Acta Chimica Slovenica最新文献

The coupling reaction of diazonium ion of 2-amino-6-nitrobenzothiazole at 0-5 °C with distinctly substituted 2-aminobenzothiazole derivatives produced new 1,2,3,5-tetrazine derivatives. It was found that diazotized 2-amino-6-nitrobenzo[d]thiazol reacts with the ring nitrogen atom of varyingly substituted 2-aminobenzothiazole derivatives to yield tetrazine nucleus. The benzene ring of benzothiazole bearing electron donor group and annelated to the tetrazine was further substituted in situ by other 6-nitrobenzo[d]thiazol-2-yl) diazinyl to yield the final product. The structure of the prepared compounds was elucidated using their physical, elemental, and spectroscopic data. The synthesized compounds were tested for their antimicrobial and antibiofilm activities against Staphylococcus aureus and Escherichia coli bacteria. Two of the synthesis tetrazine derivatives exhibited interesting antibiofilm potential.

This study aimed to develop a rapid method for separation of stigmasterol, campesterol and β-sitosterol in Prunus spinosa L. (sloe) fruit extracts by High Performance Liquid Chromatography system. Samples were prepared by Soxhlet extraction method and separated on a high strength silica C18 column using acetonitrile-methanol mobile phase and Photodiode Array Detector. The optimized method resulted in a linear calibration curve ranging from 1.7 ng mL-1 to 130 ng mL-1 for all three phytosterols. Analyses of internal and external phytosterol standards showed good linearity (R2 of 0.998 to 0.999); LOD and LOQ were determined to be 2.33×10-7-2.18×10-4 and 7.07×10-7-6.60×10-4 mg mL-1, respectively. Repeatability and reproducibility precision analyses showed acceptable values of RSD %. β-sitosterol was the predominant phytosterol (51.53-81.03 % of total) among all samples. Method validation parameters indicated that this analytical method can be applied for accurate and precise determination of campesterol, stigmasterol and β-sitosterol, in selected extracts.

Four bifunctional, noncovalent amine-squaramide organocatalysts were prepared from camphor in five steps. The stereochemistry of the prepared catalysts was thoroughly analyzed using various spectroscopic techniques. Their organocatalytic activity was investigated in the Michael addition of acetylacetone to trans-β-nitrostyrene. The addition product was formed in complete conversion and with an enantioselectivity of up to 77% ee. In the reactions catalyzed by the 2-exo-3-endo catalysts, the major (S)-enantiomer was formed, whereas in the presence of 2-endo-3-endo catalysts, the (R)-enantiomer was formed as the major product.

Combined in silico strategy for molecular mechanisms exploration of a series 3H-thiazolo[4,5-b]pyridin-2-ones exhibiting strong anti-exudative action through QSAR analysis, molecular docking and pharmacophore modelling is reported. GA-ML technique was used for QSAR models generation with 2D autocorrelation descriptors. One- and two-parameter regressions revealed that certain structural patterns or heteroatoms contribute mutually to the anti-exudative activity potentiation. Possible action mechanisms were discovered through flexible docking simulations with cyclooxygenase pathway enzymes (COX-1, COX-2, mPGES-1). Docking results indicated the possibility of stable complexes formation with the effective docking scores and proper orientation of ligands within the enzymes active sites. Pharmacophore modelling was carried out using protein-ligand interaction fingerprints methodology. Two- and three-centre 3D pharmacophore queries were constructed. Their analysis indicated the functionality of bicyclic thiazolopyridine scaffold proved by the steric placement of heteroatoms in the corresponding pharmacophore centres.

Quinoline and its derivatives are a family with unique medicinal properties, including antibacterial effects. It was assumed that the four Quinoline Derivatives Q1 , Q2, Q3 and Q4 had significant activity against pathogenic bacteria. These compounds were synthesized and characterization by TLC, IR, 1H-NMR, and 13C-NMR analyses. The biological activity of compound Q1 was IZ (19 ± 0.22) against Klebsiella pneumoniae, IZ (18 ± 0.22) against Bacillus subtilis, IZ (17 ± 0.22) against Staphylococcus aureus. Q2 was IZ (18 ± 0.22) against both Klebsiella pneumoniae and Bacillus subtilis. Q3 was IZ (17 ± 0.22) against staphylococcus aureus. Q4 was IZ (21 ± 0.22), where showed a higher inhibitory activity against E. coli, than that of ciprofloxacin. These results demonstrate the potential of the synthesized compounds to work as antibacterial drugs against these strains by inhibiting or deactivating the target proteins.

Three new copper(II) complexes, [CuClL] (1), [CuBrL]n (2) and [CuL(NCS)]n (3), derived from the Schiff base 2,4-dichloro-6-((2-pyrrolidin-1-ylethylimino)methyl)phenol (HL) have been prepared and characterized by spectroscopy methods, as well as single crystal X-ray determination. The Cu atom in complex 1 is in square planar coordination, and those in complexes 2 and 3 are in square pyramidal coordination. The Schiff base ligand coordinates to the Cu atoms through phenolate oxygen, imino nitrogen and pyrrolidine nitrogen. The antibacterial activities of the Schiff base and the three copper complexes have been assayed on the bacteria Staphylococcus aureus and Escherichia coli, and the yeast Candida parapsilosis.

Two new oxidovanadium(V) complexes, [VO2L1] (1) and [V2O2(μ-O)2L2)] (2), where L1 and L2 are the deprotonated form of 5-bromo-2-(((2-(pyrrolidin-1-yl)ethyl)imino)methyl)phenol (HL1) and 5-bromo-2-(((2-((2-hydroxyethyl)amino)ethyl)imino)methyl)phenol (HL2), respectively, have been synthesized and structurally characterized by physico-chemical methods and single crystal X-ray determination. X-ray analysis indicates that the V atom in complex 1 is in square pyramidal coordination, and those in complex 2 are in octahedral coordination. Crystal structures of the complexes are stabilized by hydrogen bonds. The catalytic property for epoxidation of styrene by the complexes was evaluated.

A new phenanthroline derivative bearing imidazole group, (2-(3,5-di(pyridin-4-yl)phenyl)-1-p-tolyl-1H-imidazo[4,5-f][1,10]phenanthroline) (1), has been devised. 1 can be used as a multifunctional probe exhibiting a highly sensitive colorimetric response to Fe2+ and a selectively ratiometric fluorescent response to Zn2+ in a buffer-ethanol solution. The absorption enhancement accompanied by a visual color change from colorless to red upon addition of Fe2+, makes 1 a suitable naked-eye sensor for Fe2+. Moreover, 1 displayed a Zn2+-induced red-shift of emission (44 nm) showing a color change from blue to light cyan under a 365-nm UV lamp. Its practical imaging applicability for intracellular Zn2+ was confirmed in HeLa cells using a confocal microscope. The improved emission properties and cell imaging capability would provide a new approach for fluorescence sensation for Zn2+.

A new azo compound [2-((4-hydroxy-3-(E)-(2-hydroxy-5-nitrophenyl)diazenyl)benzaldeyde and the azo schiff derivative [2-((4-hydroxy-3-((E)-(2-hydroxy-5-nitrophenyl)diazenyl)benzylidene)amino)-4-nitrophenol (Azo-S) has been synthesized. 13C-NMR, 1H-NMR, FT-IR, Mass apectroscopy and Uv-Visibl analysis was used to characterized new compounds. The new synthesized compound Azo-S was utilized to inhibit mild steel (MS) corrosion at little concentrations (0.001-0.006) M. Weight loss measurements studies in 1 M HCl and at 298 K  showed that Azo-S has a good corrosion inhibition efficiency, 75%  at 0.002 M of inhibitors.It was found that adsorption methods follow Lanngmuir isotherm with ΔG values around -23.8 kJ/mol, this confirms that a stable protective film is formed for the mild steel spontaneously during physical adsorption.

Breast cancer cell growth is often dependent on the presence of steroidal hormones. The 17β-hydroxysteroid dehydrogenase type 1 isoform (17βHSD1) catalyzes NADPH-dependent conversion of estrone to estradiol, a more potent estrogen, and represents potential drug target for breast cancer treatment.  To provide active enzyme for inhibitor screening, 17βHSD1 is usually expressed in insect or mammalian cells, or isolated from human placenta. In the present study we describe a simple protocol for expression and purification of active human 17βHSD1 from BL21(DE3) Escherichia coli cells. Soluble human 17βHSD1 was expressed using a pET28a(+)-based plasmid, which encodes a hexahistidine tag fused to the N-terminus of the protein, and purified by nickel affinity chromatography. The enzyme activity of purified 17βHSD1 was verified by three methods: thin-layer chromatography, an alkali assay and a spectroscopic assay. These non-radioactive enzyme assays require only standard laboratory equipment, and can be used for screening compounds that modulate 17βHSD1 activity.