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International audience; Pyrimidine-fused compounds are of great interest for the discovery of potent bioactive agents. This study describes the synthesis of novel pyranopyrimidines 3a-f and pyranotriazolopyrimidines 4a-d derivatives via the cyclocondensation reaction of α-functionalized iminoether 2, which was obtained from 2-amino-3-cyanopyrane 1, with a series of primary aromatic amines and hydrazides, respectively. Structures of all synthesized compounds were established on the basis of spectroscopic methods including 1H NMR, 13C NMR and ES-HRMS. They were finally tested for their anticoagulant and anti-tyrosinase activities. Significant results have been obtained and the structure-activity relationship (SAR) was discussed with the help of molecular docking analysis. © 2018

Lead‐optimization strategies for compounds targeting c‐Myc G‐quadruplex (G4) DNA are being pursued to develop anticancer drugs. Here, we investigate the structure‐activity‐ relationship (SAR) of a newly synthesized series of molecules based on the pyrrolidine‐substituted 5‐nitro indole scaffold to target G4 DNA. Our synthesized series allows modulation of flexible elements with a structurally preserved scaffold. Biological and biophysical analyses illustrate that substituted 5‐nitroindole scaffolds bind to the c‐Myc promoter G‐quadruplex. These compounds downregulate c‐Myc expression and induce cell‐cycle arrest in the sub‐G1/G1 phase in cancer cells. They further increase the concentration of intracellular reactive oxygen species. NMR spectra show that three of the newly synthesized compounds interact with the terminal G‐quartets (5′‐ and 3′‐ends) in a 2 : 1 stoichiometry., Targeting DNA‐G‐quadruplexes: Fragment extension of indole fragments resulted in the synthesis of a series of pyrrolidine‐substituted 5‐nitroindole derivatives that bind to the c‐Myc G‐quadruplex DNA in a 2 : 1 stoichiometry. We could show that the compounds downregulate c‐Myc expression and induce cell‐cycle arrest in cancer cells.

Previously phytochemical investigations carried out on the flowers and trunk bark extracts of Citharexylum spinosum L. tree, allowed the isolation of twenty molecules belonging to several families of natural substances [triterpene acids, iridoid glycosides, phenylethanoid glycosides, 8,3'-neolignan glycosides, together with other phenolic compounds]. In the present work, a biological evaluation (anti-tyrosinase, anticholinesterase and cytotoxic activities) was performed on the prepared extracts and the isolated secondary metabolites. The results showed that the EtOAc extract of the trunk bark displayed the highest anti-tyrosinase effect with a percent inhibition of 55.0 +/- 1.8% at a concentration of 100 mu g/mL. The highest anticholinesterase activity was presented by the same extract with an IC50 value of 99.97 +/- 3.01 mu g/mL. The EtOAc extract of flowers and that of the trunk bark displayed the best cytotoxic property with IC50 values of 96.00 +/- 2.85 and 88.75 +/- 2.00 mu g/mL, respectively, against the human cervical cancer cell line (HeLa), and IC50 values of 188.23 +/- 3.88 and 197.00 +/- 4.25 mu g/mL, respectively, against the human lung cancer (A549) cell lines. Biological investigation of the pure compounds showed that the two 8,3'-neolignan glycosides, plucheosides D-1-D-2, generate the highest anti-tyrosinase potency with a percent inhibition of 61.4 +/- 2.0 and 79.5 +/- 2.3%, respectively, at a concentration of 100 mu M. The iridoid glycosides exhibited a significant anticholinesterase activity with IC50 values ranging from 17.19 +/- 1.02 to 52.24 +/- 2.50 mu M. Triterpene pentacyclic acids and iridoid glycosides exerted encouraging cytotoxic effects against HeLa with IC50 values ranging from 9.00 +/- 1.10 to 25.00 +/- 1.00 mu M. The study of the structure-activity relationship (SAR) has been sufficiently and widely discussed. The natural compounds that exhibited the significant bioactivities were docked.

The respiratory chain of Escherichia coli contains two different types of terminal oxidase that are differentially regulated as a response to changing environmental conditions. These oxidoreductases catalyze the reduction of molecular oxygen to water and contribute to the proton motive force. The cytochrome bo 3 oxidase (cyt bo 3) acts as the primary terminal oxidase under atmospheric oxygen levels, whereas the bd‐type oxidase is most abundant under microaerobic conditions. In E. coli, both types of respiratory terminal oxidase (HCO and bd‐type) use ubiquinol‐8 as electron donor. Here, we assess the inhibitory potential of newly designed and synthesized 3‐alkylated Lawson derivatives through L‐proline‐catalyzed three‐component reductive alkylation (TCRA). The inhibitory effects of these Lawson derivatives on the terminal oxidases of E. coli (cyt bo 3 and cyt bd‐I) were tested potentiometrically. Four compounds were able to reduce the oxidoreductase activity of cyt bo 3 by more than 50 % without affecting the cyt bd‐I activity. Moreover, two inhibitors for both cyt bo 3 and cyt bd‐I oxidase could be identified. Based on molecular‐docking simulations, we propose binding modes of the new Lawson inhibitors. The molecular fragment benzyl enhances the inhibitory potential and selectivity for cyt bo 3, whereas heterocycles reduce this effect. This work extends the library of 3‐alkylated Lawson derivatives as selective inhibitors for respiratory oxidases and provides molecular probes for detailed investigations of the mechanisms of respiratory‐chain enzymes of E. coli., To b or not to b: Alkylated hydroxynaphthoquinone derivatives, synthesized by reductive alkylation and tested for their inhibitory effect on bacterial respiratory oxidases, showed selectivity for one particular cytochrome b oxidase. Enzyme activity assays and docking analysis provided insights into their binding site. Alkylation with cyclic residues like benzyl groups only increased the inhibitory effect of one oxidase.

International audience; 2-substitued-benzopyrimidinones 2 were synthesized in high to excellent yields in a single step via condensation of 2-aminobenzamide 1 with some aryl-aldehydes in the presence of iodine. Cyclocondensation reaction of hydrazides 3 which were obtained in two steps from benzopyrimidinones 2, with some electrophilic species such as 2,4-pentandione, 2,5-hexandione, 1-phenylbutan-1,3-dione and cyclic anyhdrides provided the new compounds 4a–c, 5a–c, 6a–c, 7a–c, 8a–c and 9a–c. The synthesized compounds were characterized by spectroscopic means. They were also evaluated for their anti-tyrosinase potential. The structure-activity relationship (SAR) was discussed on the basis of the molecular docking analysis. © 2019

International audience; Isoindolinones and tricyclic N,O‐acetals are obtained from bis‐N‐acyliminium precursors and assorted nucleophiles using catalytic Bi(OTf)3. The reactions proceed, respectively, through a double amidoalkylation or tandem π‐cyclisation/α‐oxa‐amidoalkylation. Mechanistic aspects of the tandem chemistry are supported by DFT calculations and its utility in RCM and Click reactions illustrated.New 1,3‐bis‐N‐acyliminium species generated easily with nontoxic Bi(OTf)3 catalyst at very low loadings (2 mol‐%) were trapped inter‐ and intramolecularly with various poly‐nucleophiles. This mild, efficient, practical and general tandem approach provides an array of substituted isoindolinones and cyclic N,O‐acetals.

A short and effective approach to the synthesis of the topoisomerase I inhibitor isoindolo[2,1-b]isoquinolin-7(5H)-one and the alkaloid rosettacin belonging to the aromathecin family is presented. The key step of this sequence, which resulted in the formation of a five-membered ring, was the aryl radical cyclization of enamides generated using N-acyliminium chemistry.

A series of imidazo[2,1-b][1,3,4]thiadiazole-linked oxindoles composed of an A, B, C and D ring system were synthesized and investigated for anti-proliferative activity in various human cancer cell lines; test compounds were variously substituted at rings C and D. Among them, compounds 7 ((E)-5-fluoro-3-((6-p-tolyl-2-(3,4,5-trimethoxyphenyl)-imidazo[2,1-b][1,3,4]thiadiazol-5-yl)methylene)indolin-2-one), 11 ((E)-3-((6-p-tolyl-2-(3,4,5-trimethoxyphenyl)imidazo[2,1-b][1,3,4]thiadiazol-5-yl)methylene)indolin-2-one), and 15 ((E)-6-chloro-3-((6-phenyl-2-(3,4,5-trimethoxyphenyl)imidazo[2,1-b][1,3,4]thiadiazol-5-yl)methylene)indolin-2-one) exhibited potent anti-proliferative activity. Treatment with these three compounds resulted in accumulation of cells in G2 /M phase, inhibition of tubulin assembly, and increased cyclin-B1 protein levels. Compound 7 displayed potent cytotoxicity, with an IC50 range of 1.1-1.6 μM, and inhibited tubulin polymerization with an IC50 value (0.15 μM) lower than that of combretastatin A-4 (1.16 μM). Docking studies reveal that compounds 7 and 11 bind with αAsn101, βThr179, and βCys241 in the colchicine binding site of tubulin.

A series of novel sEH inhibitors containing a N-substituted piperidine ring [N-urea (8a–i) (9a–l) and amide derivatives (6a–l) (7a–l)] with pyrazole (a five-membered polar heterocycle) as a pharmacophore lead for sEH inhibition have been designed, synthesized and evaluated as novel analogues to reduce blood pressure elevation and inflammatory roles by acting as sEH inhibitors. The synthesized compound shows varying degree of selectivity towards the sEH enzymes. Particularly compounds 9g and 8h emerged as the most potent sEH inhibitor displaying IC50 values of 0.224 ± 0.014 and 0.220 ± 0.03 μM for in vitro sEH inhibition. Molecular docking studies of the designed sEH dual inhibitors are performed using 1ZD5 for sEH as the targeted proteins and which revealed H-bond interactions similar to AUDA. Structure–activity relationships provided useful insights in these classes of compounds and paved the way to design novel analogues with increased potency. Schematic representation of proposed sEH Inhibitors.

A series of chalcone conjugates featuring the imidazo[2,1-b]thiazole scaffold was designed, synthesized, and evaluated for their cytotoxic activity against five human cancer cell lines (MCF-7, A549, HeLa, DU-145 and HT-29). These new hybrid molecules have shown promising cytotoxic activity with IC50 values ranging from 0.64 to 30.9 μM. Among them, (E)-3-(6-(4-fluorophenyl)-2,3-bis(4-methoxyphenyl)imidazo[2,1-b]thiazol-5-yl)-1-(pyridin-2-yl)prop-2-en-1-one (11 x) showed potent antiproliferative activity with IC50 values ranging from 0.64 to 1.44 μM in all tested cell lines. To investigate the mechanism of action, the detailed biological aspects of this promising conjugate (11 x) were carried out on the A549 lung cancer cell line. The tubulin polymerization assay and immunofluoresence analysis results suggest that this conjugate effectively inhibits microtubule assembly in A549 cells. Flow cytometric analysis revealed that this conjugate induces cell-cycle arrest in the G2/M phase and leads to apoptotic cell death. This was further confirmed by Hoechst staining, activation of caspase-3, DNA fragmentation analysis, and Annexin V-FITC assay. Moreover, molecular docking studies indicated that this conjugate (11 x) interacts and binds efficiently with the tubulin protein.

In an attempt to develop potent anticancer agents, a series of 2-anilinonicotinyl-linked acrylamide conjugates were designed, synthesized, and evaluated for cytotoxic activity against various human cancer cell lines, anti-tubulin activity and cell-cycle effects. Among the series, compounds 6 d [(E)-N-(6-fluorobenzo[d]thiazol-2-yl)-3-(2-((3,4,5-trimethoxyphenyl)amino)pyridin-3-yl)acrylamide] and 6 p [(E)-3-(2-((4-methoxyphenyl)amino)pyridin-3-yl)-N-(6-nitrobenzo[d]thiazol-2-yl)acrylamide] showed promising cytotoxicity, specifically against the A549 human lung adenocarcinoma epithelial cell line, with GI50 values of 0.6±0.23 and 1.8±0.22 μM, respectively. Furthermore, cell-cycle perturbation studies by flow cytometry analysis indicated drastic cell-cycle effects in the G2 /M phase in this cell line followed by caspase-3 activation and apoptotic cell death. Molecular docking studies of the most potent compound, 6 d, revealed that this compound interacts with and binds efficiently in the active site of tubulin.

A series of benzo[b]furans was synthesized with modification at the 5-position of the benzene ring by introducing C-linked substituents (aryl, alkenyl, alkynyl, etc.). These compounds were evaluated for their antiproliferative activities, inhibition of tubulin polymerization, and cell-cycle effects. Some compounds in this series displayed excellent activity in the nanomolar range against lung cancer (A549) and renal cell carcinoma (ACHN) cancer cell lines. (6-Methoxy-5-((4-methoxyphenyl)ethynyl)-3-methylbenzofuran-2-yl)(3,4,5-trimethoxyphenyl)methanone (26) and (E)-3-(6-methoxy-3-methyl-2-(1-(3,4,5-trimethoxyphenyl)vinyl)benzofuran-5-yl)prop-2-en-1-ol (36) showed significant activity in the A549 cell line, with IC50 values of 0.08 and 0.06 mm, respectively. G2/M cell-cycle arrest and subsequent apoptosis was observed in the A549 cell line after treatment with these compounds. The most active compound in this series, 36, also inhibited tubulin polymerization with a value similar to that of combretastatin A-4 (1.95 and 1.86 mm, respectively). Furthermore, detailed biological studies such as Hoechst 33258 staining, DNA fragmentation and caspase-3 assays, and western blot analyses with the pro-apoptotic protein Bax and the anti-apoptotic protein Bcl-2 also suggested that these compounds induce cell death by apoptosis. Molecular docking studies indicated that compound 36 interacts and binds efficiently with the tubulin protein.