Micellar Form of a Ferrocene-Containing Camphor Sulfonamide with Improved Aqueous Solubility and Tumor Curing Potential.

The discovery of new anticancer drugs with а higher, more specific activity and diminished side effects than the conventional chemotherapeutic agents is a tremendous challenge to contemporary medical research and development. To achieve a pronounced efficacy, the design of antitumor agents can combine various biologically active subunits in one molecule, which can affect different regulatory pathways in cancer cells. We recently demonstrated that a newly synthesized organometallic compound, a ferrocene-containing camphor sulfonamide (DK164), possesses promising antiproliferative activity against breast and lung cancer cells. However, it still encounters the problem of solubility in biological fluids. In this work, we describe a novel micellar form of DK164 with significantly improved solubility in aqueous medium. DK164 was embedded in biodegradable micelles based on a poly(ethylene oxide)-b-poly(α-cinnamyl-ε-caprolactone-co-ε-caprolactone)-b-poly(ethylene oxide) triblock copolymer (PEO113-b-P(CyCL3-co-CL46)-b-PEO113), and the physicochemical parameters (size, size distribution, zeta potential, encapsulation efficiency) and biological activity of the obtained system were studied. We used cytotoxicity assays and flow cytometry to determine the type of cell death, as well as immunocytochemistry to assess the influence of the encapsulated drug on the dynamics of cellular key proteins (p53 and NFkB) and the process of autophagy. According to our results, the micellar form of the organometallic ferrocene derivate (DK164-NP) exhibited several advantages compared to the free substance, such as higher metabolic stability, better cellular uptake, improved bioavailability, and long-term activity, maintaining nearly the same biological activity and anticancer properties of the drug.

Structure and Conformational Mobility of OLED-Relevant 1,3,5-Triazine Derivatives.

A series of OLED-relevant compounds, consisting of 1,3,5-triazine core linked to various aromatic arms by amino group, has been synthesized and characterized. The studied compounds exist in solution as a mixture of two conformers, a symmetric propeller and asymmetric conformer, in which one of the aromatic arms is rotated around the C-N bond. At temperatures below -40 °C, the VT NMR spectra in DMF-d7 are in a slow exchange regime, and the signals of two conformers can be elucidated. At temperatures above 100 °C, the VT NMR spectra in DMSO-d6 are in a fast exchange regime, and the averaged spectra can be measured. The ratio of symmetric and asymmetric conformers in DMF-d7 varies from 14:86 to 50:50 depending on the substituents. The rotational barriers of symmetric and asymmetric conformers in DMF-d7 were measured for all compounds and are in the interval from 11.7 to 14.7 kcal/mol. The ground-state energy landscapes of the studied compounds, obtained by DFT calculations, show good agreement with the experimental rotational barriers. The DFT calculations reveal that the observed chemical exchange occurs by the rotation around the C(1,3,5-triazine)-N bond. Although some of the compounds are potentially tautomeric, the measured absorption and emission spectra do not indicate proton transfer neither in the ground nor in the excited state.

Molecular Insight into Mycobacterium tuberculosis Resistance to Nitrofuranyl Amides Gained through Metagenomics-like Analysis of Spontaneous Mutants.

We performed synthesis of new nitrofuranyl amides and investigated their anti-TB activity and primary genetic response of mycobacteria through whole-genome sequencing (WGS) of spontaneous resistant mutants. The in vitro activity was assessed on reference strain Mycobacterium tuberculosis H37Rv. The most active compound 11 was used for in vitro selection of spontaneous resistant mutants. The same mutations in six genes were detected in bacterial cultures grown under increased concentrations of 11 (2×, 4×, 8× MIC). The mutant positions were presented as mixed wild type and mutant alleles while increasing the concentration of the compound led to the semi-proportional and significant increase in mutant alleles. The identified genes belong to different categories and pathways. Some of them were previously reported as mediating drug resistance or drug tolerance, and counteracting oxidative and nitrosative stress, in particular: Rv0224c, fbiC, iniA, and Rv1592c. Gene-set interaction analysis revealed a certain weak interaction for gene pairs Rv1592-Rv1639c and Rv1592-Rv0224c. To conclude, this study experimentally demonstrated a multifaceted primary genetic response of M. tuberculosis to the action of nitrofurans. All three 11-treated subcultures independently presented the same six SNPs, which suggests their non-random occurrence and likely causative relationship between compound action and possible resistance mechanism.

Base-promoted direct amidation of esters: beyond the current scope and practical applications.

The base-promoted direct amidation of unactivated esters is among the most useful reactions for amide bond formation in contemporary organic chemistry. The intensive research in this area has led to the development of a number of new methods to achive this transformation. However, to date, the existing literature is more methodological and in many instances lacks practical directions. Therefore, the full potential of this transformation is yet to be revealed by broadening the substrate scope. In a search for new practical applications of the amidation reaction, herein we present a comprehensive study of a number of base-promoted direct amidations that encompass a wide range of amines and esters. Furthermore, we applied our findings in the synthesis of phosphoramidates and several industrially relevant products.

In Vitro Anticancer Activity of Two Ferrocene-Containing Camphor Sulfonamides as Promising Agents against Lung Cancer Cells.

The successful design of antitumour drugs often combines in one molecule different biologically active subunits that can affect various regulatory pathways in the cell and thus achieve higher efficacy. Two ferrocene derivatives, DK-164 and CC-78, with different residues were tested for cytotoxic potential on non-small lung cancer cell lines, A549 and H1299, and non-cancerous MRC5. DK-164 demonstrated remarkable selectivity toward cancer cells and more pronounced cytotoxicity against A549. The cytotoxicity of CC-78 toward H1299 was even higher than that of the well-established anticancer drugs cisplatin and tamoxifen, but it did not reveal any noticeable selective effect. DK-164 showed predominantly pro-apoptotic activity in non-small cell lung carcinoma (NSCLC) cells, while CC-78 caused accidental cell death with features characteristic of necrosis. The level of induced autophagy was similar for both substances in cancer cells. DK-164 treatment of A549, H1299, and MRC5 cells for 48 h significantly increased the fluorescence signal of the NFkB (nuclear factor 'kappa-light-chain-enhancer' of activated B-cells) protein in the nucleus in all three cell lines, while CC-78 did not provoke NFkB translocation in any of the tested cell lines. Both compounds caused a significant transfer of the p53 protein in the nucleus of A549 cells but not in non-cancerous MRC5 cells. In A549, DK-164 generated oxidative stress close to the positive control after 48 h, while CC-78 had a moderate effect on the cellular redox status. In the non-cancerous cells, MRC5, both compounds produced ROS similar to the positive control for the same incubation period. The different results related to the cytotoxic potential of DK-164 and CC-78 associated with the examined cellular mechanisms induced in lung cancer cells might be used to conclude the specific functions of the various functional groups in the ferrocene compounds, which can offer new perspectives for the design of antitumour drugs.

Chiral Aminoalcohols and Squaric Acid Amides as Ligands for Asymmetric Borane Reduction of Ketones: Insight to In Situ Formed Catalytic System by DOSY and Multinuclear NMR Experiments.

A series of squaric acid amides (synthesized in 66-99% isolated yields) and a set of chiral aminoalcohols were comparatively studied as ligands in a model reaction of reduction of α-chloroacetophenone with BH3•SMe2. In all cases, the aminoalcohols demonstrated better efficiency (up to 94% ee), while only poor asymmetric induction was achieved with the corresponding squaramides. A mechanistic insight on the in situ formation and stability at room temperature of intermediates generated from ligands and borane as possible precursors of the oxazaborolidine-based catalytic system has been obtained by 1H DOSY and multinuclear 1D and 2D (1H, 10/11B, 13C, 15N) NMR spectroscopy of equimolar mixtures of borane and selected ligands. These results contribute to better understanding the complexity of the processes occurring in the reaction mixture prior to the possible oxazaborolidine formation, which play a crucial role on the degree of enantioselectivity achieved in the borane reduction of α-chloroacetophenone.

Azo-hydrazone molecular switches: Synthesis and NMR conformational investigation.

A series of five intramolecularly hydrogen-bonded arylhydrazone (aryl = phenol, p-nitrophenol, anisole, quinoline) derived molecular switches have been synthesized and characterized by NMR and HRMS techniques. It was found that the compounds exist as different isomers in solution. An investigation of both conformational and/or configurational changes of the azo-hydrazone compounds was carried out by 1D 1 H- and 13 C- spectra, 2D NOESY, COSY, HSQC, and HMBC techniques. It was found that these stimuli-responsive molecular switches exist mainly in the E form by intramolecularly hydrogen bonded between NH and the pyridine nitrogen at equilibrium. Deprotonation of the neutral E form yields the E' deprotonated isomer. Prediction of 13 C-NMR chemical shifts was achieved by DFT quantum mechanical calculations. Anions have traditionally been difficult to calculate correctly, so calculations of the anion using different functionals, basis sets, and solvent effects are also included. Deuterium isotope effects on the 13 C-NMR chemical shifts were employed in the assignments and furthermore utilized as indicators of intramolecular hydrogen bonding. Studies in various organic solvents including CDCl3 , CD3 CN, and DMSO-d6 were also performed aiming to monitor dynamic changes over several days. The effect of the hydrogen bonded solvents leads to Z forms.

Anti-enteroviral activity of new MDL-860 analogues: Synthesis, in vitro/in vivo studies and QSAR analysis.

A series of 60 nitrobenzonitrile analogues of the anti-viral agent MDL-860 were synthesized (50 of which are new) and evaluated for their activity against three types of enteroviruses (coxsackievirus B1, coxsackievirus B3 and poliovirus 1). Among them, six diaryl ethers (20e, 27e, 28e, 29e, 33e and 35e) demonstrated high in vitro activity (SI > 50) towards at least one of the tested viruses and very low cytotoxicity against human cells. Compound 27e possesses the broadest spectrum of activity towards all tested viruses in the same way as MDL-860 does. The most active derivatives (27e, 29e and 35e) against coxsackievirus B1 were tested in vivo in newborn mice experimentally infected with 20 MLD50 of coxsackievirus B1. Compound 29e showed promising in vivo activity (protection index 26% and 4 days lengthening of mean survival time). QSAR analysis of the substituent effects on the in vitro cytotoxicity (CC50) and anti-viral activity of the nitrobenzonitrile derivatives was carried out and adequate QSAR models for the anti-viral activity of the compounds against poliovirus 1 and coxsackievirus B1 were constructed.

Synthesis and anti-enterovirus activity of new analogues of MDL-860.

A series of twelve novel compounds, analogues of antiviral agent MDL-860 were synthesized and their antiviral activity was evaluated in vitro against enteroviruses poliovirus 1 (PV1), Coxsackieviruses B1 (CVB1) and Coxsackieviruses B3 (CVB3). Compounds 14, 24 and 25 manifested strong antiviral effects against CVB1 and PV1 (SI values of 405 and 118 for CVB1 and PV1 respectively). In contrast to the wide anti-enteroviral activity of MDL-860, these three compounds were inactive against CVB3. Compounds 14, 24 and 25 along with MDL-860 were tested in vivo in mice infected with CVB1. Marked protective effects of compounds 14 and 24 were established, PI values of 50% and 33.3%, respectively. In addition, almost all of the tested compounds manifested very low toxicity.

Antimycobacterial activity generated by the amide coupling of (-)-fenchone derived aminoalcohol with cinnamic acids and analogues.

Aminoethyl substituted 2-endo-fenchol prepared from (-)-fenchone was used as scaffold for the synthesis of series of 31 amide structures by N-acylation applying cinnamic acids and analogues. The evaluation of their in vitro activity against Mycobacterium tuberculosis H37Rv showed for some of them promising activity-up to 0.2 µg/ml, combined with relatively low cytotoxicity of the selected active compounds.

Enantiopure antituberculosis candidates synthesized from (-)-fenchone.

The synthesis of new enantiopure N-acyl compounds derived from (-)-fenchone has been performed. The evaluation of their in vitro activity against Mycobacterium tuberculosis H37Rv showed for most of them moderate activity. The structures bearing sulfonamide functionality have comparable activity to ethambutol and possess low cytotoxicity.

Efficient synthesis of new (R)-2-amino-1-butanol derived ureas, thioureas and acylthioureas and in vitro evaluation of their antimycobacterial activity.

The synthesis of 22 structurally diverse urea, thiourea and acylthiourea derivatives containing the (R)-2-amino-1-butanol motif has been performed. The evaluation of their in vitro activity against Mycobacterium tuberculosis (H37Rv and strain 43) showed promising results in the case of the acylthiourea derivatives (MIC range 0.36-7.46 µM for H37Rv strain).

Synthesis and in vitro antimycobacterial activity of compounds derived from (R)- and (S)-2-amino-1-butanol - The crucial role of the configuration.

The synthesis of 47 structurally diverse compounds incorporating the (R)-2-amino-1-butanol motif has been realized. Ten of these compounds were found to exhibit in vitro specific activity against Mycobacterium tuberculosis H37Rv in a MIC range of 0.65 µM-14.03 µM. Five of the most active compounds 11, 22, 23, 31 and 42 (5.7-11.1 fold more active than ethambutol) can be outlined with very low cytotoxicity towards human embryonal kidney non-tumour cells (SI ranging from 91.2 to 375.4). For the purpose of comparison the (S)-enantiomers of these most active compounds have been synthesized and evaluated towards M. tuberculosis H(37)Rv showing no activity even at 20-32 fold higher concentrations.