Synthesis and evaluation of novel E-2-(2-thienyl)- and Z-2-(3-thienyl)-3-arylacrylonitriles as antifungal and anticancer agents

Antitumor activity of the new tyrphostin briva against BRAFV600E-mutant colorectal carcinoma cells

Because of a reduced sensitivity of BRAF-mutant colorectal cancers to BRAF inhibitor treatment when compared with BRAF-mutant melanoma, it is essential to develop efficient drugs to cope with this disease. The new 2-(4-bromophenyl)-3-arylacrylonitrile compound Briva was prepared in one step from commercially available starting compounds. Briva and two known thiophene analogs (Thio-Iva and Thio-Dam) were tested for their cytotoxic activity against various tumor cell lines including colorectal and breast cancer cells. The antitumor activities of the test compounds were assessed in vitro via the MTT assay, DAPI staining of nuclei, RT-PCR and immunoblotting, wound healing, clonogenic assay, collagen I adhesion assay, and kinase inhibition assays. A selective activity of Briva was observed against BRAFV600E-mutant HT-29 and COLO-201 colorectal carcinoma (CRC) cells. Briva caused inhibition of HT-29 clonogenic tumor growth and was found to induce cytotoxicity by activating the intrinsic apoptosis pathway. In addition, Briva reduced HT-29 cell adhesion and migration. Kinase inhibition experiments revealed that Briva inhibits VEGFR2. Thus, Briva can be considered as a promising antitumor compound against BRAFV600E-mutant colon carcinoma by targeting VEGFR2 tyrosine kinase and consequently reducing cell adhesion and metastasis formation.

New NADPH Oxidase 2 Inhibitors Display Potent Activity against Oxidative Stress by Targeting p22phox-p47phox Interactions

NADPH oxidase (NOX2) is responsible for reactive oxygen species (ROS) production in neutrophils and has been recognized as a key mediator in inflammatory and cardiovascular pathologies. Nevertheless, there is a lack of specific NOX2 pharmacological inhibitors. In medicinal chemistry, heterocyclic compounds are essential scaffolds for drug design, and among them, indole is a very versatile pharmacophore. We tested the hypothesis that indole heteroaryl-acrylonitrile derivatives may serve as NOX2 inhibitors by evaluating the capacity of 19 of these molecules to inhibit NOX2-derived ROS production in human neutrophils (HL-60 cells). Of these compounds, C6 and C14 exhibited concentration-dependent inhibition of NOX2 (IC₅₀~1 µM). These molecules also reduced NOX2-derived oxidative stress in cardiomyocytes and prevented cardiac damage induced by ischemia-reperfusion. Compound C6 significantly reduced the membrane translocation of p47^phox, a cytosolic subunit that is required for NOX2 activation. Molecular docking analyses of the binding modes of these molecules with p47^phox indicated that C6 and C14 interact with specific residues in the inner part of the groove of p47^phox, the binding cavity for p22^phox. This combination of methods showed that novel indole heteroaryl acrylonitriles represent interesting lead compounds for developing specific and potent NOX2 inhibitors.

Novel Thienyl-Based Tyrosine Kinase Inhibitors for the Treatment of Hepatocellular Carcinoma

New medical treatments are urgently needed for advanced hepatocellular carcinoma (HCC). Recently, we showed the anticancer effects of novel thiophene-based kinase inhibitors. In this study, we further characterized the antineoplastic effects and modes of action of the two most promising inhibitors, Thio-Iva and Thio-Dam, and compared their effects with the clinically relevant multi-kinase inhibitor, sorafenib, in HCC cells. Crystal violet staining and real-time cell growth monitoring showed pronounced antiproliferative effects in Huh-7 and SNU-449 cells with IC50 values in the (sub-)micromolar range. Long-term incubation experiments revealed the reduced clonogenicity of Thio-Iva and Thio-Dam-treated HCC cells. LDH-release tests excluded cytotoxicity as an unspecific mode of action of the inhibitors, while flow cytometry analysis revealed a dose-dependent and pronounced G2/M phase cell cycle arrest and cyclin B1 suppression. Additionally, mitochondria-driven apoptosis was observed through the cytosolic increase of reactive oxygen species, a concomitant PARP cleavage, and caspase-3 induction. Both compounds were found to effectively inhibit the capillary tube formation of endothelial EA.hy926 cells in vitro, pointing towards additional antiangiogenic effects. Antiangiogenic and antineoplastic effects were confirmed in vivo by CAM assays. In summary, the thienyl-acrylonitrile derivatives, Thio-Iva and Thio-Dam, exert significant antineoplastic and antiangiogenic effects in HCC cells.

Insights into the chemistry and therapeutic potential of acrylonitrile derivatives

Acrylonitrile is a fascinating scaffold widely found in many natural products, drugs, and drug candidates with various biological activities. Several drug molecules such as entacapone, rilpivirine, teriflunomide, and so forth, bearing an acrylonitrile moiety have been marketed. In this review, diverse synthetic strategies for constructing desired acrylonitriles are discussed, and the different biological activities and medicinal significance of various acrylonitrile derivatives are critically evaluated. The information gathered is expected to provide rational guidance for the development of clinically useful agents from acrylonitriles.

New 3-Aryl-2-(2-thienyl)acrylonitriles with High Activity Against Hepatoma Cells

New 2-(thien-2-yl)-acrylonitriles with putative kinase inhibitory activity were prepared and tested for their antineoplastic efficacy in hepatoma models. Four out of the 14 derivatives were shown to inhibit hepatoma cell proliferation at (sub-)micromolar concentrations with IC50 values below that of the clinically relevant multikinase inhibitor sorafenib, which served as a reference. Colony formation assays as well as primary in vivo examinations of hepatoma tumors grown on the chorioallantoic membrane of fertilized chicken eggs (CAM assay) confirmed the excellent antineoplastic efficacy of the new derivatives. Their mode of action included an induction of apoptotic capsase-3 activity, while no contribution of unspecific cytotoxic effects was observed in LDH-release measurements. Kinase profiling of cancer relevant protein kinases identified the two 3-aryl-2-(thien-2-yl)acrylonitrile derivatives 1b and 1c as (multi-)kinase inhibitors with a preferential activity against the VEGFR-2 tyrosine kinase. Additional bioinformatic analysis of the VEGFR-2 binding modes by docking and molecular dynamics calculations supported the experimental findings and indicated that the hydroxy group of 1c might be crucial for its distinct inhibitory potency against VEGFR-2. Forthcoming studies will further unveil the underlying mode of action of the promising new derivatives as well as their suitability as an urgently needed novel approach in HCC treatment.

Sulfonic acid functionalized metal-organic framework (S-IRMOF-3): a novel catalyst for sustainable approach towards the synthesis of acrylonitriles

A sulfonic acid functionalized metal-organic framework (S-IRMOF-3) has been synthesized by dropwise addition of chlorosulfonic acid (0.5 mL) in IRMOF-3 (1 g) containing 20 mL of CHCl3 at 0 °C under simple stirring. The catalyst was applied in Knoevenagel condensation of various aromatic and hetero-aromatic aldehydes forming acrylonitrile derivatives. The catalyst was characterized thoroughly by using FT-IR, XRD, 13C MAS NMR, SEM, EDX, elemental mapping, TEM, BET, NH3-TPD and TGA/DTA techniques. The presence of characteristic bands at 1694 cm-1, 1254-769 cm-1 and 1033 cm-1 in the FT-IR spectrum, 2θ ≃ 6.7° and 9.8° in the XRD pattern and δ = 31.79, 39.55, 129.61, 131.46 (4C, CH), 133.54, 140.07 (2C), 167.71, 171.47 ppm (2C, 2C[double bond, length as m-dash]O) in the solid state 13C MAS NMR spectrum confirmed the successful formation of catalyst. This new eco-friendly approach resulted in a significant improvement in the synthetic efficiency (90-96% yield), high product purity, and minimizing the production of chemical wastes without using highly toxic reagents for the synthesis of acrylonitriles with selectivity for (Z)-isomer. Steric interactions seem to have an influence on the control of the Z-configurational isomers. By performing DFT calculations, it was found that the (Z)-isomer 3a is stabilized by 1.64 kcal mol-1 more than the (E)-isomer. The catalyst could be reused for five consecutive cycles without substantial loss in catalytic activity.

Synthesis of New (E)-2-(1H-Indole-3-ylcarbonyl)-3-heteroaryl-acrylonitriles via Microwave-Assisted Knoevenagel Condensation

Given the broad spectrum of biological uses of heteroaryl-acrylonitrile derivatives, it is necessary to find simple methods to synthesize and diversify this family of compounds. We report a stereoselective synthesis of a series of new (E)-2-(1H-indole-3-ylcarbonyl)-3-heteroaryl-acrylonitriles (3a–3i) obtained from 3-(cyanoacetyl)indole and heteroaryl-aldehydes under microwave-assisted Knoevenagel reaction at 300 W of potency and 100°C. The desired derivatives (3a–3i) were obtained with variable yields (30–94%) and time reactions (8–90 min). All the heteroaryl-acrylonitriles were characterized by physicoanalytical techniques such IR, 1H, 13C NMR, and electrospray mass spectrometry.

Crystal structure of (E)-2-(benzo[d]thiazol-2-yl)-3-(pyridin-3-yl)acrylonitrile)

C15H9N3S, triclinic, P1̅ (no. 2), a = 9.5737(5) Å, b = 12.0958(4) Å, c = 12.2705(7) Å, α = 64.083(5) Å, β = 80.907(4) Å, γ = 82.800(4), V = 1259.44(11) Å3, Z = 4, R gt (F) = 0.0460, wR ref (F 2 ) = 0.140, T = 293(2) K.

Ultrasound-assisted phase-transfer catalysis method in an aqueous medium to promote the Knoevenagel reaction: advantages over the conventional and microwave-assisted solvent-free/catalyst-free method

Given the broad spectrum of uses of acrylonitrile derivatives as fluorescent probes, AChE inhibitors, and others, it is necessary to find easy, efficient and simple methods to synthesize and diversify these compounds. We report the results of a comparative study of the effects of three techniques on the reactions between heterocyclic aldehydes and 2-(benzo[d]thiazol-2-yl)acetonitrile: stirring; ultrasound coupled to PTC conditions (US-PTC); and MW irradiation (MWI) under solvent and catalyst-free conditions. The effects of conditions on reaction parameters were evaluated and compared in terms of reaction time, yield, purity and outcomes. The US-PTC method is more efficient than the MWI and conventional methods. The reaction times were considerably shorter, with high yields (>90%) and good levels of purity. In addition, X-ray diffraction analysis and quantum mechanical calculations, at the level of density functional theory (DFT), ratify obtaining acrylonitrile isomers with E configurations. The crystal structure of 3c is stabilized by weak C-Ho⋯N intermolecular interactions (Ho⋯NC=2.45 Å, Co⋯NC=3.348(3) Å, Ho⋯NC=162°), forming centrosymmetric ring R2(2) (20) along the crystallographic a axis.

A novel class of selective acetylcholinesterase inhibitors: synthesis and evaluation of (E)-2-(benzo[d]thiazol-2-yl)-3-heteroarylacrylonitriles

(E)-2-(benzo[d]thiazol-2-yl)-3-heteroarylacrylonitriles are described as a new class of selective inhibitors of acetylcholinesterase (AChE). The most potent compound in the series exhibited good AChE inhibitory activity (IC₅₀ = 64 µM). Compound 7f was found to be more selective than galanthamine in inhibiting AChE and it showed a moderate selectivity index. Kinetic studies on AChE indicated that a competitive type of inhibition pattern exist for these acrylonitrile derivates. Molecular docking models of the ligand-AChE complexes suggest that compound 7 g is located on the periphery of the AChE active site.

Synthesis and antiproliferative activity of novel symmetrical alkylthio- and alkylseleno-imidocarbamates

The study described here concerns the synthesis of a series of thirty new symmetrically substituted imidothiocarbamate and imidoselenocarbamate derivatives and their evaluation for antitumoral activity in vitro against a panel of five human tumor cell lines: breast adenocarcinoma (MCF-7), colon carcinoma (HT-29), lymphocytic leukemia (K-562), hepatocarcinoma (Hep-G2), prostate cancer (PC-3) and one non-malignant mammary gland-derived cell line (MCF-10A). The GI(50) values for eighteen of the compounds were below 10 μM in at least one cell line. Two cancer cells (MCF-7 and HT-29) proved to be the most sensitive to five compounds (1b, 2b, 3b, 4b and 5b), with growth inhibition in the nanomolar range, and compounds 1b, 3b, 7b, 8b and 9b gave values of less than 1 μM. In addition, all of the aforementioned compounds exhibited lower GI(50) values than some of the standard chemotherapeutic drugs used as references. The results also reveal that the nature of the aliphatic chain (methyl is better than benzyl) at the selenium position and the nature of the heteroatom (Se better than S) have a marked influence on the antiproliferative activity of the compounds. These findings reinforce our earlier hypothesis concerning the determinant role of the selenomethyl group as a scaffold for the biological activity of this type of compound. Considering both the cytotoxic parameters and the selectivity index (which was compared in MCF-7 and MCF-10A cells), compounds 2b and 8b (with a selenomethyl moiety) displayed the best profiles, with GI(50) values ranging from 0.34 nM to 6.07 μM in the five cell lines tested. Therefore, compounds 2b and 8b were evaluated by flow cytometric analysis for their effects on cell cycle distribution and apoptosis in MCF-7 cells. 2b was the most active, with an apoptogenic effect similar to camptothecin, which was used as a positive control. Both of them provoked cell cycle arrest leading to the accumulation of cells in either G(2)/M and S phase. These two compounds can therefore be considered as the most promising candidates for the development of novel generations of antitumor agents.