7 microM), was recently described, representing a new small molecule lead. Initial SAR investigation demonstrated the potential of accessing the nearby S(3) and S(1)(') substrate binding pockets of the BACE-1 enzyme by building substituents off one of the phenyl substituents and guanidinyl functional group. We report here the optimization of guanidinyl functional group substituents on 1, leading to potent submicromolar BACE-1 inhibitors.

Discovery of a novel series of Notch-sparing gamma-secretase inhibitors.

Using a cell-based assay, we have identified a new series of Notch-sparing gamma-secretase inhibitors from HTS screening leads 2a and 2e. Lead optimization studies led to the discovery of analog 8e with improved gamma-secretase inhibitory potency and Notch-sparing selectivity.

Acylguanidine inhibitors of beta-secretase: optimization of the pyrrole ring substituents extending into the S1 and S3 substrate binding pockets.

Proteolytic cleavage of amyloid precursor protein by beta-secretase (BACE-1) and gamma-secretase leads to formation of beta-amyloid (A beta) a key component of amyloid plaques, which are considered the hallmark of Alzheimer's disease. Small molecule inhibitors of BACE-1 may reduce levels of A beta and thus have therapeutic potential for treating Alzheimer's disease. We recently reported the identification of a novel small molecule BACE-1 inhibitor N-[2-(2,5-diphenyl-pyrrol-1-yl)-acetyl]guanidine (3.a.1). We report here the initial hit-to-lead optimization of this hit and the SAR around the aryl groups occupying the S(1) and S(2') pockets leading to submicromolar BACE-1 inhibitors.

Discovery of N1-(6-chloroimidazo[2,1-b][1,3]thiazole-5-sulfonyl)tryptamine as a potent, selective, and orally active 5-HT(6) receptor agonist.

N1-Arylsulfonyltryptamines have been identified as 5-HT6 receptor ligands. In particular, N1-(6-chloroimidazo[2,1-b][1,3]thiazole-5-sulfonyl)tryptamine (11q) is a high affinity, potent full agonist (5-HT6 Ki = 2 nM, EC50 = 6.5 nM, Emax = 95.5%). Compound 11q is selective in a panel of over 40 receptors and ion channels, has good pharmacokinetic profile, has been shown to increase GABA levels in the rat frontal cortex, and is active in the schedule-induced polydipsia model for obsessive compulsive disorders.

Discovery of proline sulfonamides as potent and selective hepatitis C virus NS5b polymerase inhibitors. Evidence for a new NS5b polymerase binding site.

Through high throughput screening, substituted proline sulfonamide 6 was identified as HCV NS5b RNA-dependent RNA polymerase inhibitor. Optimization of various regions of the lead molecule resulted in compounds that displayed good potency and selectivity. The crystal structure of 6 and NS5b polymerase complex confirmed the binding near the active site region. The optimization approach and SAR are discussed in detail.

Acylguanidines as small-molecule beta-secretase inhibitors.

BACE1 is an aspartyl protease responsible for cleaving amyloid precursor protein to liberate Abeta, which aggregates leading to plaque deposits implicated in Alzheimer's disease. We have identified small-molecule acylguanidine inhibitors of BACE1. Crystallographic studies show that these compounds form unique hydrogen-bonding interactions with the catalytic site aspartic acids and stabilize the protein in a flap-open conformation. Structure-based optimization led to the identification of potent analogs, such as 10d (BACE1 IC(50) = 110 nM).

Discovery of 5-arylsulfonamido-3-(pyrrolidin-2-ylmethyl)-1H-indole derivatives as potent, selective 5-HT6 receptor agonists and antagonists.

5-Arylsulfonylamido-3-(pyrrolidin-2-ylmethyl)-1H-indoles have been identified as high-affinity 5-HT(6) receptor ligands. Within this class, several of the (R)-enantiomers were potent agonists having EC(50) values of 1 nM or less and functioning as full agonists while the (S)-enantiomers displayed moderate antagonist activity.

Pyrazolopyrimidine-2,4-dione sulfonamides: novel and selective calcitonin inducers.

A series of pyrazolo[4,3-d]pyrimidine sulfonamides and pyrazolo[3,4-d]pyrimidine sulfonamides have been synthesized. These compounds increase transcription of a calcitonin-luciferase promoter and production of cellular calcitonin in a calcitonin-secretion/RIA assay with minimized phosphodiesterase type 4 inhibitory activity at 30 microM as compared to structurally related xanthine methylene ketones such as denbufyllene. These two series are notable examples of small molecules that act as CT-inducers, a method to potentially treat bone loss diseases.

Design and syntheses of 1,6-naphthalene derivatives as selective HCMV protease inhibitors.

Through high throughput screening of various libraries, substituted styryl naphthalene 6 was identified as an HCMV protease inhibitor. Optimization of various regions of the lead molecule using parallel synthesis resulted in 1,6-substituted naphthalenes 19d-i. These compounds displayed good potency and were selective over elastase, trypsin, and chymotrypsin. The optimization approach on lead compound 6 in three different regions of the molecule using parallel solution-phase synthesis and the corresponding SAR are discussed in detail.

Discovery of pyrano[3,4-b]indoles as potent and selective HCV NS5B polymerase inhibitors.

A novel series of HCV NS5B RNA-dependent RNA polymerase inhibitors containing a pyrano[3,4-b]indole scaffold is described leading to the discovery of compound 16, a highly potent and selective inhibitor that is active in the replicon system.