Zdzisława Nowakowska

Antimicrobial activity of some N-alkyl substituted of (E)-4-azachalconium and (E)-3′-hydroxy-4-azachalconium bromides

Twelve new N-substituted (E)-azachalconium bromides were synthesized and tested for antimicrobial and antifungal activities. Compounds 5c, 5d and 5h-5l showed very good antimicrobial activity against Staphylococcus aureus, Enterococcusfaecalis as well as Bacillus subtilis and 5h-5j showed moderate activity against Escherichia coli. In particular, (E)-N-dodecyl-4-azachalconium bromide (5i) and (E)-N-tetradecyl-4-azachalconium bromide (5j) showed the most intensive activity against all tested microorganisms.

Thiol-functionalized anthraquinones: mass spectrometry and electrochemical studies

In this work, the synthesis of various thiol-functionalized anthraquinone compounds is presented. The studied compounds were characterized by mass spectrometry and the main fragmentation pathways are discussed. The compounds studied formed stable self-assembled monolayers (SAMs) in the gold surface. The parameters for the reduction processes in the gold surface of the studied new anthraquinones were determined by cyclic voltamperometry tests.Graphical abstract

Structural Assignment of Stilbenethiols and Chalconethiols and Differentiation of Their Isomeric Derivatives by Means of 1H‐ and 13C‐NMR Spectroscopy

Abstract The 1H‐ and 13C‐NMR spectra of some substituted stilbenes and chalcones were assigned unambiguously on the basis of a combination of homo‐ (COSY) and heteronuclear (HETCOR) two‐dimensional methods, the chemical shifts, as well as spin‐coupling constants. The Aik empirical parameters of the –O–C(S)–N(CH3)2, –S–C(O)–N(CH3)2, and –SH group were calculated to help predict the chemical shifts of substituted stilbenes, 4′‐nitrostilbenes, and chalcones. The 1H‐ and 13C‐NMR spectra have been shown to be able to differentiate between the isomers of O‐stilbenyl (4, 5) and S‐stilbenyl N,N‐dimethylthiocarbamates (7, 8) as well as O‐chalconyl (6) and S‐chalconyl N,N‐dimethylthiocarbamates (9).

1H and13C NMR chemical shift assignment of someN-bromoalkyl-(E)-4-azachalcone bromides

The 1H and 13C NMR spectra of some N‐bromoalkyl derivatives of (E)‐4‐azachalcone were assigned unambiguously using a combination of homonuclear (COSY) and heteronuclear (HETCOR) spectra, the chemical shifts and spin‐coupling constants. Copyright

Electron impact mass spectral study of halogenated N-acetyl- and N-propionylcytisines.

(-)-Cytisine and its derivatives, characterised by high affinity to neuronal nicotinic acetylcholine receptors with specificity for the α4β2 subtype, have been shown to be important probes in central nervous system (CNS) research. Electron impact mass spectral (EI-MS) fragmentations of halogenated derivatives of N-acetylcytisine and N-propionylcytisine have been investigated. Detailed fragmentation pathways have been identified for all significant ions including a few characteristic fragment ions. The principal mass spectral fragmentation routes of iodine and bromine compounds have been determined on the basis of low (EI), high resolution (HRD) and B(2)/E linked scan mass spectra as well as linked scans at constant B/E.

Structural Characterization and Differentiation of Isomeric ω-Bromoalkoxy Derivatives of (E)-Chalcone by Means of Mass Spectrometry

Mass spectrometry with electron ionization and electrospray ionization have been applied to characterize and differentiate the isomeric ortho-, meta- or para-(E)-bromoalkyloxychalcones 1–15. The difference in the values of μ1–μ5 (i.e. the ratio of abundances of the selected fragment ions to those of the molecular ions) in the series of isomeric chalcones studied and the so-called “in-source” fragmentation induced by increasing cone voltage have been found to be important and reliable indicators differentiating the isomers studied.

Letter: Electron ionization-induced fragmentation of new thiochalcone derivatives

Electron ionization mass spectral fragmentation of new (E)-4-chalconylothioalkyl-substituted derivatives of piperidinie, 4-methyl-piperidine, morpholine and piperazine as well as (E)-4-bromoalkylthiochalcones, being substrates of the former compounds, have been studied. Fragmentation pathways have been proposed on the basis of the accurate mass and metastable transition measurements.

The Conversion of Stilbenols to Stilbenethiols via N,N-Dimethylthiocarbamates

A series of O-stilbenyl N,N-dimethylthiocarbamates has been prepared by the reaction of N,N-dimethylthiocarbamoyl chloride with stilbenols in the presence of DABCO and DMF. The thermal rearrangement of O-stilbenyl N,N-dimethylthiocarbamates into S-stilbenyl analogues has also been studied. The S-stilbenyl N,N-dimethylthiocarbamates obtained have been converted into the corresponding stilbenethiols. Electron ionization mass spectral fragmentation of these compounds has been studied. Fragmentation pathways have been proposed on the basis of the accurate mass and metastable transition measurements.

(E)‐4‐Alkoxycarbonylalkylthiochalcones: differentiation of isomeric derivatives by electron ionization mass spectrometry

The principal fragmentation pathways of the molecular ions of 18 new (E)-4-alkoxycarbonylalkylthiochalcones have been investigated. It has been shown that the data derived from electron ionization mass spectra (the relative abundance of the fragment ions and values of coefficients micro) can be used to differentiate the isomers. The fragmentation rules deduced here could help in the characterization of other chalcones of these types.

Reactions of (E)-4-Stilbenethiole with Dibromoalkanes

New substituted stilbenes have been prepared by reactions of (E)-4-stilbenethiole with dibromoalkanes. 1H and 13C NMR spectra of new compounds have been assigned unambiguously on the basis of a combination of homo- (1H−1H COSY) and heteronuclear (1 H−13C COSY-HETCOR) two-dimensional methods, chemical shifts, and spin-coupling constants.