Monika Pitucha

Synthesis, structure elucidation and antitumour activity of N-substituted amides of 3-(3-ethylthio-1,2,4-triazol-5-yl)propenoic acid.

New N-substituted amides of 3-(3-ethylthio-1,2,4-triazol-5-yl)propenoic acid (2-12) were designed and prepared by the condensation reaction of exo-S-ethyl-7-oxabicyclo-[2.2.1]-hept-5-ene-2,3-dicarbonyl isothiosemicarbazide (1) with primary amines. The chemical structure of all compounds was confirmed by IR, (1)H NMR, (13)C NMR spectra, the X-ray crystallography (for compounds 8, 11, 12) and elemental analysis. Moreover, compounds 9-11 were screened for their anticancer activity. Compounds 9 (in concentrations of 0.32 mM and 0.16 mM), 10 (in concentrations of 0.28 mM and 0.14 mM), and 11 (in concentrations of 0.35 mM and 0.17 mM) were found to be evidently effective in vitro against lung cell line (IC50). The distinctly marked antiproliferative effect of compounds 9 and 10 in breast carcinoma cells in vitro was ascertained. Moreover, the lowest cytotoxicity of compound 9 in concentrations of 0.16 mM and 0.03 mM against the normal skin fibroblast cell line and breast carcinoma cell in vitro after 24- and 48-h periods of incubation was noticed in this study.

An effective scaling frequency factor method for scaling of harmonic vibrational frequencies: Application to 1,2,4-triazole derivatives.

Scaling of harmonic frequencies of a molecule is one of the methods of improving the agreement between the calculated from a quadratic force field and experimental vibrational spectrum. An application of the recently proposed effective scaling frequency factor (ESFF) method to the complicated 1,2,4-triazole derivatives is presented. The calculations are based on the DFT/B3LYP/6-311G** quadratic force fields. It is shown that the ESFF method is capable of providing the high-quality spectra with regard to the scaled frequencies, comparable to these obtained with the well-established scaled quantum mechanical (SQM) force field method. Using the recommended scaling factors for the 11-parameter calculations, the RMS value obtained for a set of 293 vibrational modes of four compounds is only 8.7 and 8.5cm(-1), for SQM and ESFF, respectively, provided the hydrogen bonded C=O bond was excluded from the general non-hydrogen XX stretch group, and the scaling factor attributed to this bond was optimized. The new, 9-parameter set of scaling factors provides SQM- and ESFF-scaled frequencies that are of comparable quality to those of the 11-parameter calculations. In addition, it provides (on average) more reliable band splittings in the middle region of the spectrum, and the order of the scaled frequencies corresponds to that of the experimental bands. The straightforward application of the ESFF method to estimate the value of the scaled frequency is also presented.

Synthesis, Structure and Antibacterial Evaluation of Some N-substituted 3-amino-5-hydroxy-4-phenyl-1H-pyrazole-1-carboxamides

N-substituted 3-amino-5-hydroxy-4-phenyl-1H-pyrazole-1-carboxamide derivatives have been prepared by heterocyclization of 1-cyanophenyl acetic acid hydrazide with isocyanates. Representative compounds were evaluated as potential antimicrobial agents. The most promising compound in this series, the N-(1-naphthyl)-3-amino-5-hydroxy-4-phenyl-1H-pyrazole-1-carboxamide 2f, was the most effective against the reference strains of pathogenic S. aureus ATCC 25923 and S. aureus ATCC 6538 or opportunistic S. epidermidis ATCC 12228 with MIC value of 7.81 μg/ml and against the other gram-positive species with MIC values 15.63-31.25 μg/ml. This compound also showed high activity against clinical isolates of MSSA (methicillin-sensitive Staphylococcus aureus) with MIC of 0.98-31.25 μg/ml and MRSA (methicillin-resistant Staphylococcus aureus) with MIC of 1.96-7.81 μg/ml.

New Derivatives of 3-[(4-Phenyl-5-oxo-1,2,4-triazolin-1-yl)methyl]-4-substituted 1,2,4-Triazolin-5-one

In the reaction of hydrazide of (4-phenyl-5-oxo-1,2,4-triazolin-1-yl)-acetic acid (1) with isocyanate the respective semicarbazide derivatives (2) were obtained. Further cyclization with 2% NaOH led to the formation of [3-(4-phenyl-5-oxo-l,2,4-triazolin-l-yl)methyl]-4-substituted 1,2,4-triazolin-5-one (3) and (4-phenyl-5-oxo-1,2,4-triazolin-1-yl)acetic acid (4).

Synthesis, antibacterial and antiproliferative potential of some new 1-pyridinecarbonyl-4-substituted thiosemicarbazide derivatives

In this study, the antibacterial, cytotoxic and antiproliferative activities of novel thiosemicarbazide derivatives were assessed. Our results demonstrated that some of the novel compounds possess good antibacterial properties against Staphylococcus epidermidis, Streptococcus mutans and Streptococcussanguinis and are only slightly cytotoxic; thus, they exhibit an excellent therapeutic index, which is higher than that of ethacridine lactate. Moreover, our data showed that compounds 2 and 4 have an antiproliferative activity against human breast adenocarcinoma and human hepatocellular carcinoma cell lines. We expect that the novel thiosemicarbazide derivatives can be used as agents for treatment of dental caries and also for chemotherapy support.

Novel thiosemicarbazide derivatives with 4-nitrophenyl group as multi-target drugs: α-glucosidase inhibitors with antibacterial and antiproliferative activity

A series of thiosemicarbazides with 4-nitrophenyl group was obtained in the reaction of carboxylic acid hydrazides with isothiocyanates. All compounds were checked for their antibacterial and antiproliferative activity. Our results have shown that derivatives 6-8 possessed antibacterial activity against S. aureus, S. epidermidis, S. mutans and S. sanguinis, moderate cytotoxicity and good therapeutic safety in vitro. Additionally, compounds 1 and 4 significantly inhibited A549, HepG2 and MCF-7 cell division. Moreover, PASS software indicated that newly obtained compounds are potential α-glucosidase inhibitors. This was confirmed by in vitro studies. To investigate the mode of interaction with the molecular target compounds were docked to glucose binding site of the enzyme and exhibited a similar binding mode as glucose.

Structural and Molecular Docking Studies of 4-Benzyl-3-[(1-methylpyrrol- 2-yl)methyl]-4,5-dihydro-1H-1,2,4-triazol-5-one with Anticancer Activity

The 1,2,4-triazoles are an important group of medicinal substances which exhibit a wide range of activity, such as analgesic, antibacterial, fungicidal, antinflammatory, antiviral and anticancer. As a part of our long-term study on 1,2,4- triazoles we synthesize 4-benzyl-3-[(1-methylpyrrol-2-yl)methyl]-4,5-dihydro-1H-1,2,4-triazol-5-one which is characterized with anticancer activity. Here, we present an exhaustive studies of its electronic and molecular structure, aimed to rationalize the observed pharmacological activity, supported by the molecular docking to the EGFR kinase domain ATP binding site. The structural studies include X-ray analysis, experimental and computed spectral analysis (1H and 13C NMR, IR) as well as conformational analysis and the frontal molecular orbitals (FMO) analysis. The results of molecular docking indicate that interaction of 4-benzyl-3-[(1-methylpyrrol-2-yl)methyl]-4,5-dihydro-1H-1,2,4-triazol-5-one with the EGFR kinase domain ATP binding site may be responsible for the observed anticancer activity of this 1,2,4-triazole derivative. Moreover, we find that formation of the respective ligand-protein complex is conditioned by the keto-enol tautomerism of the ligand, i.e. the energetic prevalence of the keto form.

Determination of the Lipophilicity of Some New Derivatives of Semicarbazide and 1,2,4-Triazol-5-one with Potential Antibacterial Activity

The chromatographic behavior of new derivatives of 1,2,4-triazol-5-one and semicarbazide was determined. The lipophilicity was confirmed by the use of a RP-TLC method. The partition coefficients were calculated by use of theoretical procedures. The correlation between theoretical and experimental lipophilicity was determined. All obtained compounds were tested for their antimicrobial activity. Graphical Abstract Determination of the Lipophilicity of Some New Derivatives of Semicarbazide and 1,2,4-Triazol-5-one with Potential Antibacterial Activity

RP-TLC determination of the lipophilicity of some new derivatives of 1,2,4-triazole and thiosemicarbazide with potential antituberculosis activity

The reversed-phase thin layer chromatographic retention behavior of some new derivatives of 1,2,4-triazole and thiosemicarbazide has been determined. Linear relationships were established between the retention (RM) of each solute and the volume fraction of organic modifier (methanol or acetonitrile) in organic-aqueous mobile phases. This enabled determination of chromatographic lipophilic-ity data - RMW values by extrapolation, φ0 by interpolation for each organic modifier, and S denoting the slope of the linear dependences. Moderate correlation was established between chromato-graphic lipophilicity and log PG calculated by use of Chem Plus software. Experimental lipophilicity log PTLC was also determined for each solute by the use of a special calibration plot prepared by use of selected sulfonamide standards for the two mobile phase systems used in this study. The effect of different mobile-phase modifiers on experimentally obtained lipophilicity was studied and compared.

Novel Antibacterial Compounds and their Drug Targets - Successes and Challenges

Infectious diseases are one of the most important and urgent health problems in the world. According to the World Health Organization (WHO) statistics, infectious and parasitic diseases are a cause of about 16% of all deaths worldwide and over 40% of deaths in Africa. A considerable progress that has been made during last hundred years in the fight against infectious diseases, in particular bacterial infections, can be attributed mainly to three factors: (1) the general improvement of living conditions, in particular sanitation; (2) development of vaccines and (3) development of efficient antibacterial drugs. Although considerable progress in reduction of the number of cases of bacterial infections, especially in lethal cases, has been made, continued cases and outbreaks of these diseases persist, which is caused by different contributing factors. Indeed, during last sixty years antibacterial drugs were used against various infectious diseases caused by bacterial pathogens with an undoubtable success. The most fruitful period for antibiotic development lasted from 40s to 60s of the last century and resulted in the majority of antibiotics currently on the market, which were obtained by screening actinomycetes derived from soil. Although the market for antibacterial drugs is nowadays greater than 25 billion US dollars per year, novel antibacterial drugs are still demanded due to developed resistance of many pathogenic bacteria against current antibiotics. In the last five years, one can observe a dramatic increase in cases of resistant bacteria strains (e.g. Klebsiella pneumoniae and E. coli) which are responsible for difficult to treat pneumonia and infections of urinary tract. The development of resistant bacteria strains is a side effect of antibiotic application for treatment: the infections become untreatable as a result of the existence of antibiotic-tolerant persisters. In this review, we discuss the challenges in antibacterial drug discovery, including the molecular basis of drug resistance, drug targets for novel antibacterial drugs, and new compounds (since year 2010) from different chemical classes with antibacterial activity, focusing on structure-activity relationships.