Benzimidazole-based DGAT1 inhibitors with a [3.1.0] bicyclohexane carboxylic acid moiety.

Previously disclosed benzimidazole-based DGAT1 inhibitors containing a cyclohexane carboxylic acid moiety suffer from isomerization at the alpha position of the carboxylic acid group, generating active metabolites which exhibit DGAT1 inhibition comparable to the corresponding parent compounds. In this report, we describe the design, synthesis and profiling of benzimidazole-based DGAT1 inhibitors with a [3.1.0] bicyclohexane carboxylic acid moiety. Our results show that single isomer 3A maintains in vitro and in vivo inhibition against DGAT1. In contrast to previous lead compounds, 3A does not undergo isomerization during in vitro hepatocyte incubation study or in vivo mouse study.

Constraining the amide bond in N-sulfonylated dipeptide VLA-4 antagonists.

The integrin VLA-4 is implicated in several inflammatory disease states. In search of non-peptidic antagonists of VLA-4, rotational constraints were imposed on the amide bond of prototypical N-sulfonylated dipeptide VLA-4 antagonists. By judicious structural modification of the side chains, trisubstituted imidazoles with moderate binding potencies were obtained, for example, 19, VLA-4 IC(50)=237 nM.

Discovery of a Potent and Selective DGAT1 Inhibitor with a Piperidinyl-oxy-cyclohexanecarboxylic Acid Moiety.

We report the discovery of a novel series of DGAT1 inhibitors in the benzimidazole class with a piperdinyl-oxy-cyclohexanecarboxylic acid moiety. This novel series possesses significantly improved selectivity against the A2A receptor, no ACAT1 off-target activity at 10 µM, and higher aqueous solubility and free fraction in plasma as compared to the previously reported pyridyl-oxy-cyclohexanecarboxylic acid series. In particular, 5B was shown to possess an excellent selectivity profile by screening it against a panel of more than 100 biological targets. Compound 5B significantly reduces lipid excursion in LTT in mouse and rat, demonstrates DGAT1 mediated reduction of food intake and body weight in mice, is negative in a 3-strain Ames test, and appears to distribute preferentially in the liver and the intestine in mice. We believe this lead series possesses significant potential to identify optimized compounds for clinical development.

Potent DGAT1 Inhibitors in the Benzimidazole Class with a Pyridyl-oxy-cyclohexanecarboxylic Acid Moiety.

We report the design and synthesis of a series of novel DGAT1 inhibitors in the benzimidazole class with a pyridyl-oxy-cyclohexanecarboxylic acid moiety. In particular, compound 11A is a potent DGAT1 inhibitor with excellent selectivity against ACAT1. Compound 11A significantly reduces triglyceride excursion in lipid tolerance tests (LTT) in both mice and dogs at low plasma exposure. An in vivo study in mice with des-fluoro analogue 10A indicates that this series of compounds appears to distribute in intestine preferentially over plasma. The propensity to target intestine over plasma could be advantageous in reducing potential side effects since lower circulating levels of drug are required for efficacy. However, in the preclinical species, compound 11A undergoes cis/trans epimerization in vivo, which could complicate further development due to the presence of an active metabolite.

VLA-4 antagonists: potent inhibitors of lymphocyte migration.

Circulating lymphocytes normally migrate through extravascular spaces in relatively low numbers as important members of the immunosurveillance process. That is until signals are received by endothelial cells that there is an underlying infection or inflammatory condition. These vascular surface cells in turn overexpress and present ligands to circulating lymphocyte adhesion molecules. Upon encountering this higher density of ligands, lymphocytes, which had been leisurely rolling along the vascular surface, now become more firmly attached, change shape, and migrate through tight junctions to the sites of infection or inflammation. If the initiating events are not resolved and the condition becomes chronic, there can be a sustained extravasation of lymphocytes that can exacerbate the inflammatory condition, which in turn will continue to recruit more inflammatory cells resulting in unwanted tissue destruction. It is for the attenuation of this cycle of sustained inflammatory cell recruitment that very late activating antigen-4 (VLA-4) antagonists are being developed. Most lymphocytes, except neutrophils, express VLA-4 on their surface and they interact with endothelial vascular cell adhesion molecule-1 (VCAM-1). It is this interaction that VLA-4 antagonists are intended to disrupt, thus, putting an end to the cycle of chronic inflammation, which is the hallmark of many diseases. This review will provide an update of VLA-4 antagonists that have appeared since early 2001 and will discuss some of the issues, both positive and negative, that may be encountered in their development.

Substituted tetrahydrofuroyl-1-phenylalanine derivatives as potent and specific VLA-4 antagonists.

A series of substituted tetrahydrofuroyl-1-phenylalanine derivatives was prepared and evaluated as VLA-4 antagonists. Substitution of the alpha carbon of the tetrahydrofuran with aryl groups increased the specificity for VLA-4 versus alpha(4)beta(7) while amide substitution increased the potency of the series without increasing the specificity. Substitution of the beta carbon of the tetrahydrofuran with keto or amino groups slightly improved the specificity for VLA-4 versus alpha(4)beta(7) but with a significant loss in binding affinity for VLA-4.

N-isonicotinoyl-(L)-4-aminophenylalanine derivatives as tight binding VLA-4 antagonists.

A series of isonicotinoyl-(L)-aminophenylalanine derivatives was prepared and evaluated as VLA-4 antagonists. These compounds exhibit subnanomolar binding affinity to VLA-4 and significant off-rates. The interplay between off-rate, protein binding and pharmacokinetics is discussed.

N-Tetrahydrofuroyl-(L)-phenylalanine derivatives as potent VLA-4 antagonists.

Given the proposed involvement of VLA-4 in inflammatory processes, a program to identify orally active VLA-4 antagonists was initiated. Herein, we report the discovery of a N-tetrahydrofuroyl-(L)-phenylalanine derivative (17) and related analogues as potent VLA-4 antagonists with good oral bioavailability.