Synthesis and biological evaluation of 4-[(3-methyl-3H-imidazol-4-yl)-(2-phenylethynyl-benzyloxy)-methyl]-benzonitrile as novel farnesyltransferase inhibitor

Farnesyltransferase inhibitors (FTIs) have emerged as a novel class of anticancer agents. Analogues of the potent FTI, 4-[3-biphenyl-1-hydroxy-1-(3-methyl-3H-imidazol-4-yl)-prop-2-ynyl]-1-yl-benzonitrile, were synthesized and tested in vitro for their inhibitory activities. The most promising compound identified from this series is analogue 11 that possesses potent enzymatic and cellular activities.     

Synthesis and biological evaluation of 4-[3-biphenyl-2-yl-1-hydroxy-1-(3-methyl-3H-imidazol-4-yl)-prop-2-ynyl]-1-yl-benzonitrile as novel farnesyltransferase inhibitor

Farnesyltransferase inhibitors (FTIs) have emerged as a novel class of anti-cancer agents. Analogues of the potent FTI, 4-[3-biphenyl-1-hydroxy-1-(3-methyl-3H-imidazol-4-yl)-prop-2-ynyl]-1-yl-benzonitrile, were synthesized and tested in vitro for their inhibitory activities. The synthesis and detailed biological data of this series of analogues are presented.     

Synthesis and biological activity of 5-aryl-4-(4-(5-methyl-1H-imidazol-4-yl)piperidin-1-yl)pyrimidine analogs as potent, highly selective, and orally bioavailable NHE-1 inhibitors

A series of potent inhibitors of the sodium hydrogen exchanger-1 (NHE-1) is described. Structure-activity relationships identified the 3-methyl-4-fluoro analog 9t as a highly potent (IC50 = 0.0065 microM) and selective (NHE-2/NHE-1=1400) non-acylguanidine NHE-1 inhibitor. Pharmacokinetic studies showed that compound 9t has an oral bioavailability of 52% and a plasma half life of 1.5 h in rats. Because of its promising potency, selectivity, and a good pharmacokinetic profile, compound 9t was selected for further studies.     

4-Phenyl-4-[1H-imidazol-2-yl]-piperidine derivatives, a novel class of selective delta-opioid agonists

A novel series of 4-phenyl-4-[1H-imidazol-2-yl]-piperidine derivatives has been prepared and their synthesis described herein. In vitro affinities for delta-, mu-, and kappa-opioid receptors, as well as the functional activity in the [(35)S]GTPgammaS assay are reported. The most potent and selective delta-opioid agonist 18a exhibited a K(i) of 18 nM, and was >258-fold and 28-fold selective over mu- and kappa-receptors, respectively; the compound is a full agonist with an EC(50) value of 14 nM.     

Identification ofS-[2-carboxy-1-(1H-imidazol-4-yl)ethyl]-3-mercaptopyruvic acid with a metabolic intermediate betweenS-[2-carboxy-1-(1H-imidazol-4-yl)ethyl]-l-cysteine andS-[2-carboxy-1-(1H-imidazol-4-yl)ethyl]-3-mercaptolactic acid

Summary S-[2-Carboxy-1-(1H-imidazol-4-yl)ethyl]-3-mercaptopyruvic acid (I) was chemically synthesized in 15% yield by incubating a reaction mixture oftrans-urocanic acid and 3-fold excess of 3-mercaptopyruvic acid at 45°C for 6 days. The synthesized compound was characterized by fast-atom-bombardment mass spectrometry and high-voltage paper electrophoresis. CompoundI was identified with a product of an enzymatic reaction ofS-[2-carboxy-1-(1H-imidazol-4-yl)ethyl]-l-cysteine (II) with rat liver homogenate in a phosphate buffer, pH 7.4. CompoundI was degraded toS-[2-carboxy-1-(1H-imidazol-4-yl)ethyl]-3-mercaptolactic acid (III), a compound previously found in human urine [Kinuta et al. (1994) Biochem J 297: 475–478], by incubation with rat liver homogenate. From these results, we suggest that compoundI is a metabolic intermediate for the formation of compoundIII from compoundII. The present pathway follows a formation of compoundII fromS-[2-carboxy-1-(1H-imidazol-4-yl)ethyl] gluthathione [Kinuta et al. (1993) Biochim Biophys Acta 1157: 192–198], a proposed metabolite ofl-histidine.     

Discovery and evaluation of 3-(5-thien-3-ylpyridin-3-yl)-1H-indoles as a novel class of KDR kinase inhibitors

We have discovered 3-(5-thien-3-ylpyridin-3-yl)-1H-indoles as potent inhibitors of KDR kinase activity. This communication details the evolution of this novel class from a potent screening lead of vastly different structure with an emphasis on structural modifications that retained activity and provided improvements in key physical properties. The synthesis and in-depth evaluation of these inhibitors are described.     

1-(1,3-Benzodioxol-5-ylmethyl)-3-[4-(1H-imidazol-1-yl)phenoxy]-piperidine analogs as potent and selective inhibitors of nitric oxide formation

A new series of 1-(1,3-benzodioxol-5-ylmethyl)-3-[4-(1H-Imidazol-1-yl)phenoxy]-piperidine analogs were designed and identified as potent and selective inhibitors of NO formation based both on the crystal structure of a murine iNOS Delta114 monomer domain/ inhibitor complex and inhibition of the NO formation in human A172 cell assays. Compound 12S showed high potency and high iNOS selectivity versus nNOS and eNOS.     

Novel retinoic acid 4-hydroxylase (CYP26) inhibitors based on a 3-(1H-imidazol- and triazol-1-yl)-2,2-dimethyl-3-(4-(phenylamino)phenyl)propyl scaffold

Retinoic acid (RA), the biologically active metabolite of vitamin A, is used medicinally for the treatment of hyperproliferative diseases including dermatological conditions and cancer. The antiproliferative effects of RA have been well documented as well as the limitations owing to toxicity and the development of resistance to RA therapy. RA metabolism inhibitors (RAMBAs or CYP26 inhibitors) are attracting increasing interest as an alternative method for enhancing endogenous levels of retinoic acid in the treatment of hyperproliferative disease. Here the synthesis and inhibitory activity of novel 3-(1H-imidazol- and triazol-1-yl)-2,2-dimethyl-3-(4-(phenylamino)phenyl)propyl derivatives in a MCF-7 CYP26A1 microsomal assay are described. The most promising inhibitor methyl 2,2-dimethyl-3-(4-(phenylamino)phenyl)-3-(1H-1,2,4-triazol-1-yl)propanoate (6) exhibited an IC(50) of 13 nM (compared with standards Liarozole IC(50) 540 nM and R116010 IC(50) 10 nM) and was further evaluated for CYP selectivity using a panel of CYP with >100-fold selectivity for CYP26 compared with CYP1A2, 2C9 and 2D6 observed and 15-fold selectivity compared with CYP3A4. The results demonstrate the potential for further development of these potent inhibitors.     

Discovery of a novel sub-class of ROMK channel inhibitors typified by 5-(2-(4-(2-(4-(1H-Tetrazol-1-yl)phenyl)acetyl)piperazin-1-yl)ethyl)isobenzofuran-1(3H)-one

A sub-class of distinct small molecule ROMK inhibitors were developed from the original lead 1. Medicinal chemistry endeavors led to novel ROMK inhibitors with good ROMK functional potency and improved hERG selectivity. Two of the described ROMK inhibitors were characterized for the first in vivo proof-of-concept biology studies, and results from an acute rat diuresis model confirmed the hypothesis that ROMK inhibitors represent new mechanism diuretic and natriuretic agents.     

Computational validation of 3-ammonio-3-(4-oxido- 1H-imidazol-1-ium-5-yl) propane-1, 1-bis (olate) as a potent anti-tubercular drug against mt-MetAP

The advent of Multi Drug Resistant (MDR) strain of Mycobacterium tuberculosis (TB) necessitated search for new drug targets for the bacterium. It is reported that 3.3% of all new tuberculosis cases had multidrug resistance (MDR-TB) in 2009 and each year, about 0.44 million MDR-TB cases are estimated to emerge and 0.15 million people with MDR-TB die. Keeping such an alarming situation under consideration we wanted to design suitable anti tubercular molecules for new target using computational tools. In the work Methionine aminopeptidase (MetAP) of Mycobacterium tuberculosis was considered as target and three non-toxic phenolic=ketonic compounds were considered as ligands. Docking was done with Flex X and AutoDock 4.2 separately. Ten proven inhibitors of MetAP were collected from literature with their IC50 and were correlated using EasyQSAR to generate QSAR model. Activity of ligands in question was predicted from QSAR. Pharmacophore for each docking was generated using Ligandscout 3.0. Toxicity of the ligands in question was predicted on Mobyle@rpbs portal and Actelion property explorer. Molecular docking with target showed that of all three ligands, 3-ammonio-3-(4-oxido-1H-imidazol-1-ium-5-yl) propane-1, 1-bis (olate) has highest affinity (- 37.5096) and lowest IC50 (4.46 µM). We therefore, propose that -3-ammonio-3-(4-oxido-1H-imidazol-1-ium-5-yl) propane-1,1- bis(olate) as a potent MetAP inhibitor may be a new anti-tubercular drug particularly in the context of Multi Drug Resistant Tuberculosis (MDR-TB).     

Design and synthesis of novel 3-(benzo[d]oxazol-2-yl)-5-(1-(piperidin-4-yl)-1H-pyrazol-4-yl)pyridin-2-amine derivatives as selective G-protein-coupled receptor kinase-2 and -5 inhibitors

G-protein-coupled receptor kinase (GRK)-2 and -5 are emerging therapeutic targets for the treatment of cardiovascular disease. In our efforts to discover novel small molecules to inhibit GRK-2 and -5, a class of compound based on 3-(benzo[d]oxazol-2-yl)-5-(1-(piperidin-4-yl)-1H-pyrazol-4-yl)pyridin-2-amine was identified as a novel hit by high throughput screening campaign. Structural modification of parent benzoxazole scaffolds by introducing substituents on phenyl displayed potent inhibitory activities toward GRK-2 and -5.     

Synthesis and optimization of novel (3S,5R)-5-(2,2-dimethyl-5-oxo-4-phenylpiperazin-1-yl)piperidine-3-carboxamides as orally active renin inhibitors

We report synthesis and optimization of a series of (3S,5R)-5-(2,2-dimethyl-5-oxo-4-phenylpiperazin-1-yl)piperidine-3-carboxamides as renin inhibitors. Chemical modification of ${{\text{P}}_1}^{\prime }$, ${{\text{P}}_2}^{\prime }$ and P₃ portions led to a promising 3,5-disubstituted piperidine 32o showing high renin inhibitory activity and favorable oral exposure in both rats and cynomolgus monkeys with acceptable CYP and hERG current inhibition. Compound 32o exhibited a significant blood pressure lowering effect by oral administration in two hypertensive animal models, double transgenic rats and furosemide pretreated cynomolgus monkeys.     

Identification of a novel, orally bioavailable histamine H(3) receptor antagonist based on the 4-benzyl-(1H-imidazol-4-yl) template

A novel series of histamine H(3) receptor antagonists, based on the 4-benzyl-(1H-imidazole-4-yl) template, incorporating urea and carbamate linkers has been prepared. Compound 3j is a selective H(3) antagonist and demonstrates excellent oral plasma levels in the rat and monkey.     

Histamine H3 and H4 receptor affinity of branched 3-(1H-imidazol-4-yl)propyl N-alkylcarbamates

A series of imidazole-containing (non-)chiral carbamates were tested at human histamine H₃ receptor (H₃R). All compounds displayed K_i values below 100 nM. A trend for a stereoselectivity at human H₃R was observed for the chiral α-branched ligands. Selected compounds were also tested at human histamine H₄ receptor and showed moderate to weak affinities (118–1460 nM).     

Synthesis of novel 3-(1-(1-substituted piperidin-4-yl)-1H-1,2,3-triazol-4-yl)-1,2,4-oxadiazol-5(4H)-one as antifungal agents

A novel series of 1,2,3 triazole compounds possessing 1,2,4 oxadiazole ring were efficiently synthesized. Synthesized compounds were evaluated for their in vitro antifungal activities using standard cup plate method. SAR for the series has been developed by comparing their MIC values with miconazole and fluconazole. Compound 11a from the series was more potent than miconazole against Candida albicans (MIC-20) and Aspergillus flavus (MIC-10) whereas equipotent with miconazole against Fusarium oxysporum (MIC-25) and Aspergillus niger (MIC-12.5). Also compound 11h was more potent than miconazole against Candida albicans (MIC-20) and Aspergillus niger (MIC-10) and equipotent with miconazole against Fusarium oxysporum. Compound 11h was equipotent with fluconazole against Aspergillus niger (MIC-10).     

Discovery of 5-(4-methylpiperazin-1-yl)-2-nitroaniline derivatives as a new class of SIRT6 inhibitors

SIRT6 is a deacetylase of histone H3 and inhibitors of SIRT6 have been thought as potential agents for treatment of diabetes. Herein we report the discovery of a series of new SIRT6 inhibitors containing the skeleton 1-phenylpiperazine. Among them, compound 5-(4-methylpiperazin-1-yl)-2-nitroaniline (6d) is the most potent one, which showed an IC₅₀ value of 4.93 μM against SIRT6 in the Fluor de Lys (FDL) assay. It displayed K_D values of 9.76 μM and 10 μM in surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC) assays, respectively. In selectivity assay, 6d showed no activity against other members of the HDAC family (SIRT1-3 and HDAC1-11) at concentrations up to 200 µM. In a mouse model of type 2 diabetes, 6d could significantly increase the level of glucose transporter GLUT-1, thereby reducing blood glucose. Overall, this study provides a promising lead compound for subsequent drug discovery targeting SIRT6.     

The synthesis and evaluation of a novel class of (E)-3-(1-cyclohexyl-1H-pyrazol-3-yl)-2-methylacrylic acid hepatitis C virus polymerase NS5B inhibitors

Herein we report the identification and evaluation of a novel series of (E)-3-(1-cyclohexyl-1H-pyrazol-3-yl)-2-methylacrylic acid derivatives identified from a deannulation study performed on the reported benzimidazole NS5B inhibitor, 1. This resulted in the identification of (E)-3-(2-(4-((4′-cyano-4-(4-hydroxypiperidine-1-carbonyl)biphenyl-2-yl)methoxy)phenyl)-1-cyclohexyl-1H-imidazol-4-yl)-2-methylacrylic acid (11) as a potent inhibitor of NS5B. Potential pathways for the further optimization of this series are suggested.     

3-(1H-imidazol-4-yl)propyl]guanidines containing furoxan moieties: a new class of H3-antagonists endowed with NO-donor properties

Synthesis and pharmacological characterisation of a series of products obtained by coupling the H(3)-antagonist SKF 91486 through appropriate spacers with the NO-donor 3-phenylfuroxan-4-yloxy and 3-benzenesulfonylfuroxan-4-yloxy moieties, as well as with the corresponding furazan substructures, devoid of NO-donating properties, are reported. All the products were tested for their H(3)-antagonistic and H(2)-agonistic properties on electrically-stimulated guinea-pig ileum segments and guinea-pig papillary muscle, respectively. The whole series of compounds displayed good H(3)-antagonist behaviour and feeble partial H(2)-agonist activity. Among furoxan derivatives, the benzenesulfonyl hybrid 28, a good NO-donor, triggered a dual NO-dependent muscle relaxation and H(3)-antagonistic effect on guinea-pig intestine.     

Synthesis and Fungicidal Activity of 5-Aryl-1-(aryloxyacetyl)-3-(tert-butyl or phenyl)-4-(1H-1,2,4-triazol-1-yl)-4,5-Dihydropyrazole

A series of novel 5-aryl-1-(aryloxyacetyl)-3-(tert-butyl or phenyl)-4-(1H-1,2,4-triazol-1-yl)-4,5-dihydropyrazole 3a-3n were synthesized by the annulation of 2-aryloxyacetohydrazides with 3-aryl-1-t-butyl(or phenyl)-2-(1H-1,2,4-triazol-1-yl)prop-2-en-1-ones(1)in the presence of a catalytic amount of acetic acid.Compounds 2 were obtained by the Knoevenagel reactions of 1-t-butyl(or phenyl)-2-(1H-1,2,4-triazol-1-yl)ethanone(2)with aromatic aldehydes in the presence of piperidine.Their structures were confirmed by IR,1H-NMR,ESIMS,and elemental analyses.The preliminary bioassay indicated that some compounds displayed moderate to excellent fungicidal activity.For example,compounds 31,3m,and 3n possessed100%inhibition against Cercospora arachidicola Hori at the concentration of 50 mg/L.     

3-Imidazolylmethylaminophenylsulfonyltetrahydroquinolines, a novel series of farnesyltransferase inhibitors

Design, synthesis and structure-activity relationship of a series of 3-imidazolylmethylaminophenylsulfonyltetrahydroquinolines as farnesyltransferase inhibitors are presented. A working pharmacophore of inhibiting farnesyltransferase by this series of inhibitors is proposed.