Synthesis, characterization, and derivatization of some novel types of fluorinated mono- and bis-imidazolidineiminothiones with antitumor, antiviral, antibacterial, and antifungal activities

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.

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.

Design, Synthesis, Antimicrobial and Anti-biofilm Evaluation, and Molecular Docking of Newly Substituted Fluoroquinazolinones

BACKGROUND

Quinazolines and quinazolinones derivatives are well known for their important range of therapeutic activities.

OBJECTIVE

The study aims to carry out the synthesis of some derivatives of substituted fluoroquinazolinones based on structure-based design and evaluation of their antibacterial, antifungal, and anti-biofilm activities.

METHODS

Compounds were chemically synthesized by conventional methods. Structures were established on the basis of spectral and elemental analyses. The antimicrobial potential was tested against various microorganisms using the agar disc-diffusion method. MIC and MBC as well as anti-biofilm activity for the highly active compounds were assessed. Moreover, the computational studies were performed using Auto dock free software package (version 4.0) to explain the predicted mode of binding.

RESULTS

All derivatives (5-8), (10a-g), and (A-H) were biologically tested and showed significant antimicrobial activity comparable to the reference compounds. Compounds 10b, 10c, and 10d had a good MIC and MBC against Gram-positive bacteria, whereas 10b and 10d showed significant MIC and MBC against Gram-negative bacteria. However, compounds E and F exhibited good MIC and MBC against fungi. Compound 10c and 8 exhibited significant anti-biofilm activity towards S. aureus and M. luteus. Molecular docking study revealed a strong binding of these derivatives with their receptor-site and detected their predicted mode of binding.

CONCLUSION

The synthesized derivatives showed promising antibacterial, antifungal, and antibiofilm activities. Modeling study explained their binding mode and showed strong binding affinity with their receptor-site. The highly active compounds 5 and 10c could be subjected to future optimization and investigation to be effective antimicrobial agents.

Quinazolinone-Amino Acid Hybrids as Dual Inhibitors of EGFR Kinase and Tubulin Polymerization

Some fluoroquinazolinones (A–H) were designed, synthesized and biologically evaluated for their antitumor activity against the two cell lines, MCF-7 and MDA-MBA-231. New derivative G (IC₅₀ = 0.44 ± 0.01 µM) showed antitumor activity, better than that of the reference drug erlotinib (IC₅₀ = 1.14 ± 0.04 µM) against MCF-7. New derivative E (IC₅₀ = 0.43 ± 0.02 µM) showed higher activity than the reference drug erlotinib (IC₅₀ = 2.55 ± 0.19 µM) against MDA-MBA-231. Furthermore, the EGFR (epidermal growth factor receptor) and tubulin inhibition assays were carried out for the highest active derivatives to reveal the expected mechanism of action. They exhibited significant results compared to the reference drugs. Molecular docking simulations were performed on EGFR and tubulin binding sites to rationalize the experimental results and describe their binding modes. The results of the molecular modeling study were correlated with that of the antitumor screening.

Design, Synthesis, Cytotoxic Evaluation and Molecular Docking of New Fluoroquinazolinones as Potent Anticancer Agents with Dual EGFR Kinase and Tubulin Polymerization Inhibitory Effects

A series of new fluoroquinazolinone 6⁻8 and 10a⁻g derivatives was designed, prepared and screened for their in vitro cytotoxic activity against human cancer cell lines MCF-7 and MDA-MBA-231. Compounds 6 (IC₅₀ = 0.35 ± 0.01 µM), 10f (IC₅₀ = 0.71 ± 0.01 µM), 10d (IC₅₀ = 0.89 ± 0.02 µM) and 10a (IC₅₀ = 0.95 ± 0.01 µM) displayed broad spectrum anticancer activity better than the reference drug gefitinib (IC₅₀ = 0.97 ± 0.02 µM) against MCF-7. Compounds 10e (IC₅₀ = 0.28 ± 0.02 µM), 10d (IC₅₀ = 0.38 ± 0.01 µM), 7 (IC₅₀ = 0.94 ± 0.07 µM) and 10c (IC₅₀ = 1.09 ± 0.01 µM) showed better activity than the reference gefitinib (IC₅₀ = 1.30 ± 0.04 µM) against MDA-MBA-231. Moreover, EGFR and tubulin inhibition assays were performed for the highest active derivatives and showed remarkable results comparing to the reference drugs. In order to assess and explain their binding affinities, molecular docking simulation was studied against EGFR and tubulin binding sites. The results obtained from molecular docking study and those obtained from cytotoxic screening were correlated.

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 and evaluation of antitubercular activity of fluorinated 5-aryl-4-(hetero)aryl substituted pyrimidines

Various 5-(fluoroaryl)-4-(hetero)aryl substituted pyrimidines have been synthesized based on the Suzuki cross-coupling and nucleophilic aromatic substitution of hydrogen (SN(H)) reactions starting from commercially available 5-bromopyrimidine and their antitubercular activity against Mycobacterium tuberculosis H37Rv has been explored. The outcome of the study disclose that, some of the compounds have showed promising activity in micromolar concentration against Mycobacterium tuberculosis H37Rv, Mycobacterium avium, Mycobacterium terrae, and multidrug-resistant strains isolated from tuberculosis patients in Ural region (Russia). The data concerning the 'structure-activity' relationship for fluorinated compounds have been discussed.