Discovery and synthesis of novel 4-aminopyrrolopyrimidine Tie-2 kinase inhibitors for the treatment of solid tumors

The synthesis and biological evaluation of novel Tie-2 kinase inhibitors are presented. Based on the pyrrolopyrimidine chemotype, several new series are described, including the benzimidazole series by linking a benzimidazole to the C5-position of the 4-amino-pyrrolopyrimidine core and the ketophenyl series synthesized by incorporating a ketophenyl group to the C5-position. Medicinal chemistry efforts led to potent Tie-2 inhibitors. Compound 15, a ketophenyl pyrrolopyrimidine urea analog with improved physicochemical properties, demonstrated favorable in vitro attributes as well as dose responsive and robust oral tumor growth inhibition in animal models.     

Structure-activity relationship study on a novel series of cyclopentane-containing macrocyclic inhibitors of the hepatitis C virus NS3/4A protease leading to the discovery of TMC435350

SAR analysis performed with a limited set of cyclopentane-containing macrocycles led to the identification of N-[17-[2-(4-isopropylthiazole-2-yl)-7-methoxy-8-methylquinolin-4-yloxy]-13-methyl-2,14-dioxo-3,13-diazatricyclo [13.3.0.0^4,6]octadec-7-ene-4-carbonyl](cyclopropyl)sulfonamide (TMC435350, 32c) as a potent inhibitor of HCV NS3/4A protease (K_i = 0.36 nM) and viral replication (replicon EC₅₀ = 7.8 nM). TMC435350 also displayed low in vitro clearance and high permeability, which were confirmed by in vivo pharmacokinetic studies. TMC435350 is currently being evaluated in the clinics.     

Scaffold oriented synthesis. Part 3: design, synthesis and biological evaluation of novel 5-substituted indazoles as potent and selective kinase inhibitors employing [2+3] cycloadditions

We report the synthesis and biological evaluation of 5-substituted indazoles and amino indazoles as kinase inhibitors. The compounds were synthesized in a parallel synthesis fashion from readily available starting materials employing [2+3] cycloaddition reactions and were evaluated against a panel of kinase assays. Potent inhibitors were identified for numerous kinases such as Rock2, Gsk3β, Aurora2 and Jak2.     

Discovery of thiazolidin-4-one urea analogues as novel multikinase inhibitors that potently inhibit FLT3 and VEGFR2

A series of novel thiazolidine-4-one urea analogues were designed, synthesized and biologically evaluated. The structure-activity relationship (SAR) at several positions of the scaffolds was investigated and its binding mode was analyzed by molecular modeling studies. Compound 17b proved to be the most potent one, and IC₅₀ values against A549 and HT-29 cancer cell lines were 0.65?μM and 0.11?μM, respectively. The results of kinase profile demonstrated that compound 17b is a multikinase inhibitor that potently inhibits FLT3 (IC₅₀?=?8.6?nM) and VEGFR2 (IC₅₀?=?18.7?nM). The results of real-time live-cell imaging indicated that compound 17b showed excellent cytotoxicity and anti-proliferative activity against HT-29 cancer cells in a time- and dose-dependent manner, which was significantly potent than that of Cabozantinib. In addition, in vitro antitumor activity was associated with inducing cancer cell apoptosis and suppression of cancer cell migration.     

Design and synthesis of novel 2-pyridone peptidomimetic falcipain 2/3 inhibitors

The structure-based design, chemical synthesis and in vitro activity evaluation of various falcipain inhibitors derived from 2-pyridone are reported. These compounds contain a peptidomimetic binding determinant and a Michael acceptor terminal moiety capable of deactivating the cysteine protease active site.     

Scaffold oriented synthesis. Part 4: design, synthesis and biological evaluation of novel 5-substituted indazoles as potent and selective kinase inhibitors employing heterocycle forming and multicomponent reactions

We report the synthesis and biological evaluation of 5-substituted indazoles as kinase inhibitors. The compounds were synthesized in a parallel synthesis fashion from readily available starting materials employing heterocycle forming and multicomponent reactions and were evaluated against a panel of kinase assays. Potent inhibitors were identified for Gsk3β, Rock2, and Egfr.     

Novel pyrrolo[2,1-f][1,2,4]triazin-4-amines: Dual inhibitors of EGFR and HER2 protein tyrosine kinases

A novel series of 5-((4-aminopiperidin-1-yl)methyl)-pyrrolo[2,1-f][1,2,4]triazin-4-amines with small aniline substituents at the C4 position were optimized for dual EGFR and HER2 protein tyrosine kinase inhibition. Compound 8l exhibited promising oral efficacy in both EGFR and HER2-driven human tumor xenograft models.     

Design and optimization of a series of 4-(3-azabicyclo[3.1.0]hexan-3-yl)pyrimidin-2-amines: Dual inhibitors of TYK2 and JAK1

Herein, we disclose a new series of TYK2/ JAK1 inhibitors based upon a 3.1.0 azabicyclic substituted pyrimidine scaffold. We illustrate the use of structure-based drug design for the initial design and subsequent optimization of this series of compounds. One advanced example 19 met program objectives for potency, selectivity and ADME, and demonstrated oral activity in the adjuvant-induced arthritis rat model.     

Unveiling novel 2-cyclopropyl-3-ethynyl-4-(4-fluorophenyl)quinolines as GPCR ligands via PI3-kinase/PAR-1 antagonism and platelet aggregation valuations; development of a new class of anticancer drugs with thrombolytic effects

In the present study, novel 2-cyclopropyl-3-ethynyl-4-(4-fluorophenyl) quinolines (4a-l) were recognized and evaluated as G-Protein Coupled Receptor (GPCR) ligands through molecular evaluations. Thrombin mediates adhesion of mast cell, a type of cell abundantly found in connective tissue and releasing histamine and other substances during inflammatory and allergic reactions, through phosphoinositol 3-kinase pathway. With this background, as preliminary, 4a-l are resolute to be potential leads, designated from their effective phosphoinositol 3-kinase (PI3-Kinase) inhibition potentials, best-docked scores, comparative ligand efficiency, and significant structural attributes evaluated by ab initio simulations. Since thrombin is one of the main reason for various cancer invasion in association with PI3Kinase, a thrombolytic potential of the compounds also analyzed. The experimental in vitro studies confirmed the significant enhancement as PI3Kinase inhibitors and appreciable enhancement in MTT assay of breast and skin cancer cell lines. Significantly, acetophenone substituent in the quinoline scaffold could be coherent to note the significant binding affinity to all the evaluated drug targets.     

Novel 3-methylindoline inhibitors of EZH2: Design,synthesis and SAR

EZH2 (enhancer of zeste homologue 2) is the catalytic subunit of the polycomb repressive complex 2 (PRC2) that catalyzes the methylation of lysine 27 of histone H3 (H3K27). Dysregulation of EZH2 activity is associated with several human cancers and therefore EZH2 inhibition has emerged as a promising therapeutic target. Several small molecule EZH2 inhibitors with different chemotypes have been reported in the literature, many of which use a bicyclic heteroaryl core. Herein, we report the design and synthesis of EZH2 inhibitors containing an indoline core. Partial saturation of an indole to an indoline provided lead compounds with nanomolar activity against EZH2, while also improving solubility and oxidative metabolic stability.     

2,7-Pyrrolo[2,1-f][1,2,4]triazines as JAK2 inhibitors: modification of target structure to minimize reactive metabolite formation

The JAK2/STAT pathway has important roles in hematopoiesis. With the discovery of the JAK2 V617F mutation and its presence in many patients with myeloproliferative neoplasms, research in the JAK2 inhibitor arena has dramatically increased. We report a novel series of potent JAK2 inhibitors containing a 2,7-pyrrolotriazine core. To minimize potential drug-induced toxicity, targets were analyzed for the ability to form a glutathione adduct. Glutathione adduct formation was decreased by modification of the aniline substituent at C2.     

Piperazine: An excellent catalyst for the synthesis of 2-amino-3-cyano-4H-pyrans derivatives in aqueous medium

An improved, forthright, and highly efficient one-pot synthesis of a wide range of pharmaceutically exciting diverse kind of functionalized 2-amino-3-cyano-4H-pyrans and especially bis-pyrans compounds is developed using piperazine as a low-cost and environmentally benign commercially available basic catalyst in aqueous media. The attractive features of this process are simple procedure, short reaction times, high yields, no column chromatographic separation and commercial availability and recyclability of the catalyst. Also, piperazine can catalyze the synthesis of the target compounds on a larger scale. Furthermore, rational mechanism was suggested via GC-Mass analysis of the trapped intermediates.     

Design,synthesis and biological evaluation of 5-amino-4-(1H-benzoimidazol-2-yl)-phenyl-1,2-dihydro-pyrrol-3-ones as inhibitors of protein kinase FGFR1

Fibroblast growth factor receptor 1 (FGFR1) plays an important role in tumorigenesis and is therefore an attractive target for anticancer therapy. Using molecular docking approach we have identified inhibitor of FGFR1 belonging to 5-amino-4-(1H-benzoimidazol-2-yl)-phenyl-1,2-dihydro-pyrrol-3-ones with IC₅₀ value of 3.5 μM. A series of derivatives of this chemical scaffold has been synthesized and evaluated for inhibition of FGFR1 kinase activity. It was revealed that the most promising compounds 5-amino-1-(3-hydroxy-phenyl)-4-(6-methyl-1H-benzoimidazol-2-yl)-1,2-dihydro-pyrrol-3-one and 5-amino-4-(1H-benzoimidazol-2-yl)-1-(3-hydroxy-phenyl)-1,2-dihydro-pyrrol-3-one inhibit FGFR1 with IC₅₀ values of 0.63 and 0.32 μM, respectively, and posses antiproliferative activity against KG1 myeloma cell line with IC₅₀ values of 5.6 and 9.3 μM. Structure–activity relationships have been studied and binding mode of this chemical class has been proposed.     

Structure-based drug design of 1,3,5-triazine and pyrimidine derivatives as novel FGFR3 inhibitors with high selectivity over VEGFR2

Fibroblast growth factor receptor 3 (FGFR3) is an attractive therapeutic target for the treatment of bladder cancer. We identified 1,3,5-triazine derivative 18b and pyrimidine derivative 40a as novel structures with potent and highly selective FGFR3 inhibitory activity over vascular endothelial growth factor receptor 2 (VEGFR2) using a structure-based drug design (SBDD) approach. X-ray crystal structure analysis suggests that interactions between 18b and amino acid residues located in the solvent region (Lys476 and Met488), and between 40a and Met529 located in the back pocket of FGFR3 may underlie the potent FGFR3 inhibitory activity and high kinase selectivity over VEGFR2.     

7-(4H-1,2,4-Triazol-3-yl)benzo[c][2,6]naphthyridines: a novel class of Pim kinase inhibitors with potent cell antiproliferative activity

A novel class of pan-Pim kinase inhibitors was designed by modifying the CK2 inhibitor CX-4945. Introduction of a triazole or secondary amide functionality on the C-7 position and 2'-halogenoanilines on C-5 resulted in potent inhibitors of the Pim-1 and Pim-2 isoforms, with many analogs active at single digit nanomolar concentrations. The molecules inhibited the phosphorylation at Serine 112 of the apoptosis effector BAD, and had potent antiproliferative effects on the AML cell line MV-4-11 (IC(50) <30 nM). This work delivers an excellent lead-optimization platform for Pim targeting anticancer therapies.     

3-(2-Methoxytetrahydrofuran-2-yl)pyrazoles: a novel class of potent, selective cyclooxygenase-2 (COX-2) inhibitors

A series of 3-(2-methoxytetrahydrofuran-2-yl)pyrazoles (4–10) was synthesized. The compounds were evaluated for their ability to inhibit cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) activity in human whole blood (HWB). The compound, 5-(4-methanesulfonylphenyl)-3-(2-methoxytetrahydrofuran-2-yl)-1-p-tolyl-1H-pyrazole 5 showed potent and selective COX-2 inhibition (IC₅₀ for COX-1: >100 μM and COX-2: 1.2 μM).     

Discovery of novel P2 substituted 4-biaryl proline inhibitors of hepatitis C virus NS3 serine protease

Inhibitors of hepatitis C virus NS3 serine protease often incorporate a large P2 moiety to interact with the surface of the enzyme while shielding part of the catalytic triad. This feature is important in many inhibitors in order to have the necessary potency needed for efficacy. In this Letter we explore some new P2 motifs to further exploit this region of the enzyme. In a continuing effort to replace the often found 4-hydroxyproline P2 core found in the majority of inhibitors for this target, various directly attached aryl derivatives were evaluated. Of these, the 2,4-disubstituted thiazole core proved to be the most interesting. SAR around this motif has lead to compounds with K_i’s in the high picomolar range and provided cellular potencies in the single digit nM range.     

Design and synthesis of novel small molecule CCR2 antagonists: Evaluation of 4-aminopiperidine derivatives

A novel N-(2-oxo-2-(piperidin-4-ylamino)ethyl)-3-(trifluoromethyl)benzamide series of human CCR2 chemokine receptor antagonists was identified. With a pharmacophore model based on known CCR2 antagonists a new core scaffold was designed, analogues of it synthesized and structure–affinity relationship studies derived yielding a new high affinity CCR2 antagonist N-(2-((1-(4-(3-methoxyphenyl)cyclohexyl)piperidin-4-yl)amino)-2-oxoethyl)-3-(trifluoromethyl)benzamide.     

Design,synthesis, and evaluation of novel 4-amino-2-(4-benzylpiperazin-1-yl)methylbenzonitrile compounds as Zika inhibitors

The prevalence of Zika virus (ZIKV) has become widespread in recent years. ZIKV infection is associated with severe congenital CNS malformations in both newborns and adults. However, neither vaccines nor therapeutics are available to control ZIKV infection until now. We started by hit screening our in-house small molecule library, then designed, synthesized, and evaluated a new class of 1, 4-bibenzylsubstituted piperazine derivatives for their cytopathic effect (CPE) protection effect in a ZIKV-infected Vero E6 cellular assay. A preliminary structure–activity relationship study identified five novel 4-amino-2-(4-benzylpiperazin-1-yl)methylbenzonitrile analogs with obvious CPE reduction effects against ZIKV at micromolar concentrations. Moreover, compound 3p exerted a significant antiviral effect on both Zika RNA replication and virus protein expression in a dose-dependent manner at low micromolar concentrations. This study demonstrated the potential of a novel 4-amino-2-(4-benzylpiperazin-1-yl)methylbenzonitrile scaffold for the development of anti-ZIKV candidates.     

Design,synthesis of novel isoindoline hybrids as COX-2 inhibitors: Anti-inflammatory,analgesic activities and docking study

A group of novel isoindoline hybrids incorporating oxime, hydrazone, pyrazole, chalcone or aminosulfonyl pharmacophores (9–14) was designed and characterized by spectral data and elemental analyses results. All newly synthesized compounds were evaluated as COX-2 inhibitors, anti-inflammatory and analgesic agents. Six hybrid derivatives (10b, 10c, 11a, 11d, 13, 14) were moderate COX-2 inhibitors (IC₅₀ = 0.11–0.18 µM) close to standard celecoxib (IC₅₀ = 0.09 µM). The most active compounds showed outstanding in vivo anti-inflammatory activity (% edema inhibition = 41.7–50, 1 h; 40.7–67.4, 3 h; 20–46.7, 6 h) better than reference drug diclofenac (% edema inhibition = 29.2, 1 h; 22.2, 3 h; 20, 6 h). Most compounds showed significant peripheral and/or central analgesic activity. The moderate selective COX-2 inhibitor; dimethoxychalcone 11d (SI = 103) displayed excellent anti-inflammatory activity (% edema inhibition = 45.8–59.3) and increased thermal pain threshold (50–92.85%) comparable to piroxicam (75%). Molecular docking studies have been established.