Discovery and characterization of novel TRPML1 agonists.

Screening a library of >100,000 compounds identified the substituted tetrazole compound 1 as a selective TRPML1 agonist. Both enantiomers of compound 1 were separated and profiled in vitro and in vivo. Their selectivity, ready availability and CNS penetration should enable them to serve as the tool compounds of choice in future TRPML1 channel activation studies. SAR studies on conformationally locked macrocyclic analogs further improved the TRPML1 agonist potency while retaining the selectivity.

Discovery of oxazoline enhancers of cellular progranulin release.

Phenotypic screening of an annotated small molecule library and initial SAR studies identified compound 2 as a robust enhancer of progranulin secretion. Detailed SAR development on conformationally restricted carbamate isosteres led to the identification of compound 60 with a 3-fold improvement in BV-2 potency and a 9-fold decrease in hERG inhibition over compound 2, substantially improving this important margin of safety relative to compound 2.

Discovery of quinuclidine modulators of cellular progranulin.

Phenotypic screening of an annotated small molecule library identified the quinuclidine tetrahydroisoquinoline solifenacin (1) as a robust enhancer of progranulin secretion with single digit micromolar potency in a murine microglial (BV-2) cell line. Subsequent SAR development led to the identification of 29 with a 38-fold decrease in muscarinic receptor antagonist activity and a 10-fold improvement in BV-2 potency.

Intestinal serine protease inhibition increases FGF21 and improves metabolism in obese mice.

Trypsin is the major serine protease responsible for intestinal protein digestion. An inhibitor, camostat (CS), reduced weight gain, hyperglycemia, and dyslipidemia in obese rats; however, the mechanisms for these are largely unknown. We reasoned that CS creates an apparent dietary protein restriction, which is known to increase hepatic fibroblast growth factor 21 (FGF21). Therefore, metabolic responses to CS and a gut-restricted CS metabolite, FOY-251, were measured in mice. Food intake, body weight, blood glucose, branched-chain amino acids (LC/MS), hormone levels (ELISA), liver pathology (histology), and transcriptional changes (qRT-PCR) were measured in ob/ob, lean and diet-induced obese (DIO) C57BL/6 mice. In ob/ob mice, CS in chow (9-69 mg/kg) or FOY-251 (46 mg/kg) reduced food intake and body weight gain to a similar extent as pair-fed mice. CS decreased blood glucose, liver weight, and lipidosis and increased FGF21 gene transcription and plasma levels. In lean mice, CS increased liver FGF21 mRNA and plasma levels. Relative to pair feeding, FOY-251 also increased plasma FGF21 and induced liver FGF21 and integrated stress response (ISR) transcription. In DIO mice, FOY-251 (100 mg/kg po) did not alter peak glucose levels but reduced the AUC of the glucose excursion in response to an oral glucose challenge. FOY-251 increased plasma FGF21 levels. In addition to previously reported satiety-dependent (cholecystokinin-mediated) actions, intestinal trypsin inhibition engages non-satiety-related pathways in both leptin-deficient and DIO mice. This novel mechanism improves metabolism by a liver-integrated stress response and increased FGF21 expression levels in mice. NEW & NOTEWORTHY Trypsin inhibitors, including plant-based consumer products, have long been associated with metabolic improvements. Studies in the 1980s and 1990s suggested this was due to satiety hormones and caloric wasting by loss of protein and fatty acids in feces. This work suggests an entirely new mechanism based on the lower amounts of digested protein available in the gut. This apparent protein reduction may cause beneficial metabolic adaptation by the intestinal-liver axis to perceived nutrient stress.

Discovery of a GPR40 Superagonist: The Impact of Aryl Propionic Acid α-Fluorination.

GPR40 is a G-protein-coupled receptor which mediates fatty acid-induced glucose-stimulated insulin secretion from pancreatic beta cells and incretion release from enteroendocrine cells of the small intestine. GPR40 full agonists exhibit superior glucose lowering compared to partial agonists in preclinical species due to increased insulin and GLP-1 secretion, with the added benefit of promoting weight loss. In our search for potent GPR40 full agonists, we discovered a superagonist which displayed excellent in vitro potency and superior efficacy in the Gαs-mediated signaling pathway. Most synthetic GPR40 agonists have a carboxylic acid headgroup, which may cause idiosyncratic toxicities, including drug-induced-liver-injury (DILI). With a methyl group and a fluorine atom substituted at the α-C of the carboxylic acid group, 19 is not only highly efficacious in lowering glucose and body weight in rodent models but also has a low DILI risk due to its stable acylglucuronide metabolite.

The discovery of novel cyclohexylamide CCR2 antagonists.

As a result of further SAR studies on a piperidinyl piperidine scaffold, we report the discovery of compound 44, a potent, orally bioavailable CCR2 antagonist. While having some in vitro hERG activity, this molecule was clean in an in vivo model of QT prolongation. In addition, it showed excellent efficacy when dosed orally in a transgenic murine model of acute inflammation.

Direct dehydrative cross-coupling of tautomerizable heterocycles with alkynes via Pd/Cu-catalyzed phosphonium coupling.

The first chemoselective direct dehydrative cross-coupling of tautomerizable heterocycles with alkynes has been achieved via C-H/C-OH bond activations with direct C(sp(2))-C(sp) bond formation, which is in line with ideal synthesis using readily available materials.

Recent advances in the development of selective androgen receptor modulators.

BACKGROUND: The androgens testosterone and its more potent tissue metabolite 5-alpha-dihydrotesterone regulate diverse physiological process involving both reproductive and non-reproductive functions. Most of the signaling effects of androgens are mediated through the androgen receptor (AR), a member of the nuclear receptor superfamily of transcription factors. The AR has been a target for drug development focused on the treatment of pathological conditions arising from abnormal androgen levels or altered target tissue responsiveness, the improvement of physical performance and the regulation of male fertility. The primary focus for drug design has been the synthesis of chemicals to regulate the transcriptional activity of AR based on the structural and functional properties of the ligands, with a recent preference for selectively anabolic non-steroidals. A new class of molecules targeting androgen receptors called selective androgen receptor modulators is being developed, analogous to the clinically successful and at present marketed selective estrogen receptor modulators. OBJECTIVE/METHODS: This article highlights and reviews research advances in this field that have been published in patent literature since 2003. RESULTS/CONCLUSION: The structural diversity of selective androgen receptor modulators has dramatically increased. Several compounds have emerged as clinical and preclinical candidates.

beta-Alkylthio indolyl carbinols: potent nonsteroidal antiandrogens with oral efficacy in a prostate cancer model.

Through an in vivo screening model, we developed the in vivo SAR of beta-alkylthio indolyl carbinols. Through these efforts we identified a compound with potent oral in vivo efficacy in both immature and mature rat prostate weight reduction models and in a murine xenograft prostate cancer model.

Synthesis of potent and tissue-selective androgen receptor modulators (SARMs): 2-(2,2,2)-Trifluoroethyl-benzimidazole scaffold.

The synthesis and in vivo SAR of 2-(2,2,2)-trifluoroethyl-benzimidazoles are described. Prostate antagonism and/or levator ani agonism can be modulated by varying the substitution at the 2-position of 5,6-dichloro-benzimidazoles. Potent androgen agonists on the muscle were discovered that strongly bind to the androgen receptor (2-17 nM) and show potent in vivo efficacy (0.03-0.11 mg/day). True SARMs showing both prostate antagonism and levator ani agonism were revealed.

2-(2,2,2-Trifluoroethyl)-5,6-dichlorobenzimidazole derivatives as potent androgen receptor antagonists.

The synthesis and in vivo SAR of N-benzyl, N-aceto, and N-ethylene ether derivatives of 2-(2,2,2-trifluoroethyl)-5,6-dichloro-benzimidazole as novel androgen receptor antagonists are described. SAR studies led to the discovery of 4-bromo-benzyl benzimidazole 17 as a more potent androgen receptor antagonist in the rat prostate (ID(50)=0.13mg/day), compared with bicalutamide (ID(50)=0.23mg/day).

The discovery of a potent orally efficacious indole androgen receptor antagonist through in vivo screening.

A series of novel 2-(1H-indol-2-yl)-propan-2-ols have been designed, synthesized, and screened for their ability to inhibit testosterone-induced prostate weight increases in immature rats. Through the use of this paradigm, we were able to identify compounds that exhibited in vivo potency equal to that of the marketed antiandrogen Casodex when orally administered.

Synthesis and SAR of potent and selective androgen receptor antagonists: 5,6-Dichloro-benzimidazole derivatives.

The synthesis and in vivo SAR of 5,6-dichloro-benzimidazole derivatives as novel selective androgen receptor antagonists are described. During screening of 2-alkyl benzimidazoles, it was found that a trifluoromethyl group greatly enhances antagonist activity in the prostate. Benzimidazole 1 is a potent AR antagonist in the rat prostate (ID50 = 0.15 mg/day).

A bioisosteric approach to the discovery of indole carbinol androgen receptor ligands.

Two potential bioisosteres of the nonsteroidal antiandrogen bicalutamide, an imidazolidinone and an indole, were synthesized and tested for their androgen receptor binding. Indole was discovered to be a suitable bioisostere for the acyl anilide moiety in the parent compound. Several analogs in the indole series were found to be 10-fold better than bicalutamide in binding to the recombinant androgen receptor binding domain.

Asymmetric aza-Mannich reactions of sulfinimines: scope and application to the total synthesis of a bromopyrrole alkaloid.

[reaction: see text] An asymmetric intermolecular aza variant of the Mannich reaction is reported utilizing chiral sulfinimine anions as the nucleophile and N-sulfonyl aldimines as the electrophilic component. A wide range of nucleophiles and electrophiles are tolerated by the reaction conditions, delivering the condensation products in good to excellent yield with a high degree of stereocontrol. Application of this methodology to the total synthesis of a natural product is reported.

Silicon-directed oxa-Pictet-Spengler cyclization and an unusual dimerization of 2-trimethylsilanyl tryptophols.

The tetrahydro-pyrano[3,4-b]indoles 6 were synthesized from 2-(2-trimethylsilanyl-1H-indol-3-yl)-ethanols 5 and various ketones or aldehydes through silicon-directed oxa-Pictet-Spengler cyclizations. An unusual reaction led to the dimeric products 7 when some of 5 was treated with acetone using BF(3) as the catalyst.

Structure-activity relationships of N-acyl pyrroloquinolone PDE-5 inhibitors.

The discovery of the potent and selective PDE-5 inhibitory activity of a pyrroloquinolone scaffold prompted us to explore the SAR of its acyl derivatives. During the course of these studies, three structural series were found with K(i) values for PDE-5 in the subnanomolar range. Systematic modification of one of these leads produced a compound with excellent selectivity for PDE-5 over other phosphodiesterases and oral bioavailability of 15% in male rats. This compound also displayed in vivo efficacy in an anesthetized canine model of erection when dosed intravenously.

Furoyl and benzofuroyl pyrroloquinolones as potent and selective PDE5 inhibitors for treatment of erectile dysfunction.

Synthesis of furoyl and benzofuroyl pyrroloquinolones as potent and selective PDE5 inhibitors was reported. Their in vitro potencies in inhibiting PDE5 and selectivity in inhibiting other PDE isozymes (PDE1-4 and PDE6) were evaluated. Some of these compounds are more potent than sildenafil with better selectivity toward PDE1 and PDE6. Incorporation of solublizing groups resulted in bioavailable analogues. Selected compounds showed in vivo efficacy in anesthetized dog model for penile erection.