Synthesis and characterization of new types of halogenated and alkylated imidazolidineiminothiones and a comparative study of their antitumor, antibacterial, and antifungal activities

Design, synthesis, and mechanistic insight of novel imidazolones as potential EGFR inhibitors and apoptosis inducers

As regards to the structural analysis and optimization of diverse potential EGFR inhibitors, two series of imidazolyl-2-cyanoprop-2-enimidothioates and ethyl imidazolylthiomethylacrylates were designed and constructed as potential EGFR suppressors. The cytotoxic effect of the prepared derivatives was assessed toward hepatic, breast, and prostate cancerous cells (Hep-G2, MCF-7, and PC-3). Three derivatives 3d, 3e, and 3f presented potent antiproliferative activity and selectivity against the examined tumor cells showing IC50 values at low micromolar levels. Hence, successive biological assays were applied to determine the probable mechanism of action of the new compounds. They exhibited significant EGFR suppression with an IC50 range of 0.137-0.507 µM. The most effective EGFR inhibitor 3f arrested the MCF-7 cell cycle at the S phase by inducing the apoptotic pathway that was confirmed via increasing the expression of Caspases 8, 9, and Bax, which are associated with Bcl-2 decline. Additionally, molecular docking displayed a distinctive interaction between 3f and EGFR binding pocket. Overall, this work introduces some novel imidazolyl-2-cyanoprop-2-enimidothioates and ethyl imidazolylthiomethylacrylates as potential cytotoxic and EGFR inhibitors that deserve further research in tumor therapy.

First X-ray Crystal Structure Characterization, Computational Studies, and Improved Synthetic Route to the Bioactive 5-Arylimino-1,3,4-thiadiazole Derivatives

N-arylcyanothioformamides are useful coupling components for building key chemical intermediates and biologically active molecules in an expedited and efficient manner. Similarly, substituted (Z)-2-oxo-N-phenylpropanehydrazonoyl chlorides have been utilized in numerous one-step heteroannulation reactions to assemble the structural core of several different types of heterocyclic compounds. Herein, we demonstrate the effectiveness of the reaction of N-arylcyanothioformamides with various substituted (Z)-2-oxo-N-phenylpropanehydrazonoyl chlorides to produce, stereoselectively and regioselectively, a range of 5-arylimino-1,3,4-thiadiazole derivatives decorated with a multitude of functional groups on both aromatic rings. The synthetic methodology features mild room-temperature conditions, large substrate scope, wide array of functional groups on both reactants, and good to high reaction yields. The products were isolated by gravity filtration in all cases and structures were confirmed by multinuclear NMR spectroscopy and high accuracy mass spectral analysis. Proof of molecular structure of the isolated 5-arylimino-1,3,4-thiadiazole regioisomer was obtained for the first time by single-crystal X-ray diffraction analysis. Crystal-structure determination was carried out on (Z)-1-(5-((3-fluorophenyl)imino)-4-(4-iodophenyl)-4,5-dihydro-1,3,4-thiadiazol-2-yl)ethan-1-one and (Z)-1-(4-phenyl-5-(p-tolylimino)-4,5-dihydro-1,3,4-thiadiazol-2-yl)ethan-1-one. Similarly, the tautomeric structures of the N-arylcyanothioformamides and (Z)-geometries of the 2-oxo-N-phenylpropanehydrazonoyl chloride coupling partners were proven by X-ray diffraction studies. As representative examples, crystal-structure determination was carried out on (4-ethoxyphenyl)carbamothioyl cyanide and (Z)-N-(2,3-difluorophenyl)-2-oxopropanehydrazonoyl chloride. Density functional theory calculations at the B3LYP-D4/def2-TZVP level were carried out to rationalize the observed experimental findings.

Highly bioactive novel aryl-, benzyl-, and piperazine-selenoureas: synthesis, structural characterization and in vitro biological evaluation

Selenoureas are widespread as useful elements for constructing important species and biologically active molecules. Finding an efficient and straightforward method to prepare this motif and biologically screen derivatives thereof is crucial. Herein, we demonstrate the effectiveness of using ethanol as a solvent in the preparation of various substituted aryl-, benzyl-, and piperazine-selenoureas from isoselenocyanates and amines. The synthetic method includes mild reaction conditions, large substrate scope, and good isolated yields. Biological evaluation of the prepared products on MDA-MB-231 and MCF-7 cancer cell lines revealed several remarkably active compounds (IC₅₀ < 10 μΜ) with the best one exhibiting IC₅₀ values of 1.8 μΜ and 1.2 μΜ observed against the challenging former triple-negative breast cancer cell line and the latter one, respectively. The chemical structures of all new compounds were fully characterized by multinuclear nuclear magnetic resonance (NMR) spectroscopy and high accuracy mass measurements.

Appraisal of novel azomethine-thioxoimidazolidinone conjugates as ecto-5'-nucleotidase inhibitors: synthesis and molecular docking studies

Purinergic signaling is regulated by a group of extracellular enzymes called ectonucleotidases. One of its members i.e., ecto-5′-nucleotidase (h-e5′NT) is involved in the final step of the enzymatic hydrolysis cascade that is the conversion of adenosine monophosphate (AMP) to adenosine and therefore, involves the regulation of adenosine level in extracellular space. The overexpression of h-e5′NT has been observed in various pathological conditions such as hypoxia, inflammation and cancers, and led to various complications. Hence, the identification of a potent as well as selective inhibitor of h-e5′NT is of greater importance in therapeutic treatment of various diseases. Azomethine-thioxoimidazolidinone derivatives were studied for their inhibition potential against e5′NT enzyme along with cytotoxic potential against cancer cell lines possessing overexpression of e5′NT enzyme. The derivative (E)-3-((4-((3-methoxybenzyl)oxy)benzylidene)amino)-2-thioxoimidazolidin-4-one (4g) displayed selective and significant inhibition towards h-e5′NT with an IC₅₀ value of 0.23 ± 0.08 μM. While two other derivatives i.e., (E)-3-(((5-bromothiophen-2-yl)methylene)amino)-2-thioxoimidazolidin-4-one (4b) and 2-thioxo-3-((3,4,5-trimethoxybenzylidene)amino)imidazolidin-4-one (4e), exhibited non-selective potent inhibitory behavior against both human and rat enzymes. Moreover, these derivatives (4b, 4e and 4g) were further investigated for their effect on the expression of h-e5′NT using quantitative real time polymerase chain reaction. Additionally, molecular docking and DFT studies were also performed to determine the putative binding mode of potent inhibitors within the enzyme active site. HOMO, LUMO, ΔE, and molecular electrostatic potential maps were computed by DFT and the charge transfer regions within the molecules were identified to find out the regions for electrophilic and nucleophilic attack.

Azomethine–thioxoimidazolidinone conjugates as ecto-5′-nucleotidase inhibitors.

Iodine-DMSO mediated conversion of N-arylcyanothioformamides to N-arylcyanoformamides and the unexpected formation of 2-cyanobenzothiazoles

Cyanoformamides are ubiquitous as useful components for assembling key intermediates and bioactive molecules. The development of an efficient and simple approach to this motif is a challenge. Herein, we demonstrate the effectiveness of the I₂-DMSO oxidative system in the preparation of N-arylcyanoformamides from N-arylcyanothioformamides. The synthetic method features mild conditions, broad substrate scope, and high reaction efficiency. Furthermore, this method provides an excellent entry to exclusively afford 2-cyanobenzothiazoles which are useful substrates to access new luciferin analogs. The structures of all new products were elucidated by multinuclear NMR spectroscopy and high accuracy mass spectral analysis. Crystal-structure determination by means of single-crystal X-ray diffraction was carried out on (4-bromophenyl)carbamoyl cyanide, 5,6-dimethoxybenzo[d]thiazole-2-carbonitrile, 5-(benzyloxy)benzo[d]oxazole-2-carbonitrile, 4,7-dimethoxybenzo[d]thiazole-2-carbonitrile, and (5-iodo-2,4-dimethoxyphenyl)carbamoyl cyanide, a key intermediate with mechanistic implications.

Conversion of N-arylcyanothioformamides to N-arylcyanoformamides and 2-cyanobenzothiazoles has been achieved with I₂-DMSO oxidative system.

EGFR/VEGFR-2 dual inhibitor and apoptotic inducer: Design, synthesis, anticancer activity and docking study of new 2-thioxoimidazolidin-4one derivatives

AIMS

EGFR and VEGFR-2 have emerged as promising targets for cancer management as they play a crucial role in tumor growth, angiogenesis and metastasis. A novel series of 2-thioxoimidazolidin-4-one derivatives were synthesized and evaluated as apoptotic inducers and EGFR/VEGFR-2 dual inhibitors.

MAIN METHODS

The cytotoxic activities of all synthesized compounds were tested against MCF-7, HepG2 and A549 cell lines. The molecular mechanism of the most promising cytotoxic compounds was investigated via a series of assays including in vitro EGFR and VEGFR-2 inhibitory activity in MCF-7 cell line. Additionally, levels of p53, Bax, Bcl-2, caspase 7, 9 as well as cell cycle analysis were assessed in MCF-7 cell line to gain better understanding of their apoptotic activity. Molecular docking study was carried out to predict binding pattern of these compounds with EGFR and VEGFR-2 active sites. Finally, in silico ADME and drug-likeness profiling were calculated.

KEY FINDINGS

Compounds 6 and 8a exhibited superior cytotoxic activity compared to sorafenib and erlotinib, against the three tested cell lines. In the same context, 6 and 8a showed better EGFR and VEGFR-2 inhibitory activity compared to the reference compounds. The later effect was further supported by the docking study. Furthermore, these compounds displayed potent apoptotic activity as evident by cell accumulation at pre-G1 phase and cell cycle arrest at G2/M phase together with increased p53, caspae-7 and caspase-9 levels and Bax/Bcl-2 ratio. Finally, synthesized compounds have acceptable drug likeness.

SIGNIFICANCE

Compounds 6 and 8a act as potent dual EGFR/VEGFR-2 inhibitors with evident apoptotic activity.

Design, synthesis and evaluation of anticancer activity of novel 2-thioxoimidazolidin-4-one derivatives bearing pyrazole, triazole and benzoxazole moieties

A novel series of substituted 2-thiohydantoin incorporated with benzoimidazole, pyrazole, triazole and/or benzoxazole moieties has been synthesized using (E)-3-[1-(4-bromophenyl)ethylideneamino]-2-thioxoimidazolidin-4-one 1 as the key starting material. The key material 1 also, reacted with an acetic anhydride, aromatic aldehydes, secondary amines, formaldehyde and triethyl orthoformate to give the corresponding acetyl, chalcone, Mannich bases and ethoxymethylene derivatives, respectively. The structures of the novel compounds were confirmed by spectral data and elemental analysis. The cytotoxic activity of all synthesized compounds was assessed in vitro against human hepatocellular cancer cell line (HePG-2) and breast carcinoma cell line (MCF-7). The bioassay results revealed that compound 14 has the best activity against HePG-2 cell line (IC₅₀ = 2.33 μg/mL), while compound 5 has the best activity against MCF-7 cell line (IC₅₀ = 3.98 μg/mL).

Biotransformation of Bicyclic Halolactones with a Methyl Group in the Cyclohexane Ring into Hydroxylactones and Their Biological Activity

The aim of this study was the chemical synthesis of a series of halo- and unsaturated lactones, as well as their microbial transformation products. Finally some of their biological activities were assessed. Three bicyclic halolactones with a methyl group in the cyclohexane ring were obtained from the corresponding γ,δ-unsaturated ester during a two-step synthesis. These lactones were subjected to screening biotransformation using twenty two fungal strains. These strains were tested on their ability to transform halolactones into new hydroxylactones. Among the six strains able to catalyze hydrolytic dehalogenation, only two (Fusarium equiseti, AM22 and Yarrowia lipolytica, AM71) gave a product in a high yield. Moreover, one strain (Penicillium wermiculatum, AM30) introduced the hydroxy group on the cyclohexane ring without removing the halogen atom. The biological activity of five of the obtained lactones was tested. Some of these compounds exhibited growth inhibition against bacteria, yeasts and fungi and deterrent activity against peach-potato aphid.

Structure-activity relationship (SAR) study and design strategies of nitrogen-containing heterocyclic moieties for their anticancer activities

The present review article offers a detailed account of the design strategies employed for the synthesis of nitrogen-containing anticancer agents. The results of different studies describe the N-heterocyclic ring system is a core structure in many synthetic compounds exhibiting a broad range of biological activities. Benzimidazole, benzothiazole, indole, acridine, oxadiazole, imidazole, isoxazole, pyrazole, triazoles, quinolines and quinazolines including others drugs containing pyridazine, pyridine and pyrimidines are covered. The following studies of these compounds suggested that these compounds showed their antitumor activities through multiple mechanisms including inhibiting protein kinase (CDK, MK-2, PLK1, kinesin-like protein Eg5 and IKK), topoisomerase I and II, microtubule inhibition, and many others. Our concise representation exploits the design and anticancer potency of these compounds. The direct comparison of anticancer activities with the standard enables a systematic analysis of the structure-activity relationship among the series.

New 1,3-diaryl-5-thioxo-imidazolidin-2,4-dione derivatives: synthesis, reactions and evaluation of antibacterial and antifungal activities

New cyanothioformamide derivative 1 was prepared by treatment of 3,5-dichlorophenyl isothiocyanate with potassium cyanide at room temperature. Cycloaddition of cyanothioformamide 1 with phenyl isocyanate as electrophile furnished the corresponding imidazolidine 2. Imine hydrolysis of 2 with ethanolic HCl produced the corresponding 4-thioxo-2,5-imidazolidinedione 3. This compound was used as key synthon for the preparation of a wide variety of new substituted imidazole compounds. Condensation of 3 with different types of hydrazine derivatives furnished new series of hydrazone 4a, b, thiosemicarbazone 5a, b and cyanoacetohydrazide 6 derivatives incorporating imidazolidine moiety. Finally, cyanoacetohydrazide 6 was used as intermediate for synthesizing new compounds. Evaluation of the antibacterial and antifungal activities for the synthesized compounds was carried out to probe their activities. Most of the tested compounds showed significant activities. The dione derivative 3 and the imidazolidine derivative 9a, which incorporates a chromene moiety, exhibited high activity near the reference drug against all tested organisms.

Synthesis, biological evaluation and 2D-QSAR study of halophenyl bis-hydrazones as antimicrobial and antitubercular agents

In continuation of our endeavor towards the development of potent and effective antimicrobial agents, three series of halophenyl bis-hydrazones (14a-n, 16a-d, 17a and 17b) were synthesized and evaluated for their potential antibacterial, antifungal and antimycobacterial activities. These efforts led to the identification of five molecules 14c, 14g, 16b, 17a and 17b (MIC range from 0.12 to 7.81 μg/mL) with broad antimicrobial activity against Mycobacterium tuberculosis; Aspergillus fumigates; Gram positive bacteria, Staphylococcus aureus, Streptococcus pneumonia, and Bacillis subtilis; and Gram negative bacteria, Salmonella typhimurium, Klebsiella pneumonia, and Escherichia coli. Three of the most active compounds, 16b, 17a and 17b, were also devoid of apparent cytotoxicity to lung cancer cell line A549. Amphotericin B and ciprofloxacin were used as references for antifungal and antibacterial screening, while isoniazid and pyrazinamide were used as references for antimycobacterial activity. Furthermore, three Quantitative Structure Activity Relationship (QSAR) models were built to explore the structural requirements controlling the different activities of the prepared bis-hydrazones.