Fluorinated derivatives of 2-phenyl-3-hydroxy-4(1H)-quinolinone as tubulin polymerization inhibitors.

We have synthesized a series of 2-phenyl-3-hydroxy-4(1H)-quinolinone derivatives substituted with one or more fluorine atoms on the quinolone backbone as well as on phenyl ring. The derivatives bearing more fluorine atoms were subjected to modification by nucleophilic substitutions by thiophenol, morpholine, and piperazine derivative. We have tested the prepared compounds in cytotoxic activity assay against cancer cell lines. Four derivatives exhibited micromolar values of IC50 against some of the cancer cell lines, and we have subjected them to cell cycle analysis on CCRF-CEM. Moreover, most active 7-fluoro-3-hydroxy-2-phenyl-6-(phenylthio)quinolin-4(1H)-one inhibits mitosis progression. Cell cycle analysis, in vitro tubulin polymerization assay, and tubulin imaging in cells indicated that the anticancer activity of thiophenol derivative is associated with its ability to inhibit microtubule formation.

Identification of Eukaryotic Translation Elongation Factor 1-α 1 Gamendazole-Binding Site for Binding of 3-Hydroxy-4(1 H)-quinolinones as Novel Ligands with Anticancer Activity.

Here, we have identified the interaction site of the contraceptive drug gamendazole using computational modeling. The drug was previously described as a ligand for eukaryotic translation elongation factor 1-α 1 (eEF1A1) and found to be a potential target site for derivatives of 2-phenyl-3-hydroxy-4(1 H)-quinolinones (3-HQs), which exhibit anticancer activity. The interaction of this class of derivatives of 3-HQs with eEF1A1 inside cancer cells was confirmed via pull-down assay. We designed and synthesized a new family of 3-HQs and subsequently applied isothermal titration calorimetry to show that these compounds strongly bind to eEF1A1. Further, we found that some of these derivatives possess significant in vitro anticancer activity.

Synthesis of 4-substituted pyrazole-3,5-diamines via Suzuki-Miyaura coupling and iron-catalyzed reduction.

A general and efficient synthesis of 4-substituted-1H-pyrazole-3,5-diamines was developed to access derivatives with an aryl, heteroaryl, or styryl group, which are otherwise relatively difficult to prepare. The first step is based on the Suzuki-Miyaura cross-coupling reaction utilizing the XPhos Pd G2 precatalyst. The coupling reactions of 4-bromo-3,5-dinitro-1H-pyrazole with the electron-rich/deficient or sterically demanding boronic acids enabled the production of the corresponding dinitropyrazoles. The subsequent iron-catalyzed reduction of both nitro groups with hydrazine hydrate accomplished the synthesis. The additional demethylation of the 4-methoxystyryl derivative allowed the production of the carboanalog of CAN508 reported as a selective CDK9 inhibitor.

Inhibition of Na+/K+-ATPase by 5,6,7,8-tetrafluoro-3-hydroxy-2-phenylquinolin-4(1H)-one.

Na+/K+-ATPase (NKA) is an enzyme of crucial importance for all animal cells. We examined the inhibitory effects of halogenated phenylquinolinones on NKA. The 5,6,7,8-tetrafluoro-3-hydroxy-2-phenylquinolin-4(1H)-one (TFHPQ) was identified as an efficient NKA inhibitor with IC50 near 10 µM. The inhibition by TFHPQ is particularly efficient at higher concentrations of K+, where NKA adopts the E2 conformation. The experimental observations are in a good agreement with the outcomes from molecular docking. We identified an energetically favourable TFHPQ binding site for the K+-bound NKA, which is located in the proximity of the cytoplasmic C-terminus.

Solid-phase synthesis of 3-hydroxy-6-nitroquinolin-4(1H)-ones with two diversity positions.

The efficient solid-phase synthesis of 3-hydroxy-2,7-disubstituted-6-nitroquinolin-4(1H)-ones using Rink amide resin is described. Synthesis starts from immobilized 4-chloro-5-nitroanthranilic acid which, after the nucleophilic replacement of the chlorine atom with various amines and subsequent esterification with bromoacetophenones, afforded substituted phenacylanthranilates. Their cyclization by heating in sulfuric acid gave corresponding hydroxyquinolinones of excellent purity.

Ionization and fragmentation of monochloro-isomers of 3-hydroxy-2-phenyl-4(1H)-quinolinone.

Electron ionization (EI), methane chemical ionization (CI), and collision-induced dissociation (CID) mass spectra of complete series of positional monochloro-isomers of 3-hydroxy-2-phenyl-4(1H)-quinolinone are evaluated and discussed. It is shown that in the CI experiments, in addition to the protonated precursor molecules, odd-electron molecular ions are formed and this affects the appearance of the CID spectra. The influence of different direct probes and other experimental parameters such as the pressure of the reagent gas, isolation width, or collision energy was studied. EI, CI and CID spectra of the positional isomers show essentially the same fragmentation pathways but comparisons of the relative signal intensities of various product ions reveal some positional effects. Different isomers are also distinguished. The compounds can be divided into two groups using diagnostic ions (chloro substitution of the quinolinone moiety or the phenyl ring) or identified using a created spectral database. It was demonstrated that the reproducibility of the CID spectra is fully satisfactory for isomer identification, and that the created database can be applied for comparison of spectra measured over an extended time period (1 month) or spectra obtained during the direct analysis of a reaction mixture extract. Explanation of the fragmentation of the isomers is supported by exploratory density functional theory (DFT) calculations, e.g. rationalization of the relatively higher importance of the M+.-H.-Cl.-CO fragmentation pathway during EI than during CID, and vice versa for the pathway M+.-Cl.-CO.

Synthesis and cytotoxic activity of various 5-[alkoxy-(4-nitro-phenyl)-methyl]-uracils in their racemic form.

The preparation of various 5-[alkoxy-(4-nitro-phenyl)-methyl]-uracils with alkyl chain lengths C(1)-C(12) is described. The synthesis is based on the preparation of 5-[chloro-(4-nitro-phenyl)-methyl]-uracil and subsequent substitution of chlorine with appropriate alcohols. The resulting ethers were tested for their cytotoxic activity in vitro against five cancer cell lines. The compounds were less active in lung resistance protein expressing cell lines, suggesting the involvement of this multidrug resistant protein in control of the biological activity. Cytotoxic substances induced rapid inhibition of DNA and modulation of RNA synthesis followed by induction of apoptosis. The data indicate that the biological activity of 5-[alkoxy-(4-nitro-phenyl)-methyl]-uracils depends on the alkyl chain length.

Synthesis and cytotoxic activity of substituted 2-phenyl-3-hydroxy-4(1H)-quinolinones-7-carboxylic acids and their phenacyl esters.

The preparation of 3-hydroxy-2-phenyl-4(1H)-quinolinones substituted in position 7 with a carboxyl group is described. The synthesis is based on the reaction of 2-aminoterephthalic acid with substituted alpha-bromoacetophenones and subsequent cyclization of the resulting bisphenacylesters in polyphosphoric acid. The reaction affords a mixture of substituted 3-hydroxy-2-phenyl-4(1H)-quinolinones 7-carboxylic acids as well as their phenacylesters. All quinolinones prepared (acids and phenacylesters) were tested for cytotoxic activity in vitro against five cancer cell lines and the results and a tentative structure-activity relationship are reported.

Some new routes for the preparation of 3-amino-2-phenyl-4(1H)-quinolinones from anthranilamides.

[reaction: see text] Several new routes for the preparation of 3-amino-2-phenyl-4-1(H)-quinolinone 7a are compared. The most efficient is based on the cyclization of phenacyl anthranilamide 2a in the presence of (poly)phosphoric acid. The mechanisms of the rearrangements involved are discussed on the basis of the structures of isolated heterocyclic intermediates. The best methodology for the preparation of the title compound 7a was verified, and 10 other quinolinones 7 were prepared.