Synthesis of 2‐(2‐oxo‐2H‐chromen‐4‐yl)acetamides as potent acetylcholinesterase inhibitors and molecular insights into binding interactions

Sixteen novel coumarin‐based compounds are reported as potent acetylcholinesterase (AChE) inhibitors. The most active compound in this series, 5a (IC₅₀ 0.04 ± 0.01 µM), noncompetitively inhibited AChE with a higher potency than tacrine and galantamine. Compounds 5d , 5j , and 5 m showed a moderate antilipid peroxidation activity. The compounds showed cytotoxicity in the same range as the standard drugs in HEK‐293 cells. Molecular docking demonstrated that 5a acted as a dual binding site inhibitor. The coumarin moiety occupied the peripheral anionic site and showed π‐π interaction with Trp278. The tertiary amino group displayed significant cation‐π interaction with Phe329. The aromatic group showed π‐π interaction with Trp83 at the catalytic anionic site. The long chain of methylene lay along the gorge interacting with Phe330 via hydrophobic interaction. Molecular docking was applied to postulate the selectivity toward AChE of 5a in comparison with donepezil and tacrine. Structural insights into the selectivity of the coumarin derivatives toward huAChE were explored by molecular docking and 3D QSAR and molecular dynamics simulation for 20 ns. ADMET analysis suggested that the 2‐(2‐oxo‐2H‐chromen‐4‐yl)acetamides showed a good pharmacokinetic profile and no hepatotoxicity. These coumarin derivatives showed high potential for further development as anti‐Alzheimer agents.     

Design,Synthesis, and Antitumor Activity of (E,Z)‐1‐(dihydrobenzofuran‐5‐yl)‐3‐phenyl‐2‐(1,2,4‐triazol‐1‐yl)‐2‐propen‐1‐ones

A series of (E,Z)‐1‐(dihydrobenzofuran‐5‐yl)‐3‐phenyl‐2‐(1,2,4‐triazol‐1‐yl)‐2‐propen‐1‐ones ( C1 – C35 ) were designed and synthesized, and the structures of compounds (Z)‐ C27 and (Z)‐ C29 were confirmed by single‐crystal X‐ray diffraction. The antitumor activities of these novel compounds against cervical cancer (HeLa), lung cancer (A549), and breast cancer (MCF‐7) cell lines were evaluated in vitro. Majority of the title compounds exhibited strong antitumor activities and were much more promising than the positive control Taxol, which were also accompanied by lower cytotoxicity to normal cells. In particular, compounds (E,Z)‐ C24 exhibited the most consistent potent activities against three neoplastic cells with IC₅₀ values ranging from 3.2 to 7.1 μm . Further researches demonstrated that compounds (E,Z)‐ C24 could induce cell apoptosis and arrest cell cycle at the G2/M and S phases. Meanwhile, the structure–activity relationship between the configurations and cytotoxicity of the compounds was also investigated.     

The synthesis of three isotopomers of 2‐methyl‐2‐(4‐[3‐[1‐(4‐methylbenzyl)‐5‐oxo‐4,5‐dihydro‐1H‐[1,2,4]triazol‐3‐yl]propyl]phenoxy)propionic acid,a potent and selective peroxisome proliferator‐activated receptor alpha agonist

Although fenofibrate ( 1a ) is commercially available and clinically effective in lowering serum triglycerides, its activity and sub‐type selectivity at the PPARα receptors are only moderate; therefore, there exists a need for more potent and sub‐type selective PPARα agonists. To that end, discovery efforts have identified 2‐methyl‐2‐(4‐[3‐[1‐(4‐methylbenzyl)‐5‐oxo‐4,5‐dihydro‐1H‐[1,2,4]triazol‐3‐yl]propyl]phenoxy)propionic acid ( 2 ), a potent and selective human PPARα receptor agonist. In support of pre‐clinical ADME studies and bioanalysis, three isotopomers of 2 have been synthesized. The results of these efforts are described below. Copyright © 2007 John Wiley & Sons, Ltd.     

Synthesis and biological evaluation of novel N‐aryl‐ω‐(benzoazol‐2‐yl)‐sulfanylalkanamides as dual inhibitors of α‐glucosidase and protein tyrosine phosphatase 1B

α‐Glucosidase is known to catalyze the digestion of carbohydrates and release free glucose into the digestive tract. Protein tyrosine phosphatase 1B (PTP1B) is engaged in the dephosphorylation of the insulin receptor and regulation of insulin sensitivity. Therefore, dual antagonists by targeting both α‐glucosidase and PTP1B may be potential candidates for type 2 diabetes therapy. In this work, three series of novel N‐aryl‐ω‐(benzoazol‐2‐yl)‐sulfanylalkanamides were synthesized and assayed for their α‐glucosidase and PTP1B inhibitory activities, respectively. Compound 3l , exhibiting the most effective α‐glucosidase inhibitory activity (IC₅₀ = 10.96 μm ( 3l ), IC₅₀ = 51.32 μm (Acarbose), IC₅₀ = 18.22 μm (Ursolic acid)) and potent PTP1B inhibitory activity (IC₅₀ = 13.46 μm ( 3l ), IC₅₀ = 14.50 μm (Ursolic acid)), was identified as a novel dual inhibitor of α‐glucosidase and PTP1B. Furthermore, 3l is a highly selective PTP1B inhibitor because no inhibition was showed by 3l at 100 μm against PTP‐MEG2, TCPTP, SHP2, or SHP1. Subsequent kinetic analysis revealed 3l inhibited α‐glucosidase in a reversible and mixed manner. Molecular docking study indicated that hydrogen bonds, van der Waals, charge interactions and Pi‐cation interactions all contributed to affinity between 3l and α‐glucosidase/PTP1B.     

Design,synthesis, and biological evaluation of 5‐(4‐(pyridin‐4‐yl)‐1H‐1,2,3‐triazol‐1‐yl)benzonitrile derivatives as xanthine oxidase inhibitors

A series of 5‐(4‐(pyridin‐4‐yl)‐1H‐1,2,3‐triazol‐1‐yl)benzonitrile derivatives ( 1a–p ) was designed, synthesized, and identified as xanthine oxidase inhibitors with micromolar level potencies. Among them, the most promising compounds 1j and 1k were obtained with IC₅₀ values of 8.1 and 6.7 μm , respectively. The Lineweaver–Burk plot revealed that compound 1k acted as a mixed‐type xanthine oxidase inhibitor. SAR analysis revealed that a carbon atom occupying the X³ position is not as effective as a nitrogen atom, and an iso‐pentyloxy or a cyclopentyloxy at the 2‐position of benzonitrile moiety will benefit the inhibitory potency. The basis of xanthine oxidase inhibition by 1k was rationalized by molecular modeling studies.     

Synthesis,in vitro evaluation and molecular docking studies of novel coumarin‐isatin derivatives as α‐glucosidase inhibitors

This study synthesized a series of novel coumarin‐isatin derivatives and evaluated them for α‐glucosidase inhibitory activity. The majority of the screened compounds exhibited excellent inhibition activities with IC₅₀ values of 2.56 ± 0.08–268.79 ± 3.04 μm , when compared to acarbose. Among the newly derivatives, compound 5p was found to be the most active compound in the library of coumarin‐isatin derivatives. Furthermore, enzyme kinetic studies showed that compound 5p is a non‐competitive inhibitor with a K_i of 2.14 μm . Molecular docking analysis revealed the existence of hydrophobic and hydrogen interactions between compound 5p and the active site of α‐glucosidase. Our results indicate that coumarin‐isatin derivatives as a new class of α‐glucosidase inhibitors.     

Carbon‐14‐and carbon‐13‐labeled phosphoric acid [2‐4‐(4‐cyanophenyl)‐thiazol‐2‐yl]‐(2,4‐difluorophenyl)‐1‐[1,2,4]triazol‐4‐yl‐methylpropoxymethyl] monoester dilysine salt,a prodrug of ravuconazole

4‐Bromobenzoic acid [carboxyl‐¹⁴C] and 4‐(2‐bromoacetyl) [Ar‐¹³C₆]benzonitrile were transformed into the title compounds containing [ring¹⁴C‐thiazol‐4‐yl] and [Ar‐¹³C₆‐benzonitrile]. ¹⁴C‐Ravuconazole was prepared in 37% yield and Purity >99%. ¹³C₆‐Ravuconazole was made in 56% overall yield and Purity of >98%. Each labeled compound was converted by additional reaction steps to the corresponding labeled prodrug. Copyright © 2011 John Wiley & Sons, Ltd     

Synthesis and mode of action studies of novel {2‐(3‐R‐1H‐1,2,4‐triazol‐5‐yl)phenyl}amines to combat pathogenic fungi

Due to their high specificity and efficacy, triazoles have become versatile antifungals to treat fungal infections in human healthcare and to control phytopathogenic fungi in agriculture. However, azole resistance is an emerging problem affecting human health as well as food security. Here we describe the synthesis of 10 novel {2‐(3‐R‐1H‐1,2,4‐triazol‐5‐yl)phenyl}amines. Their structure was ascertained by liquid chromatography–mass spectrometry, ¹H and ¹³C NMR, and elemental analysis data. Applying an in vitro growth assay, these triazoles show moderate to significant antifungal activity against the opportunistic pathogen Aspergillus niger, 12 fungi (Fusarium oxysporum, Fusarium fujikuroi, Colletotrichum higginsianum, Gaeumannomyces graminis, Colletotrichum coccodes, Claviceps purpurea, Alternaria alternata, Mucor indicus, Fusarium graminearum, Verticillium lecanii, Botrytis cinerea, Penicillium digitatum) and three oomycetes (Phytophtora infestans GL‐1, P. infestans 4/91; R+ and 4/91; R?) in the concentration range from 1 to 50 µg/ml (0.003–2.1 μM). Frontier molecular orbital energies were determined to predict their genotoxic potential. Molecular docking calculations taking into account six common fungal enzymes point to 14α‐demethylase (CYP51) and N‐myristoyltransferase as the most probable fungal targets. With respect to effectiveness, structure–activity calculations revealed the strong enhancing impact of adamantyl residues. The shown nonmutagenicity in the Salmonella reverse‐mutagenicity assay and no violations of drug‐likeness parameters suggest the good bioavailability and attractive ecotoxicological profile of the studied triazoles.     

Radiosynthesis of the α4β2 nicotinic acetylcholine receptor ligand: 5‐((1‐[11C]‐methyl‐2‐(S)‐pyrrolidinyl)methoxy)‐2‐chloro‐3‐((E)‐2‐(2‐fluoropyridin‐4‐yl)vinyl)pyridine

5‐((1‐[¹¹C]‐methyl‐2‐(S)‐pyrrolidinyl)methoxy)‐2‐chloro‐3‐((E)‐2‐(2‐fluoropyridin‐4‐yl)‐vinyl)pyridine ([¹¹C]‐FPVC) was synthesized from [¹¹C]‐methyl iodide and the corresponding normethyl precursor. The average time of synthesis, purification, and formulation was 42 min with an average non‐decay‐corrected radiochemical yield of 19%. The average specific radioactivity was 359 GBq/µmol (9691 mCi/µmole) at end of synthesis (EOS). Copyright © 2006 John Wiley & Sons, Ltd.     

Synthesis and Positive Inotropic Evaluation of (E)‐2‐(4‐Cinnamylpiperazin‐1‐yl)‐N‐(1‐substituted‐4,5‐dihydro‐[1,2,4]triazolo[4,3‐a]quinolin‐7‐yl)acetamides

A series of (E)‐2‐(4‐cinnamylpiperazin‐1‐yl)‐N‐(1‐substituted‐4,5‐dihydro‐[1,2,4]triazolo[4,3‐a]quinolin‐7‐yl)acetamides were synthesized and evaluated for their positive inotropic activity by measuring the left atrium stroke volume on isolated rabbit heart preparations. This class of compounds presented favorable in vitro activity compared with the standard drug, milrinone, among which N‐(1‐(3‐chlorophenyl)‐4,5‐dihydro‐[1,2,4]triazolo[4,3‐a]quinolin‐7‐yl)‐2‐(4‐cinnamylpiperazin‐1‐yl)acetamide 5e was found to be the most potent with 16.58 ± 0.11% increased stroke volume (milrinone: 2.46 ± 0.07%) at a concentration of 3 × 10^?5 M. The chronotropic effects of the compounds having inotropic effects were also evaluated.     

Synthesis and Evaluation of 3‐(furo[2,3‐b]pyridin‐3‐yl)‐4‐(1H‐indol‐3‐yl)‐maleimides as Novel GSK‐3β Inhibitors and Anti‐Ischemic Agents

A series of novel 3‐(furo[2,3‐b]pyridin‐3‐yl)‐4‐(1H‐indol‐3‐yl)‐maleimides were designed, synthesized, and biologically evaluated for their GSK‐3β inhibitory activities. Most compounds showed favorable inhibitory activities against GSK‐3β protein. Among them, compounds 5n , 5o , and 5p significantly reduced GSK‐3β substrate tau phosphorylation at Ser396 in primary neurons, indicating inhibition of cellular GSK‐3β activity. In the in vitro neuronal injury models, compounds 5n , 5o , and 5p prevented neuronal death against glutamate, oxygen–glucose deprivation, and nutrient serum deprivation which are closely associated with cerebral ischemic stroke. In the in vivo cerebral ischemia animal model, compound 5o reduced infarct size by 10% and improved the neurological deficit. The results may provide new insights into the development of novel GSK‐3β inhibitors with potential neuroprotective activity against brain ischemic stroke.     

Synthesis,crystal structure and molecular conformation of Nα‐Boc‐l‐leucyl‐(Z)‐β‐(3‐pyridyl)‐α,β‐ dehydroalanyl‐l‐leucine methyl ester*

Abstract: A protected tridehydropeptide containing (Z)‐β‐(3‐pyridyl)‐α,β‐dehydroalanine (Δ^Z3Pal) residue, Boc‐Leu‐Δ^Z3Pal‐Leu‐OMe ( 1 ), was synthesized via Erlenmeyer azlactone method. X‐ray crystallographic analysis revealed that the peptide 1 adopts an extended conformation, which is similar to that of a Δ^ZPhe analog, Boc‐Leu‐Δ^ZPhe‐Leu‐OMe ( 2 ).     

Synthesis of [13C2, 15N]‐1,3‐2H‐1‐benzyl‐(Z)‐3‐(benzylidene)indolin‐2‐one

Parkinson disease (PD) is a neurodegenerative disorder characterized by the accumulation of α‐synuclein into Lewy bodies. 3‐Benzylidine‐indolin‐2‐one represents a class of compounds, which are known to inhibit the accumulation of α‐synuclein. In this paper, we report the synthesis of [¹³C] and [¹⁵N] labelled 1‐benzyl‐(Z)‐3‐(benzylidene)indolin‐2‐one from commercially available [¹³C₂]‐chloroacetic acid and [¹⁵N]‐aniline in five steps. The product will be used to study its metabolites in human liver microsomes by liquid chromatography‐tandem mass spectrometry.     

Synthesis of (R)‐ and (S)‐[O‐methyl‐11C]N‐[2‐[3‐(2‐cyano‐phenoxy)‐2‐hydroxy‐propylamino]‐ethyl]‐N′‐(4‐methoxy‐phenyl)‐urea as candidate high affinity β1‐adrenoceptor PET radioligands

Molecular imaging and quantification of myocardial β₁‐adrenoceptor (AR) rather than total β‐AR density is of great clinical interest since cardiac biopsy studies suggest that myocardial β₁‐AR density is reduced in patients with chronic heart failure whereas cardiac β₂‐AR density may vary. Positron emission tomography (PET), with appropriate radioligands, offers the possibility to assess β‐AR density non‐invasively in humans. However, no PET radioligand for the selective imaging of cardiac β₁‐ARs is clinically available. Here some derivatives of the well characterized β₁‐AR selective antagonist, ICI 89,406, namely the enantiomers of N‐[2‐[3‐(2‐cyano‐phenoxy)‐2‐hydroxy‐propylamino]‐ethyl]‐N′‐(4‐hydroxy‐phenyl)‐urea ( 5a and 5b ) were synthesized and evaluated in vitro. The (R)‐isomer 5a was more β₁‐selective but has lower affinity than its (S)‐enantiomer 5b (β₁‐AR selectivity: 6100 vs 1240; β₁‐affinity: K₁ = 0.288 nM vs K₁ = 0.067 nM). Etherification of the analogous desmethyl precursors, 5e and 5f , respectively, with [¹¹C]iodomethane gave ¹¹C‐labelled versions of 5a and 5b , namely 5g and 5h , in 44 ± 5% radiochemical yield (decay‐corrected) and 97.4 ± 1.3% radiochemical purity with specific radioactivities of 26.4 ± 9.4 GBq/µmol within 41.2 ± 3.4 min from the end of bombardment (n = 14). 5g and 5h are now being evaluated as candidate radioligands for myocardial β₁‐ARs. Copyright © 2005 John Wiley & Sons, Ltd.     

From β‐N‐tert‐butyloxycarbonyl N‐carboxyanhydrides to β‐aminoacid derivatives

Abstract: β‐N‐tert‐butyloxycarbonyl‐N‐carboxyanhydrides are very reactive β‐amino acid derivatives. They react cleanly and smoothly with different nucleophiles like aminoesters, enolates, N‐methyl‐d ‐glucamine, amidoximes to afford in good to excellent yields peptides, β‐amino ketocompounds, β‐aminosugars and functionalized disubstituted 1,2,4‐oxadiazoles.     

Potential effect of new (E)‐4‐hydroxy ‐N’‐(1‐(7‐hydroxy‐2‐oxo‐2H‐chromen‐3‐yl) ethylidene) benzohydrazide against acute myocardial infarction: Haemodynamic,biochemical and histological studies

This study aimed to explore the cardioprotective effect of new synthesized coumarin (E)‐4‐hydroxy‐N’‐(1‐(7‐hydroxy‐2‐oxo‐2H‐chromen‐3‐yl) ethylidene) benzohydrazide denoted (Hyd.Cou) against myocardial infarction disorders. Male Wistar rats were divided into four groups; Control, isoproterenol (ISO), ISO + Acenocoumarol (Ac) and ISO + Hyd.Cou. Results showed that the ISO group exhibited serious alteration in EGC pattern, significant heart hypertrophy (+33%), haemodynamic disturbance and increase in plasma rate of CK‐MB, LDH and troponin‐T by 44, 53, and 170%, respectively, as compared to Control. Moreover, isoproterenol induced a rise in plasma angiotensin‐converting enzyme activity (ACE) by 49%, dyslipidaemia, and increased thiobarbituric acid‐reactive substances (TBARS) by 117% associated with decrease in the activity of superoxide dismutase (SOD) and glutathione peroxidase (GPx) by 46% and 58%, respectively in myocardium. Interestingly, the molecular docking calculation demonstrated strong interactions of Hyd.Cou with the receptors of the protein disulphide isomerase (PDI) which could highlight the antithrombotic effect. Moreover, Hyd.Cou improved plasma cardiac dysfunction biomarkers, mitigated the ventricle remodelling process and alleviated heart oxidative stress damage. Overall, Hyd.Cou prevented the heart from the remodelling process through inhibition of ACE activity and oxidative stress improvement.     

(Z)‐2‐(3‐Chlorobenzylidene)‐3,4‐dihydro‐N‐(2‐methoxyethyl)‐3‐oxo‐2H‐benzo[b][1,4]oxazine‐6‐carboxamide as GSK‐3β inhibitor: Identification by virtual screening and its validation in enzyme‐ and cell‐based assay

Glycogen synthase kinase 3β (GSK‐3β) is a widely investigated molecular target for numerous diseases including Alzheimer's disease, cancer, and diabetes mellitus. The present study was aimed to discover new scaffolds for GSK‐3β inhibition, through protein structure‐guided virtual screening approach. With the availability of large number of GSK‐3β crystal structures with varying degree of RMSD in protein backbone and RMSF in side chain geometry, herein appropriate crystal structures were selected based on the characteristic ROC curve and percentage enrichment of actives. The validated docking protocol was employed to screen a library of 50,000 small molecules using molecular docking and binding affinity calculations. Based on the GLIDE docking score, Prime MMGB/SA binding affinity, and interaction pattern analysis, the top 50 ligands were selected for GSK‐3β inhibition. (Z)‐2‐(3‐chlorobenzylidene)‐3,4‐dihydro‐N‐(2‐methoxyethyl)‐3‐oxo‐2H‐benzo[b][1,4]oxazine‐6‐carboxamide (F389‐0663, 7 ) was identified as a potent inhibitor of GSK‐3β with an IC₅₀ value of 1.6 μm . Further, GSK‐3β inhibition activity was then investigated in cell‐based assay. The treatment of neuroblastoma N2a cells with 12.5 μm of F389‐0663 resulted in the significant increase in GSK‐3β Ser9 levels, which is indicative of the GSK‐3β inhibitory activity of a compound. The molecular dynamic simulations were carried out to understand the interactions of F389‐0663 with GSK‐3β protein.