Chemistry Journal of Moldova

DOI: dx.doi.org/10.19261/cjm.2015.10(1).08

Graphical Abstract:  The paper relates on the discovered bioactivity of the iridoid glycosides extract (IGE) from Linaria genistifolia (L.) Mill, namely its stimulating influence on the resistance of the winter wheat Odesschi 51 plant to the caused by the F. oxysporum and H. avenae pathogenic fungi root rot. 1H and 13C NMR characteristics of 5-O-allosylantirrinoside in Py-d5 are for the first time presented. Structures of two conformers of the IGE main component, 5-O-allosylantirrinoside in D2O and Py-d5 solutions are proposed, based on the experimental NMR evidence and molecular modeling studies.

DOI: dx.doi.org/10.19261/cjm.2015.10(1).09

Graphical Abstract:  Described synthesis of 5-bromo substituted oxindoles linkages in spirocyclic butenolides exhibit relatively dependence of the structure-reactivity relationships of N-substituted isatines, dimethyl acetylenedicarboxylate and triphenylphoshine. The study of the stereochemistry of the atom C(2) of the spiro compounds was also unambiguously confirmed by single crystal X-ray analysis. 

DOI: dx.doi.org/10.19261/cjm.2015.10(1).10

Graphical Abstract:  In this study, the protonation states of ionizable groups of human lactoferrin in various conformations were investigated theoretically, at physiological pH (7.365). These calculations show that the transition of the protein from a conformation to another one is accompanied by changes in the protonation state of specific amino acid residues. 

DOI: dx.doi.org/10.19261/cjm.2015.10(1).11

Graphical Abstract:  The surface chemistry of the commercial active carbon AG-5 has been modified by oxidation with concentrated nitric acid. The structural changes caused by oxidative treatment were estimated on the basis of nitrogen adsorption-desorption isotherms and thermal analysis. Boehm titration method and infrared spectral analysis have been used in order to evaluate surface chemistry characteristics of active carbon samples.

DOI: dx.doi.org/10.19261/cjm.2015.10(1).12

Graphical Abstract:  57Fe Mӧssbauer spectra were recorded for 1'-terpyridine ferrocenecarboxylic acid and [bis(1'-terpyridine ferrocenecarboxylic acid) Fe(II)]2+ in the temperature range 7 – 293 K. The temperature dependence of the Quadrupole Splitting, Isomer Shift and Debye-Waller factor are discussed. The Debye temperature, θ_D, for the iron nuclei in the investigated compounds was determined.

DOI: dx.doi.org/10.19261/cjm.2015.10(1).13

Graphical Abstract:  The preferred mechanism of the reaction of dihydroxyfumaric acid and its dimethyl ether with the free stable radical 1,1-diphenyl-2-picrylhydrazyl (DPPH*) was revealed by means of Density Functional Theory (DFT) calculations. The proposed mechanism has an ionic character and includes the formation of charge-transfer complexes as the main stage. It is also shown that the lower antioxidant activity of dimethyl ether of dihydroxyfumaric acid is caused by both its lower acidity (as compared with its precursor acid) and formation of more stable intermediates during its reaction with DPPH*. Our results allow one to rationalize the available experimental data.

DOI: dx.doi.org/10.19261/cjm.2015.10(1).14

Graphical Abstract: This paper reports on the preparation of activated carbon from walnut shell. Orthogonal array experimental design method was used to optimize the preparation of activated carbon with phosphoric acid by using microwave treatment. The optimization parameters were: microwave power, activation time, phosphoric acid concentration and particle sizes of nut shells. Thermal analysis of the intact and impregnated with phosphoric acid walnut shells was used for the simulation of activation process. Activated carbon with the optimal parameters was obtained, being characterized by gas adsorption method and scanning electron microscopy.