Vietnam Journal of Chemistry

Lanthanide amino acid chelates are known to play an important role in many biological processes and prove the higher bioactivity compared to their inorganic compounds or complexes, so that there is a growing need for methods of characterizing these chelates. Raman as well as infrared (IR) spectroscopy can be used to identify as well as characterize the coordination of metal with ligand. However, the combination of both spectroscopic techniques can give a better evaluation of their molecule structures. The chelate of Ytterbium with L-isoleucine (essential amino acid) as ligand, were synthesized in ethanol-water solution and analyzed by spectroscopic means (Raman, FTIR). The comparative analysis of the IR and Raman spectra for the ligand and the complexes indicate the coordination of Ytterbium ion with the carboxylic oxygen atom and the nitrogen atom of the amino group to form chelate. Key words: Ytterbium, L-isoleucine, chelate, coordination, vibrational spectra, FT Raman, FTIR.

A series of nine hydrazones has been synthesized by condensation of 2-methoxy-4-(3-methyl-2-oxide-1,2,5-oxadiazol-4-yl)phenoxyacetylhydrazine with aromatic aldehydes. The structure of  compounds has been confirmed by IR, 1H NMR and  13C NMR.

Copper nanoparticles were prepared by hydrogen reduction by electrolysis of water. The formation, structure and morphology of products were characterized by X-ray diffraction analysis (XRD), Scanning Electron Microscope (SEM) and the specific surface area (BET) was determined by N2 physisorption Brunauer - Emmitt - Teller (BET) method. The results showed that copper particles are a simple phase and the size about 40-70 nm, the BET-surface area as 15.85 m2/g. The data showed that copper nanoparticles increased germination rate of maize at normal condition. Keywords: Copper nanoparticles, reverting method.

The ethyl acetate extract of the barks of Ficus religiosa L. showed moderate antioxidant activity in DPPH radical scavenging assay with SC50 value is 23.1 μg/ml. Five compounds including vanillic acid (1), 4-hydroxybenzoic acid (2), protocatechuic acid (3), gallic acid (4) and shikimic acid (5) were isolated from the barks of this plant. Their structures were identified by Mass and NMR spectra.

Three compounds were isolated from the n-hexane and ethyl acetate extracts of Artocarpus lakoocha collected in Son La province. Their structures were elucidated as friedelane-3-one, stigmast-4-ene-3-one and 1-tricosanoyl-glycerol by analysis of MS, NMR spectra and comparison with the published data.

Contaminated solid waste at munition factories is a serious problem since it contains 2,4,6- trinitrotoluene (TNT), a nitroaromatic compound toxic to human health as well as to aquatic and terrestrial life. Our objective was to determine if zero-valent iron (Fe°) associated with H2O2 could be used to degrade 2,4,6- trinitrotoluene (TNT) in slurries of the solid waste and water. The results show that sequential treatments of a TNT-contaminated solid waste (277 mg TNT kg-1) with Fe° (1% w/w) within 6 hours followed by H2O2 (0.5% v/v) within 8 hours completely destroyed TNT and its highly toxic anilinic intermediates. The optimal performance of Fe0 powder was obtained when the reagent was added in four increments rather than in a single dose. Our observations also indicate that ion Cl- improved the performance of the reduction of TNT by Fe°.

Starting from menthol, 14 compounds containing menthane skeleton have been synthesized; 12 of them are 1,2,4-triazole derivatives. Their structure have been determined by UV, IR, 1D NMR, 2D NMR and MS spectral data. Some synthesized compounds were tested for bactericidal and fungicidal activities.

Starting from salicylic acid, 2-hydroxy-5-iodobenzohydrazide and eight N-substituted hydrazides have been synthesized. The structure of  the N-substituted hydrazides  have been determined by IR and 1H-NMR spectra.

Abstract A series of chalcone analogues were synthesized using Claisen‐Schmidt condensation and assayed for in vitro inhibitory activity against α‐glucosidase. The synthesis involved in solvent‐free reaction conditions including NaOH‐catalyzed grinding or microwave irradiation in the presence of a clay‐based catalyst. Hydroxychalcones and 2′‐hydroxychalcones were not isolated when using grinding method, while the microwave‐assisted, clay‐catalyzed synthesis gave these desired products. In addition, flavanones, cyclization products from 2′‐hydroxychalcones were formed in both methods. Flavanones 3g and 3s were the most active toward α‐glucosidase. Compound 3g exhibited an effect (IC50 = 10.4±0.2 μM) close to genistein (IC50 = 7.8±0.3 μM), a known α‐glucosidase inhibitor. Structure‐activity relationship analysis indicated that the 4‐hydroxy substituted motif in ring B of chalcones seems to be an important factor on the α‐glucosidase inhibitory activity. Furthermore, the 3,4‐difluorinated chalcones also exhibited activities as compared to mono‐fluorinated derivatives, suggesting that the more fluorination in ring B may be crucial for the inhibitory activity.