Chemistry Journal of Moldova

DOI: dx.doi.org/10.19261/cjm.2008.03(2).01

Graphical Abstract: A relatively simple method for isolation of the mixture of ent-kaur-16-en-19-oic (1) and ent-trachiloban-19-oic (2) acids from dry waste of sunflower processing has been elaborated, and it has been shown that the waste can serve as an accessible source of ent-kauranic and ent-trachilobanic diterpenoids.


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DOI: dx.doi.org/10.19261/cjm.2008.03(2).02

Graphical Abstract: In present work we study two possible single-center units for binuclear iron complex Fe2(bpym)3Cl4 –[Fe(bpym)3]2+ and Fe(bpym)2Cl2. The obtained ground states for both studied systems are singlet states. In the case of Fe(bpym)2Cl2 the lowest excited states were calculated to be 240cm-1 (triplet) and 660cm-1 (quintet) above the ground state and so are placed according to Lande rule. These states could be populated at room temperatures. For [Fe(bpym)3]2+ first excited state was found to be about 6000cm-1 above the ground state and so cannot be populated at normal temperatures.


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DOI: dx.doi.org/10.19261/cjm.2008.03(2).03

Graphical Abstract: The reducing activity and radical scavenging activity of hydrosoluble antioxidants in food compositions from plums during the storage were evaluated. The speeds of changing the reducing activity and radical scavenging activity were different. It was observed that the reducing activity diminished by 63.2% after 62...105 days of storage. The same modification of radical scavenging activity determined in vitro was discovered after 110...254 days of storage. Shelf-life of plum foods was calculated using Weibull distribution. The functional relationship of failure probabilities between the reducing and radical scavenging capacities have been detected (r2= 0. 94-0.98).


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DOI: dx.doi.org/10.19261/cjm.2008.03(2).04

Graphical Abstract: Two novel μ3-oxo-centered carboxylate-bridged triiron complexes [Fe3O(BrCH2COO)6(H2O)3] NO3·2.63H2O (1) and [Fe3O(CH2BrCOO)1.5(CH2ClCOO)4.5(H2O)3]Br0.75Cl0.25 5H2O (2) were synthesized and their structures were characterized by X-ray crystallography. The opportunity of mixed-ligand complex formation in iron(III)-bromoacetic acid system was shown. The first co-ordination sphere of the iron atom in compound 2 includes two different carboxylate anions, CH2BrCOO- and CH2ClCOO- in the capacity of syn-syn- bidentate-bridged ligands, while Br- and Cl- anions being in the ratio 1:1, formulate the external sphere of the complex. The IR spectra, thermic analysis and magnetic properties of complexes were studied.


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DOI: dx.doi.org/10.19261/cjm.2008.03(2).05

Graphical Abstract: New ionic liquids bearing an imidazolium core with a carboxy group have been prepared in an attempt to design new organocatalysts of Biginelli reaction. Trends in the properties of these compounds are discussed. The synthetized compounds represented a novel class of molted salts and may be considered as new organocatalysts for chemical reaction.


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DOI: dx.doi.org/10.19261/cjm.2008.03(2).06

Graphical Abstract: A novel hexanuclear iron-calcium-oxo complex has been synthesized and characterized by different physico-chemical methods and X-ray single crystal structural analysis: [Fe4Ca2O2(μ2-HCCl2COO)10(μ3-HCCl2COO)2(THF)6].The molecular structure shows that there are two types of coordination for COO- anions: bidentate and tridentate.The corresponding variable temperature susceptibility measurement shows that in the complex there exists an antiferromagnetic interaction (|J12| = |J34| = -71.86 cm-1). The iron(III) high spin state (5/2) is proved by Mössbauer spectroscopy. High magnetic EPR measurements of 1 indicates the presence of S=0 ground state with low-lying S=1 excited state centred around g = 2.0054 ±0.0001.


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DOI: dx.doi.org/10.19261/cjm.2008.03(2).07

Graphical Abstract: A new flavonol glycoside, 5,4′-dimethylkaempferol 3-O-β-D-(6′′-α-Lrhamnopyranosyl) -glucopyranoside, together with three known compounds were isolated from the n-butanolic soluble fraction of underground and aerial parts of Linaria vulgaris Mill, collected on the territory of Moldova. The characterisation of these compounds was achieved by various chromatographic and spectroscopic methods (IR, UV, 13C-NMR, 1H-NMR and MS).


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DOI: dx.doi.org/10.19261/cjm.2008.03(2).08

Graphical Abstract: Three phenylethanoid glycosides (1, 2, 3) and one iridoid glycoside (4) were isolated from aerial parts of Veronica chamaedrys L. (Scrophulariaceae) for the first time. On the basis of spectral analysis, the structures of these compounds were determined to be acteoside (3,4-dihydroxy-β-phenylethoxy-O-α-L-rhamnopyranosyl-(1→3)-4-O-caffeoyl-β-D-glucopyranoside) (1), ehrenoside (3,4-dihydroxy-β-phenylethoxy-O-α-L-arabinopyranosyl-(1→2)-α-L-rhamnopyranosyl-(1→3)-4-O-caffeoyl-β-D-glucopyranoside) (2), chamaedroside (3,4-dihydroxy-β-phenylethoxy-O-α-L-rhamnopyranosyl-(1→3)-4-O-caffeoyl-α-L-arabinopyranoside) (3) and aucuboside (4).


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DOI: dx.doi.org/10.19261/cjm.2008.03(2).09

Graphical Abstract: The adsorption process of ammonia ions and ammonium from aqueous solutions on the intact activated carbon obtained from nutshells through activation with phosphoric acid and oxidized with H2O2 and later impregnated with salt containing Co2+, Ag+, Ni2+, Cu2+, has been investigated. The efficiency of ammonia ions and ammonium elimination from various water categories, using both activated carbon (the intact CAN-7 and CAN-7 oxidized with H2O2 and impregnated with Co2+, Ag+, Ni2+, Cu2+ ions) has been demonstrated.


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DOI: dx.doi.org/10.19261/cjm.2008.03(2).10

Graphical Abstract: The method for synthetising new derivatives of the pinonic acid using, at the key step, the reaction of condensation with epichlorohydrin, has been elaborated. It has been shown that, in the presence of catalytic amount of tetrabutylammonium chloride, the reaction is directed towards the formation of etherchlorohydrin, which, later on, is easily transformed into epoxides as well as chloromethyldiketones with good overall yield.


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