Discovery of BMS-753426: A Potent Orally Bioavailable Antagonist of CC Chemokine Receptor 2.

To improve the metabolic stability profile of BMS-741672 (1a), we undertook a structure-activity relationship study in our trisubstituted cyclohexylamine series. This ultimately led to the identification of 2d (BMS-753426) as a potent and orally bioavailable antagonist of CCR2. Compared to previous clinical candidate 1a, the tert-butyl amine 2d showed significant improvements in pharmacokinetic properties, with lower clearance and higher oral bioavailability. Furthermore, compound 2d exhibited improved affinity for CCR5 and good activity in models of both monocyte migration and multiple sclerosis in the hCCR2 knock-in mouse. The synthesis of 2d was facilitated by the development of a simplified approach to key intermediate (4R)-9b that deployed a stereoselective reductive amination which may prove to be of general interest.

Use of a Conformational-Switching Mechanism to Modulate Exposed Polarity: Discovery of CCR2 Antagonist BMS-741672.

We encountered a dilemma in the course of studying a series of antagonists of the G-protein coupled receptor CC chemokine receptor-2 (CCR2): compounds with polar C3 side chains exhibited good ion channel selectivity but poor oral bioavailability, whereas compounds with lipophilic C3 side chains exhibited good oral bioavailability in preclinical species but poor ion channel selectivity. Attempts to solve this through the direct modulation of physicochemical properties failed. However, the installation of a protonation-dependent conformational switching mechanism resolved the problem because it enabled a highly selective and relatively polar molecule to access a small population of a conformer with lower polar surface area and higher membrane permeability. Optimization of the overall properties in this series yielded the CCR2 antagonist BMS-741672 (7), which embodied properties suitable for study in human clinical trials.

Discovery of a Potent and Orally Bioavailable Dual Antagonist of CC Chemokine Receptors 2 and 5.

We describe the hybridization of our previously reported acyclic and cyclic CC chemokine receptor 2 (CCR2) antagonists to lead to a new series of dual antagonists of CCR2 and CCR5. Installation of a γ-lactam as the spacer group and a quinazoline as a benzamide mimetic improved oral bioavailability markedly. These efforts led to the identification of 13d, a potent and orally bioavailable dual antagonist suitable for use in both murine and monkey models of inflammation.

Developing Adnectins that target SRC co-activator binding to PXR: a structural approach toward understanding promiscuity of PXR.

The human pregnane X receptor (PXR) is a promiscuous nuclear receptor that functions as a sensor to a wide variety of xenobiotics and regulates expression of several drug metabolizing enzymes and transporters. We have generated "Adnectins", derived from 10th fibronectin type III domain ((10)Fn3), that target the PXR ligand binding domain (LBD) interactions with the steroid receptor co-activator-1 (SRC-1) peptide, displacing SRC-1 binding. Adnectins are structurally homologous to the immunoglobulin superfamily. Three different co-crystal structures of PXR LBD with Adnectin-1 and CCR1 (CC chemokine receptor-1) antagonist Compound-1 were determined. This structural information was used to modulate PXR affinity for a related CCR1 antagonist compound that entered into clinical trials for rheumatoid arthritis. The structures of PXR with Adnectin-1 reveal specificity of Adnectin-1 in not only targeting the interface of the SRC-1 interactions but also engaging the same set of residues that are involved in binding of SRC-1 to PXR. Substituting SRC-1 with Adnectin-1 does not alter the binding conformation of Compound-1 in the ligand binding pocket. The structure also reveals the possibility of using Adnectins as crystallization chaperones to generate structures of PXR with compounds of interest.

Discovery of the CCR1 antagonist, BMS-817399, for the treatment of rheumatoid arthritis.

High-affinity, functionally potent, urea-based antagonists of CCR1 have been discovered. Modulation of PXR transactivation has revealed the selective and orally bioavailable CCR1 antagonist BMS-817399 (29), which entered clinical trials for the treatment of rheumatoid arthritis.

The discovery of BMS-457, a potent and selective CCR1 antagonist.

A series of compounds which exhibited good human CCR1 binding and functional potency was modified resulting in the discovery of a novel series of high affinity, functionally potent antagonists of the CCR1 receptor. Issues of PXR activity, ion-channel potency, and poor metabolic stability were addressed by the addition of a hydroxyl group to an otherwise lipophilic area in the molecule resulting in the discovery of preclinical candidate BMS-457 for the treatment of rheumatoid arthritis.

gamma-Lactams as glycinamide replacements in cyclohexane-based CC chemokine receptor 2 (CCR2) antagonists.

We describe the design, synthesis, and evaluation, of gamma-lactams as glycinamide replacements within a series of di- and trisubstituted cyclohexane CCR2 antagonists. The lactam-containing trisubstituted cyclohexanes proved to be more potent than the disubstituted analogs, as trisubstituted analog, lactam 13, displayed excellent activity (CCR2 binding IC(50)=1.0 nM and chemotaxis IC(50) = 0.5 nM) and improved metabolic stability over its parent glycinamide.

From rigid cyclic templates to conformationally stabilized acyclic scaffolds. Part II: Acyclic replacements for the (3S)-3-benzylpiperidine in a series of potent CCR3 antagonists.

Conformational analysis of the 3-benzylpiperidine in CCR3 antagonist clinical candidate 1 (BMS-639623) predicts that the benzylpiperidine may be replaced by acyclic, conformationally stabilized, anti-1,2-disubstituted phenethyl- and phenpropylamines. Ab initio calculations, enantioselective syntheses, and evaluation in CCR3 binding and chemotaxis assays of anti-1-methyl-2-hydroxyphenethyl- and phenpropylamine-containing CCR3 antagonists support this conformational correlation.

From rigid cyclic templates to conformationally stabilized acyclic scaffolds. Part I: the discovery of CCR3 antagonist development candidate BMS-639623 with picomolar inhibition potency against eosinophil chemotaxis.

Conformational analysis of trans-1,2-disubstituted cyclohexane CCR3 antagonist 2 revealed that the cyclohexane linker could be replaced by an acyclic syn-alpha-methyl-beta-hydroxypropyl linker. Synthesis and biological evaluation of mono- and disubstituted propyl linkers support this conformational correlation. It was also found that the alpha-methyl group to the urea lowered protein binding and that the beta-hydroxyl group lowered affinity for CYP2D6. Ab initio calculations show that the alpha-methyl group governs the spatial orientation of three key functionalities within the molecule. alpha-Methyl-beta-hydroxypropyl urea 31 with a chemotaxis IC(50)=38 pM for eosinophils was chosen to enter clinical development for the treatment of asthma.

Discovery of CC chemokine receptor-3 (CCR3) antagonists with picomolar potency.

Starting with our previously described(20) class of CC chemokine receptor-3 (CCR3) antagonist, we improved the potency by replacing the phenyl linker of 1 with a cyclohexyl linker and by replacing the 4-benzylpiperidine with a 3-benzylpiperidine. The resulting compound, 32, is a potent and selective antagonist of CCR3. SAR studies showed that the 3-acetylphenyl urea of 32 could be replaced with heterocyclic ureas or heterocyclic-substituted phenyl ureas and still maintain the potency (inhibition of eotaxin-induced chemotaxis) of this class of compounds in the low-picomolar range (IC(50) = 10-60 pM), representing some of the most potent CCR3 antagonists reported to date. The potency of 32 for mouse CCR3 (chemotaxis IC(50) = 41 nM) and its oral bioavailability in mice (20% F ) were adequate to assess the efficacy in animal models of allergic airway inflammation. Oral administration of 32 reduced eosinophil recruitment into the lungs in a dose-dependent manner in these animal models. On the basis of its overall potency, selectivity, efficacy, and safety profile, the benzenesulfonate salt of 32, designated DPC168, entered phase I clinical trials.

Beyond U0126. Dianion chemistry leading to the rapid synthesis of a series of potent MEK inhibitors.

Employing phenylmalonitrile dianion chemistry, a large number of analogues of MEK inhibitor lead SH053 (IC(50)=140 nM) were rapidly synthesized leading to single digit nM inhibitors, displaying submicromolar AP-1 transcription inhibition in COS-7 cells. Compound 41, exhibiting a MEK IC(50)=12 nM showed ip activity in a TPA-induced ear edema model with an ED(50)=5 mg/kg.

Discovery of N-propylurea 3-benzylpiperidines as selective CC chemokine receptor-3 (CCR3) antagonists.

The discovery of novel and selective small molecule antagonists of the CC Chemokine Receptor-3 (CCR3) is presented. Simple conversion from a 4- to 3-benzylpiperidine gave improved selectivity for CCR3 over the serotonin 5HT(2A) receptor. Chiral resolution and exploration of mono- and disubstitution of the N-propylurea resulted in several 3-benzylpiperidine N-propylureas with CCR3 binding IC(50)s under 5 nM. Data from in vitro calcium mobilization and chemotaxis assays for these compounds ranged from high picomolar to low nanomolar EC(50)s and correlated well with antagonist binding IC(50)s.

CCR3 antagonists: a potential new therapy for the treatment of asthma. Discovery and structure-activity relationships.

CCR3 antagonist leads with IC(50) values in the microM range were converted into low nM binding compounds that displayed in vitro inhibition of human eosinophil chemotaxis induced by human eotaxin. In particular, 4-benzylpiperidin-1-yl-n-propylureas and erythro-3-(4-benzyl-2-(alpha-hydroxyalkyl)piperidin-1-yl)-n-propylureas (obtained via Beak reaction of N-BOC-4-benzylpiperidine) exhibited single digit nanomolar IC(50) values for CCR3.