Synthesis and structure–activity relationship of 7-azaindole piperidine derivatives as CCR2 antagonists

Synthesis of Deuterium-Labeled CCR2 Antagonist JNJ-26131300, [4-(1H-Indol-3-yl)-piperidin-1-yl]-{1-[3-(3,4,5-trifluoro-phenyl)-acryloyl]-piperidin-4-yl}-acetic acid

Synthesis of multiple deuterium-labeled CCR2 antagonist JNJ-26131300, i.e. [4-(1H-indol-3-yl)-piperidin-1-yl]-{1-[3-(3,4,5-trifluoro-phenyl)-acryloyl]-piperidin-4-yl}-acetic acid is described. First, condensation of indole-D₇ with 4-piperidone produced 3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indole-D₅ , which subsequently underwent catalytic hydrogenation to give 3-piperidin-4-yl-1H-indole-D₅ . Next, bromo-{1-[3-(3,4,5-trifluoro-phenyl)-acryloyl]-piperidin-4-yl}-acetic acid was prepared through multiple steps from 3-(3,4,5-trifluoro-phenyl)-acrylic acid and bromo-piperidin-4-yl-acetic acid ethyl ester. Nucleophilic coupling of 3-piperidin-4-yl-1H-indole-D₅ with bromo-{1-[3-(3,4,5-trifluoro-phenyl)-acryloyl]-piperidin-4-yl}-acetic acid afforded the desired compound [4-(1H-indol-3-yl)-piperidin-1-yl]-{1-[3-(3,4,5-trifluoro-phenyl)-acryloyl]-piperidin-4-yl}-acetic acid-D₅ .

Azaindole therapeutic agents

Azaindole structural framework is an integral part of several biologically active natural and synthetic organic molecules; and several FDA approved drugs for various diseases. In the last decade, quite a number of literature reports appeared describing the pharmacology, biological activity and therapeutic applications of a variety of azaindole molecules. This prompted the organic and medicinal chemistry community to develop novel synthetic methods for various azaindoles and test them for a bioactivity against a variety of biological targets. Herein, we have summarized the biological activity of therapeutically advanced clinical candidates and several preclinical candidate drugs that contain azaindole structural moiety.

7-Azaindole Analogues as Bioactive Agents and Recent Results

Azaindoles have been accepted as important structures having various biological activities in medicinal chemistry in novel drug discovery. Various azaindole derivatives have been used commercially and newer analogues are synthesized continuously. As in literature, azaindole is a very potent moiety, its derivatives displayed a number of biological activities such as kinase inhibitors, cytotoxic agents, anti-angiogenic activity, CRTh2 receptor antagonists, melanin agonists, nicotine agonists, effectiveness in alzheimer disease, cytokinin analogs, Orai inhibitors in asthma and chemokine receptor- 2 (CCR2) antagonists. This review consists of biological activities of various azaindole analogs, reported so far, and their structure activity relations, along with future perspectives in this field.

Structural refinement and prediction of potential CCR2 antagonists through validated multi-QSAR modeling studies

Chemokines trigger numerous inflammatory responses and modulate the immune system. The interaction between monocyte chemoattractant protein-1 and chemokine receptor 2 (CCR2) may be the cause of atherosclerosis, obesity, and insulin resistance. However, CCR2 is also implicated in other inflammatory diseases such as rheumatoid arthritis, multiple sclerosis, asthma, and neuropathic pain. Therefore, there is a paramount importance of designing potent and selective CCR2 antagonists despite a number of drug candidates failed in clinical trials. In this article, 83 CCR2 antagonists by Jhonson and Jhonson Pharmaceuticals have been considered for robust validated multi-QSAR modeling studies to get an idea about the structural and pharmacophoric requirements for designing more potent CCR2 antagonists. All these QSAR models were validated and statistically reliable. Observations resulted from different modeling studies correlated and validated results of other ones. Finally, depending on these QSAR observations, some new molecules were proposed that may exhibit higher activity against CCR2.

Progress in the discovery of CC chemokine receptor 2 antagonists, 2009 - 2012

INTRODUCTION

CC chemokine receptor 2 (CCR2) is a key mediator of the activation and migration of inflammatory monocytes. As such, it has been investigated extensively as a target for therapeutic intervention in a diverse range of diseases.

AREAS COVERED

This article reviews both the patent and peer-reviewed literature on the discovery of CCR2 antagonists from January 2009 to December 2012. Developments have occurred within each of the major chemical families of CCR2 antagonists, and are framed in that context. As has been true historically, a number of the compound families also exhibit substantial activity against the related CC chemokine receptor 5 (CCR5), making them formally CCR2/5-dual antagonists.

EXPERT OPINION

Significant progress continues to be made in identifying novel, potent CCR2 antagonists. In addition, researchers have had success in addressing issues related to selectivity, cardiac safety, and preclinical pharmacokinetics. Establishing proof-of-concept in clinical trials remains the primary challenge for the field.

CCR2 Antagonists for the Treatment of Diseases Associated with Inflammation

The CCR2 and MCP-1 pathway has become one of the most-studied chemokine systems for therapeutic use in inflammatory diseases and conditions. It plays a pivotal role in inflammatory diseases, especially those that are characterized by monocyte-rich infiltration. This chapter reviews the biology of CCR2 and MCP-1, and their roles in diseases and conditions related to inflammation such as rheumatoid arthritis, multiple sclerosis, asthma, obesity, type 2 diabetes, atherosclerosis, nephropathy, cancer, pulmonary fibrosis and pain. Intense drug-discovery efforts over the past 15 years have generated a large number of CCR2 antagonists in diverse structural classes. Mutagenesis studies have elucidated important residues on CCR2 that interact with many classes of these CCR2 antagonists. To facilitate understanding of CCR2 antagonist SAR, a simple pharmacophore model is used to summarize the large number of diverse chemical structures. The majority of published compounds are classified based on their central core structures using this model. Key SAR points in the published literature are briefly discussed for most of the series. Lead compounds in each chemical series are highlighted where information is available. The challenges in drug discovery and development of CCR2 antagonists are briefly discussed. Clinical candidates in various diseases in the public domain are summarized with a brief discussion about the clinical challenges.