Functionalization of 1,2,3-Triazole to Pyrimidine,Pyridine, Pyrazole,and Isoxazole Fluorophores with Antimicrobial Activity

Russian Journal of General Chemistry - The multi-component reaction of diacetyl triazole derivative with ethyl cyanoacetate and various aromatic aldehydes according to the conventional and solvent...     

Cyanoacetic acid hydrazide: An efficient access for the synthesis of multi-functional azine and azole derivatives

Herein, the synthesis of nitrogen-containing heterocyclic scaffolds from heterocyclization of cyanoacetic acid hydrazide derivatives is described. Thiosemicarbazide derivative 1a undergoes base-mediated cyclization producing pyrazole derivative of type 2 . The triazolopyridine 5 was obtained by double cyclization of 1a and benzylidene malononitrile. Compound 1b condensed with ethyl chloroformate to furnish pyrazolooxazine 8 . Compound 1b was added to benzoyl isothiocyanate under thermal condition to form oxadiazine derivative 10 while, keeping the above reactant under room temperature to form acyclic derivative 11 . Using CS₂ as a cyclizing agent for compound 1b yielded pyrazole derivative 13 . Treatment of 1b with I₂ resulted in oxidative cyclization producing pyridazine derivative 14 . Compound 1c cyclized with benzoyl isothiocyanate forming triazolothiazine derivative 18 . While using cinnamoyl isothiocyanate, the acyclic product 22 was obtained. Compound 1c was condensed with formaldehyde leading to oxadiazole derivative 25 .     

Bioactive Small Molecules Having a Fatty Residue. Part VI: Synthesis,Cytotoxicity Evaluation,and Molecular Docking Studies of New Pyrimidine Derivatives as Antitumor Agents

Russian Journal of Organic Chemistry - Difficultly accessible pyrimidine, thiazolopyrimidine, triazolopyrimidine, and thiazinopyrimidine derivatives containing an oleyl residue were synthesized via...     

Energy transfer and excited state lifetime of some anthracene laser dyes

The lifetimes of some anthrathene derivatives in different solvents have been determined using the phase modulation method. The lifetime of 10-phenyl-2-methyl-9-acetoxyanthracene and 10-(4-acetoxyphenyl)-2-methyl-9-acetoxyanthracene were found to equal 11 and 11 ns in methanol, respectively. Energy transfer from 10-phenyl-2-methyl-9-acetoxyanthracene and 10-(4-acetoxyphenyl)-2-methyl-9-acetoxyanthracene to rhodamine B and rhodamine 110 in different solvents has been studied by using steady-state emission measurements. The large values of the critical transfer distance R₀ and the rate constant of energy transfer k_ET suggest that the mechanism is long-range dipole–dipole energy transfer as described by Förster.     

Fluorimetric determination of iron(III) by quenching the luminescence of the zinc-morin-Triton X-100 system

Summary Simple and highly sensitive fluorimetric methods for iron determination are described. The methods are based on quenching the fluorescence of an aqueous morin solution or zinc-morin-Triton X-100 ternary system. The fluorescence emission is measured at 500 and 503 nm (wavelength of excitation 420 and 433 nm) for morin and the ternary system, respectively. The quenching calibration graphs are linear over the range 0–250 and 0–55 ng Fe/ml and the iron detection limits are 20 and 5 ng/ml using morin and zinc-morin-Triton X-100 system, respectively. The influence of experimental variables such as pH, reagent and surfactant concentrations, temperature, standing time and diverse ions are studied to obtain the optimum conditions. The method has been applied to the determination of iron in aluminium metal.

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Fluorimetrische Eisen(III)-bestimmung durch Luminescenzlöschung des Systems Zink-Morin-Triton X-100

     

ABSORPTION POLARIZATION PROPERTIES OF LIGHT-ADAPTED BACTERIORHODOPSIN IN THE 266–620nm REGION

Abstract— Using the method of polarized photochemistry, the polarization of the first daughter (K₆₁₀) in the photocycle of light-adapted bacteriorhodopsin (bR₅₇₀) is determined relative to the polarization of the photolysis pulse for different absorption regions of bR₅₇₀. The results are discussed in terms of recent spectroscopic assignments of bR₅₇₀, and in the 310–266 nm region, in terms of energy transfer processes between the apoprotein and the retinal.     

Flavonoids of Alcea rosea L. and their immune stimulant,antioxidant and cytotoxic activities on hepatocellular carcinoma HepG-2 cell line

Alcea rosea L. is widely cultivated in gardens of Egypt as an ornamental plant and it has a great history of folkloric medicinal uses. In the present work, phytochemical investigation of the alcoholic extract of the flowers of A. rosea L. led to the isolation of six flavonoids (1–6). Dihydrokaempferol-4′-O-β-d-glucopyranoside (1), dihydrokaempferol (2), kaempferol-3-O-[6″-(E-coumaroyl)]-β-d-glucopyranoside (3), kaempferol-3-O-β-d-glucopyranoside (4), Apigenin (5) and kaempferol-3-O-α-l-rhamnopyranosyl-(1′″→6″)-β-d-glucopyranoside (6). Four of the isolated compounds were evaluated for their antioxidant, immunostimulant and cytotoxic activities against HepG-2 cell line. Compound (3) showed potent cytotoxic activity against HepG-2 cell line with high selectivity towards hepatocellular carcinoma in vitro (with IC₅₀ = 3.8 μg/mL). Compounds 1 and 2 exhibited significant antioxidant activity and compound 4 showed a significant immune stimulant activity. Compound 1 is isolated for the first time from genus Alcea and this is the first report for its biological investigation.     

Method Development and Quantitative Elemental Analysis of Mentha Longifolia L. Leaves from Saudi Arabia by Total Reflection X-Ray Fluorescence

A method has been developed for the quantitative elemental analysis of Mentha longifolia L. leaves collected from different cities in Saudi Arabia using total reflection X-ray fluorescence. Using a microwave digestion system, 100?mg of each sample was completely digested using 3?mL of nitric acid and 2?mL of hydrogen peroxide. The stabilization of the digested samples on the silicon reflectors was studied using a silicone solution and polyvinyl alcohol. 5?µL of either silicone solution or polyvinyl alcohol (1% m/v) was pipetted and dried on the silicon reflector prior to the deposition of the digested samples. It was recognized that there is some enhancement on the intensity of the peak area with the silicone solution at photon energies less than 11?keV. However, the obtained results confirm the ability of using silicone solution or polyvinyl alcohol (1% m/v) as the stabilizer prior to the deposition of the sample droplet on the quartz reflector. However, the silicone solution was more applicable. Based on the developed method, 15 elements were quantified, namely, P, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Cu, Zn, Br, Rb, Sr, and Ba. Based on the present quantitative analysis results, M. longifolia samples collected from Al-Madina city had the highest concentration of P, Cl, K, Ti, Fe, Ni, and Cu. The lowest concentrations of P, S, Cl, K, Mn, Ni, and Br were found in Taif-Shafa.