Synthesis of Biologically Active 4-Oxo-4H-Chromene Derivatives Containing Sulfur-Nitrogen Heterocycles

The synthesis of 4-oxo-4H-chromenes containing sulfur-nitrogen heterocyclic rings as well as their biological activities are reviewed.     

Silver coordination compounds with antimicrobial properties

Silver and its compounds have long been known to possess antimicrobial properties. We report here on our observations in this field of research, namely on silver coordination compounds, and in particular polymers, which can be used in the medical field. An overview of the structural diversity of coordination compounds with a particular class of organic ligands is given, together with their properties, with a special focus on antimicrobial activity, solubility and light stability. Copyright © 2013 John Wiley & Sons, Ltd.     

Antifungal activities of amino acid ester functional pyrazolyl compounds against Fusarium oxysporum f.sp. albedinis and Saccharomyces cerevisiae yeast

Series of functional multidendate ligands based on pyrazole and amino acid derivatives were prepared in good and excellent yields (75–5%) by condensation of one equivalent of amino acid ester hydrochloride substrates with two equivalents of (3,5-dimethyl-1H–pyrazol-1-yl)methanol. These tridentate functionalized compounds and their starting materials were screened for their antifungal activities against Fusarium oxysporum f.sp. albedinis and the yeast of Saccharomyces cerevisiae. Considerable activities were recorded with respect to the two studied microorganisms.     

Synthesis of mono-, bis-spiro- and dispiro-β-lactams and evaluation of their antimalarial activities

Some new mono-, bis-spiro- and dispiro-β-lactams have been synthesized from imines derived from 9H-fluoren-9-one and a ketene derived from 9H-xanthene-9-carboxylic acid or phenoxyacetic acid by a [2+2] cycloaddition reaction in good to excellent yields varying from 45 to 83%. The biological activity of these monocyclic β-lactams was successfully investigated against Plasmodium falciparum K14 resistant strain with excellent EC₅₀ values up to 5 μM.     

New transition metal complexes of 9,10‐phenanthrenequinone p‐toluyl hydrazone Schiff base: Synthesis,spectroscopy, DNA and HSA interactions,antimicrobial, DFT and docking studies

The new complexes of Cu (II) and Ni (II) of a tridentate Schiff base ligand derived from 9,10‐phenanthrenequinone and p‐toluic hydrazide have been synthesized and characterized by elemental analysis, electrical conductometry, FT‐IR, Mass, NMR and UV–Vis. The DFT calculations were carried out at B3LYP/6‐31G*(d) level for the determination of the optimized structure of the ligand and its complexes. The as‐synthesized compounds were screened for their antimicrobial activity. Also, their binding behavior with fish salmon‐DNA (FS‐DNA) and human serum albumin (HSA) were studied by different kinds of spectroscopic and molecular modeling techniques. The fluorescence data at different temperatures were applied in order to estimate the thermodynamics parameters of interactions of ligand and its complexes with DNA and HSA. The results showed that the as‐made compounds could bind to FS‐DNA and HSA via the groove binding as the major binding mode. According to molecular docking calculation and competitive binding experiments, these compounds bind to the minor groove of DNA and hydrophobic residues located in the subdomain IB of HSA. In addition, the molecular docking results kept in good consistence with experimental data.     

Antimicrobial activity of novel isothiuronium salts with 7-chloro-4,6-dinitrobenzofuroxan-5-olate anion

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The impact of preventive activities on the economics of production systems: Modeling and application

In this paper, the impact of preventive activities on the economics of production systems has been discussed. A defective production system has been used to evaluate the financial return of a system with and without preventive activity. A mathematical model has been developed to simulate the situation. A practical case in the automotive industry has been used to verify the model. According to this research, it has been found that preventive activities will affect the return of the production system, and the effect depends on the cost of the action that has been taken.     

Stereoselective Synthesis,Characterization, and Antibacterial Activities of Novel Isosteviol Derivatives with D‐Ring Modification

Considerable interests have been attracted by isosteviol and its derivatives because of their large variety of bioactivities. In this project, a series of novel 15‐ and 16‐substituted isosteviol derivatives were stereoselectively prepared by means of functional interconversions in ring D of the tetracyclic diterpene isosteviol. All compounds synthesized were characterized by analysis of NMR, IR, HR‐MS data, and the configurations of 33 and 37 were confirmed by X‐ray crystallographic analysis. The antibacterial activities in vitro of these isosteviol derivatives were investigated; the synthetic compounds were more active against Gram‐positive than Gram‐negative bacteria, and were especially active against Bacillus subtilis. Among them, compound 27 (MIC=1.56 μg/ml) exhibited the highest antibacterial activity and thus may be exploitable as a lead compound for the development of potent antibacterial agents.     

Structure elucidation,complete NMR assignment and PM5 theoretical studies of new hydroxy‐aminoalkyl‐α,β‐unsaturated derivatives of the macrolide antibiotic josamycin

Four new hydroxy‐aminoalkyl derivatives of α,β‐unsaturated macrolide‐josamycin (2–5) have been synthesised and their structures have been studied by means of ¹H and ¹³C NMR and FT‐IR methods. Complete assignment of resonances in the ¹H and ¹³C NMR spectra has been made on the basis of ¹H? ¹³C HSQC, ¹H? ¹³C HMBC, ¹H? ¹H COSY, ¹H? ¹H NOESY 2D experiments. Spectroscopic data indicated that for the derivatives 3 and 4 some equilibrium between two different structures exists in contrast to derivatives 2 and 5. The lowest‐energy structures of the new derivatives of josamycin have been calculated and visualised by PM5 method at semi‐empirical level of theory, taking into account the NMR and FT‐IR data. The most significant differences between the structures of josamycin and its newly synthesised derivatives' were found in the conformation of the macrolide aglycone part and in the mutual orientation of the 4‐O‐isovalerylmycarosylmycaminose moiety relative to the aglycone part. PM5 semi‐empirical calculations indicated that the structures of the new macrolide derivatives are stabilised by rather weak intramolecular hydrogen bonds in agreement with spectroscopic data. Antimicrobial properties of the new derivatives 2–5 as well as those having an acetate group at C‐3 (6 and 7) were determined and compared to that of the parent macrolide antibiotic josamycin (1). Copyright © 2010 John Wiley & Sons, Ltd.