Vol. 13 No. 4(52) (2015)

Published: 2015-12-27

Original Researches

  • The synthesis of 1,5-diaryl-4-arylthiopyrrolidin-2-ones by arylsulfenylation of styryl acetic acid N-arylamides

    N. M. Tsyzoryk, I. Yu. Danyliuk, A. I. Vaskevych, R. I. Vaskevych, M. V. Vovk
    3-5

    The role of the electrophilic intramolecular cyclization (EIC) reaction of unsaturated carboxylic acid amides has been described for the design of arylthio-containing lactams and lactones. In order to identify the effect of the styryl moiety on regioselectivity of the electrophilic intramolecular cyclization process styryl acetic acid amides with electron-donating substituents in para-position of the styryl moiety have been studied. It has been found that these compounds react with phenyl and p-tolylsulfenylchlorides in nitromethane in the presence of lithium perchlorate as a “doping additive” to form 1,5-diaryl-4-arylthiopyrrolidin-2-ones with the yield of 60-66%. It is most likely that the reaction found includes the formation of the episulfonium cation stabilized by the perchlorate-anion followed by 5-endo-cyclization onto the nitrogen atom of the amide group. The structure of the compounds synthesized has been confirmed by their spectral parameters. In particular, the IR-spectra contain strong absorption bands C=O at 1703-1703 cm-1, and 1H NMR-spectra of the compounds obtained are characterized by two protons multiple shifts of the H3 pyrrolidine ring at 2.52-2.64 and 3.08-3.22 ppm, respectively, H4 proton multiple shifts at 3.61-3.76 ppm and H5 at 4.99-5.09 ppm. Formation of the pyrrolidine ring as a result of cyclization has been reliably proven by 13C NMR-spectra with the typical signals of carbon atoms: C3 (37 ppm), C4 (48 ppm), C5 (69 ppm) and C2 (172 ppm).

    DOI: https://doi.org/10.24959/ophcj.15.870
  • Methylation of position 8 in the pyridine moiety of the N-(benzyl)-2-hydroxy-4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carboxamide molecule as an attempt to enhance their analgesic properties

    I. V. Ukrainets, O. V. Gorokhova, L. V. Sydorenko, S. G. Taran
    6-11

    The chemical modification of the pyridine moiety of the molecule – displacement of the methyl group in position 8 of pyrido[1,2-a]pyrimidine nucleus has been considered as one of the possible versions to optimize the biological properties of N-(benzyl)-2-hydroxy-4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carboxamides. The synthesis of the research targets was carried out by the reaction of the corresponding benzylamines and ethyl 2-hydroxy-8-methyl-4-oxo-4H-pyrido[1,2-a] pyrimidine-3-carboxylate, in its turn obtained by condensation of 2-amino-4-methylpyridine (i.e. the product with the methyl group in the intentionally required position) and triethyl methanetricarboxylate. The structure of the compounds obtained has been confirmed by the data of elemental analysis and NMR 1H spectroscopy, and in the case of optically active 1-phenylethylamides additionally by polarimetry. The study of the analgesic properties of all N-(benzyl)-2-hydroxy-8-methyl-4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carboxamides was performed on the standard experimental “acetic acid writhing” model. At the same time, it has been found that our modification is accompanied with the increased biological activity of exclusively para-substituted derivatives. For profound research 4-fluorobenzylamide exceeding Piroxicam and Nabumetone by the level of the specific effect has been recommended as a potential new analgesic.

    DOI: https://doi.org/10.24959/ophcj.15.858
  • A convenient way of 3-fluoro-1,8-naphthalimide synthesis

    N. F. Fedko, V. F. Anikin
    12-15

    The syntheses of 3-fluoro-1,8-naphthalimide and 3-fluoro-1,8-naphthalic anhydride from 3-nitro-1,8-naphthalimide have been described. 3-Nitro-1,8-naphthalimide can be obtained by nitration of naphthalimide with sodium nitrate in sulfuric acid. Stability of naphthalimides under acidic and alkaline conditions makes 3-substituted naphthalimides more suitable synthones for further functionalization compared to the corresponding 3-substituted naphthalic anhydrides. The best yield of 3-fluoro-1,8-naphthalimide was achieved through the following sequence: 1) nitration of naphthalic anhydride to 3-nitronaphthalic anhydride by sodium nitrate in the concentrated sulfuric acid; 2) ammonolysis of 3-nitronaphthalic anhydride to 3-nitronaphthalimide with aqueous ammonia; 3) reduction of 3-nitronaphthalimide to 3-amino-naphthalimide with sodium dithionite solution in aqueous ethanol; 4) preparation of 3-fluoronaphthalimide by diazotization of 3-aminonaphthalimide and subsequent thermal decomposition of the corresponding tetrafluoroborate. Nitration of naphthalic anhydride makes it possible to avoid the problem of poor solubility of naphthalimide in sulfuric acid. Subsequent reactions are conveniently carried out with naphthalimide derivatives, thus avoiding the difficulties encountered in isolating of 3-aminonaphthalic anhydride that can undergo a polymerization reaction. The new protocol is more efficient than the preparation route previously described leading to 3-substituted naphthalic anhydrides and naphthalimides by virtue of the substitution reaction at C-4 of acenaphthene followed by oxidation.

    DOI: https://doi.org/10.24959/ophcj.15.857
  • Testing of a new docking scoring function on the example of inhibitors of protein tyrosine phosphatase 1B

    V. Yu. Tanchuk, V. O. Tanin
    16-19

    A new scoring function H1 recently developed for molecular docking has been tested on the complexes of protein tyrosine phosphatase 1B (PTP1B) from the PDB data bank and using docking of a set of inhibitors from the NIH database. The function is based on the scoring functions of AutoDock and AutoDock Vina and is implemented in the modified version of the AutoDock. The function performed well both in the case of the complexes from the PDB databank and in a real docking process. Calculation of pKi for the complexes from the PDB databank was very accurate. The molecular docking has been done with a modified version of AutoDock that uses spatial constraints and a new search engine. Energies of complexes were minimized, and pKi values of the resulting complexes were estimated by the new scoring function. As shown previously, conformations of PTP1B in complexes with ligands can be divided into five clusters. All five typical conformations of PTP1B binding pocket were used for docking. Better docking results were obtained on the clusters with open WPD loop though some compounds could not be docked well to such conformations of the enzyme. The function has shown a good “scoring power” (i. e. the ability to predict pKi values) and “screening power” (the ability to enrich top 10 or 20% of predictions by real active compounds) thus proving to be suitable for the virtual screening of potential PTP1B inhibitors. The performance of the new scoring function H1 was much better than that of the original scoring function of AutoDock tested earlier.

    DOI: https://doi.org/10.24959/ophcj.15.862
  • Synthesis and the antimicrobial activity of 3-(2-methyl-4-oxo-1,4-dihydroquinoline-3-yl)propanoic acids

    V. O. Zubkov, T. P. Osolodchenko, N. I. Ruschak, O. L. Kamenetska, O. V. Kiz
    20-26

    In order to reveal the possible regularities of the structure–activity relationship the derivatives of 3-(2-methyl-4- oxo-1,4-dihydroquinoline-3-yl)propanoic acid having various substituents in α-position of the acidic moiety of propanoic acid such as alkyl, carboxyl, acyl and acetamide substituents have been synthesized. The synthesis of the target compounds has been carried out using 3-dimethylaminomethyl-2-methyl-1,4-dihydroquinoline-4-one as a versatile alkylating reagent. Its interaction with methylene active substances allowed to obtain monoalkyldicarbonyl compounds, which further hydrolysis gave the derivatives of 3-(2-methyl-4-oxo-1,4-dihydroquinoline-3yl)propanoic acid. The structures of the compounds obtained have been confirmed by the data of 1H NMR and elemental analysis. The results of the screening performed by the agar diffusion method have shown different levels of the antimicrobial activity. For two compounds – 1,3-diethoxy-2-[(2-methyl-4-oxo-1,4-dihydroquinolin-3-yl)methyl]-1,3-dioxopropan-2-yl-carbamic acid and 3-(2-methyl-4-oxo-1,4-dihydroquinolin-3-yl)propanoic acid a moderate broad-spectrum activity has been found in the screening method. The results of the research have shown the perspectiveness of further search for novel antibacterial agents based on 4-quinolon-3-yl-propanoic acids, therefore, it is necessary to expand the range of the compounds with this scaffold.

    DOI: https://doi.org/10.24959/ophcj.15.869
  • The synthesis and anticancer properties of 2-(4-amino-5-methyl-4H-[1,2,4]triazol-3-ylsulfanyl)-N-(5-R-benzylthiazol-2-yl)-acetamides

    Yu. V. Ostapiuk, V. S. Matiychuk, M. D. Obushak
    27-31

    3-Aryl-2-chloropropanals 2a-h have been prepared by the reaction of arenediazonium chlorides 1a-h with acrolein in the conditions of Meerwein arylation (water-acetone, CuCl2 as a catalyst). These aldehydes react with thiourea by refluxing in ethanol to obtain 2-amino-5-R-benzyl-1,3-thiazoles 3a-h (R = 2-Cl, 3-Cl, 4-Cl, 3-CF3, 2,4-Cl2, 2,5-Cl2, 3,4-Cl2, 3-Cl-4-Me) with high yields. The resulting 2-aminothiazoles were acylated with chloroacetic acid chlorides to form 2-chloro-N-(5-aryl-1,3-thiazol-2-yl)acetamides 4a-h with the yields of 68-91%. By the reaction of compounds 4a-h with 4-amino-5-methyl-4H-1,2,4-triazole-3-thiole 5 a series of novel 2-(4-amino-5-methyl-4H-[1,2,4]triazol-3-ylsulfanyl)-N-(5-R-benzylthiazol-2-yl)-acetamides 6a-h (71-86%) have been synthesized. These compounds have been evaluated for their anticancer activity against 60 cancer lines in the concentration of 10 μM. The human tumour cell lines were derived from nine different cancer types: leukemia, melanoma, lung, colon, CNS, ovarian, renal, prostate, and breast cancers. Among all the derivatives, compounds 6a-c, 6e,f (R = 2-Cl, 3-Cl, 4-Cl, 2,4-Cl2, 2,5-Cl2) have been found to be active and have a high selectivity in relation to melanoma, while 2-(4-amino-5-methyl-4H-[1,2,4] triazol-3-ylsulfanyl)-N-[5-(2-chlorobenzyl)-thiazol-2-yl]-acetamide (6a) and 2-(4-amino-5-methyl-4H-[1,2,4]triazol-3-ylsulfanyl)-N-[5-(3,4-dichlorobenzyl)-thiazol-2-yl]-acetamide (6g) are active in relation to breast cancer.

    DOI: https://doi.org/10.24959/ophcj.15.865
  • The synthesis, reactivity and the antimicrobial activity of substituted thieno[2,3-d]pyrimidine-4(3H)-thio(seleno)nes

    D. O. Kolomieitsev, V. I. Markov, V. O. Astakhina, S. I. Kovalenko, S. A. Varenichenko, O. V. Kharchenko
    32-38

    A new series of R1,R2-thieno[2,3-d]pyrimidine-4(3H)-one, thione and selenone derivatives have been synthesized; the reaction of alkylation of the compounds obtained has been studied. Their structures have been confirmed by the NMR 1H and mass spectra, and elemental analysis. The antibacterial and antifungal activities in vitro against three bacterial and two fungal pathogens have been revealed using the stiff plate agar diffusion method and the serial dilution method. The minimal bactericidal, fungicidal and bacteriostatic concentrations have been obtained. The pharmacological screening has shown that some of the compounds obtained possess a good antimicrobial activity. The culture of S.aureus. appeared to be the most sensitive to compound 10a. The best fungistatic indicators against A.niger have been found for compounds 4a and 9a.

    DOI: https://doi.org/10.24959/ophcj.15.866
  • The study of regularities of the structure – analgesic activity relationship in a series of 4-hydroxy-Nn-(pyridin-2-yl)-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxamides

    I. V. Ukrainets, L. A. Petrushova, O. V. Gorokhova, O. O. Davydenko
    39-43

    Continuing the search for new analgesics and with the purpose of revealing the structural-biological regularities, which are important for further studies, the synthesis of a series of 4-hydroxy-N-(pyridin-2-yl)-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxamides unsubstituted in position 1 has been carried out. The structure of all compounds synthesized has been confirmed by elemental analysis, 1H NMR spectra and mass spectra. Based on a detailed analysis of the mass spectra it has been concluded that 4-hydroxy-N-(pyridin-2-yl)-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxamides in crystals are inner salts – 3-{[(pyridinium-2-yl)amino]carbonyl}-2,2-dioxo-1H-2,1-benzothiazin-4-olates. It has been noted that spectroscopy of 1H NMR does not allow either to confirm or disprove that in DMSO solution the substances studied exist in the form of inner salts since the signals of the active protons of OH and NHgroups that are important do not appear. According to the results of the pharmacological screening the substances – for example, 3-{[(6-methylpyridinium-2-yl)amino]carbonyl}-2,2-dioxo-1H-2,1-benzothiazin-4-olate – exceeding Piroxicam by the analgesic activity have been found. It has been unequivocally determined that removal of the 1-N-methyl group from the structure of 4-hydroxy-1-methyl-N-(pyridin-2-yl)-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxamides in general leads to a marked decrease in analgesic properties and may be considered inappropriate.

    DOI: https://doi.org/10.24959/ophcj.15.864
  • The complexing ability of n-substituted thiourea derivatives as chelating ligands in the reaction with PdCl2

    Yu. L. Zborovskii, V. V. Orysyk, D. O. Melnychenko, S. I. Orysyk, H. H. Repich, L. V. Garmanchuk, L. I. Palchykovska, V. I. Pekhnyo, M. V. Vovk
    44-49

    The complexation reactions of N-substituted thiourea derivatives with PdCl2 have been investigated in the present work. The functionally substituted thiourea derivatives are found to be effective chelating agents, in which the nature of substituents has a significant impact to the compositions and structures of complexes. Thus, (N-pyridine-2-yl)thioureas in the interaction with PdCl2 form two types of complexes in the molar ratio of M:L 1:1 and 1:2, in which they act as S,N-bidentate ligands coordinated to the palladium ion by thione sulphur and the nitrogen atom of the pyridine ring. The reaction of N-allylthioureas with PdCl2 in the equimolar ratio results in formation of the π-complexes where the ligands are coordinated by the thione sulphur and the C=C double bond of the allylic moiety. The preparative methods for the synthesis of this type of complexes have been developed. The composition of the products synthesized and the ligands coordination mode have been determined by elemental analysis and 1H NMR spectroscopy. Furthermore, the structure of compounds 4, 5 has been confirmed by the X-ray diffraction study. The biomedical studies have proven that the complex compounds 5 and 6 in vitro have the cytostatic and cytotoxic activity against tumour HeLa cells.

    DOI: https://doi.org/10.24959/ophcj.15.868
  • 5,6-Dihydro-[1,2,4]triazolo[1,5-c]quinazolines. Message 1. Features of interactions between [2-(3-aryl-1H-1,2,4-triazole-5-yl)phenyl]amines, aliphatic and aromatic aldehydes

    S. V. Kholodnyak, K. P. Schabelnyk, O. Yu. Voskoboynik, G. G. Berest, S. I. Kovalenko
    50-56

    Reactions of [5+1]-cyclocondensation of [2-(3-aryl-1H-1,2,4-triazol-5-yl)phenyl]amines with aliphatic and aromatic aldehydes produce the corresponding 5-R-2-aryl-5,6-dihydro- or 5-R-2-aryl-[1,2,4]triazolo[1,5-с]quinazolines depending on the conditions. The optimal conditions of the reaction have been found, and factors contributing to oxidation of 5-R-2-aryl-5,6-dihydro-[1,2,4]triazolo[1,5-с]quinazolines have been determined. The alternative synthetic approaches for 5-R-2-aryl-[1,2,4]triazolo[1,5-с]quinazolines, namely oxidation of their reduced analogues and interaction of [2-(3-aryl-1H-1,2,4-triazol-5-yl)phenyl]amines with acylhalides of aliphatic or aromatic carboxylic acid have been proposed. Purity and the structure of the compounds synthesized have been confirmed by the complex of physicochemical methods, including LC-MS, 1H-, 13C NMR, mass-spectrometry and elemental analysis. The peculiarities and differences of 1H- and 13C-NMR spectral patterns of 5-R-2-aryl-5,6-dihydro-[1,2,4]triazolo[1,5-c]quinazolines and their aromatic analogues have been described.

    DOI: https://doi.org/10.24959/ophcj.15.867
  • The synthesis and evaluation of the bactericidal activity of 4-(4-chloro-1H-imidazol-5-yl)-2-oxo-1,2-dihydropyridin-3-carbonitriles

    O. Ya. Mel’nyk, V. O. Chornous, N. D. Yakovychuk, N. V. Mel’nichenko, M. V. Vovk
    57-61

    The synthetic approach to preparation of some new 4-imidazolyl substituted derivatives of pyridine-3-carboxylic acid nitriles has been proposed, and their antimicrobial and antifungal properties have been studied in the article. It has been found that 4-(4-chloro-1H-imidazol-5-yl)-2-oxo-1,2-dihydropyridin-3-carbonitriles are prepared with 41-51% yields by four component cyclocondensation of 4-chloroimidazol-5-carbaldehydes with acetophenones and ethyl cyanoacetate in the presence of the 10-fold excess of ammonium acetate when boiling in ethanol for 15-30 h. A detailed monitoring of the reaction by liquid chromatography–mass spectrometry has shown that the reaction is accompanied with the by-process forming the corresponding chalcones that do not tend to undergo cyclization to the target products. The structure of the compounds synthesized has been proven by the complex of physical and chemical methods: IR, 1H and 13C NMR spectroscopy and liquid chromatography–mass spectrometry. The most evidential among them are 13C NMR spectra with characteristic signals for the pyridоne system in such ranges as C3 (90-92 ppm), C5 (115-116 ppm), C4 (127-129 ppm), C6 (144-146 ppm) and C2 (159-161 ppm). The results of the bactericidal activity study of a number of the compounds synthesized have convincingly confirmed their high antimicrobial and antifungal action. They inhibit the growth of microorganism vegetative forms in the concentrations of 7.8-125 mg/ml.

    DOI: https://doi.org/10.24959/ophcj.15.860
  • Development and validation of the method for determination of related impurities in riboxin tablets

    M. V. Rosada, N. Yu. Bevz, V. A. Georgiyants
    62-67

    Riboxin (inosine) is used in medicine for treating cardiovascular diseases, so the number of dosage forms containing this substance as an active ingredient is constantly increasing at the Ukrainian pharmaceutical market. When developing quality control methods for a dosage form containing one active substance it is advisable to carry out tests on the presence of related impurities besides identification and assay tests. The article presents the data concerning development of the method for determination of related impurities (hypoxanthine, guanosine) in riboxine tablets using HPLC. The analysis was carried out using a HPLC column (125×4 mm i.d., 5 μm particles) filled with “Lichrospher 60 RP select B”sorbent. The mobile phase adjusted with the phosphate buffer to pH 3.5 was used. The UV detection was performed at 250 nm. The validation characteristics have been studied using the acceptance criteria for the tolerances of the content not more than 0.5% for each impurity, and they confirm specificity (the absence of the effect of excipients), linearity, precision (convergence), accuracy (Δz = 0.79≤max Δz = 5.0, δ = 0.21≤max δ = 0.26, a = 0.48, r = 0.99997>0.9976 for hypoxanthine, and Δz = 0.83≤max Δz = 5.0, δ = 0.17≤max δ = 0.28, a = 0.21, r = 0.99997>0.9976 for guanosine), and the application range for the method proposed.

    DOI: https://doi.org/10.24959/ophcj.15.863
  • The study of retention regularities for the potential drug substances of 1,2,4-triazol-3-ylthioacetic acids and their salts series by the method of HPLC/DAD-MS

    B. O. Varynskyi, Ye. G. Knysh, V. V. Parchenko, A. G. Kaplaushenko
    68-75

    The derivatives of 1,2,4-triazole are potential drug substances with various biological activity. The control of stages for obtaining such compounds at the research and production phase is an important task of modern pharmaceutical science. HPLC/DAD-MS is the most universal and selective method, which allows to confirm the structure both of active substances and impurities and determine the content of analytes. The aim of the research is to study the dependence of the retention characteristic for the series of 1,2,4-triazol-3-ylthioacetic acids and their salts, which are the target products in the synthesis of the registered and potential drug substances by 8 synthetic schemes, on the content of acetonitrile in the mobile phase under the conditions of HPLC/DAD-MS determination. The dependence of the capacity factor k on the content of acetonitrile for 1,2,4-triazol-3-ylthioacetic acids and their salts has been determined. The possibilities of choice of conditions for determining these compounds both individually and in mixtures have been shown. It has been found that the reversed-phase retention mechanism for 1,2,4-triazol-3-ylthioacetic acids under study up to 65% content of acetonitrile in the eluent, and then the ion-exchange mechanism of interaction with silanol groups are observed. The exponential character of correlation between logD and capacity factors for the compounds tested has been determined for 15% content of acetonitrile in the mobile phase. It has been determined that correlation between logD and decimal logarithms of capacity factors for the compounds to be investigated has the linear character for 15% content of acetonitrile in the mobile phase.

    DOI: https://doi.org/10.24959/ophcj.15.859