Elżbieta Wyrzykiewicz

Mass spectrometry of bis-quinolizidine alkaloids: 2- and 17-alkyl-substituted derivatives of sparteine and lupanine

The mass spectral fragmentations of 2-methylsparteine (1), 2, 17-dimethylsparteine (2), 2-methyl-17-isopropylsparteine (3), 2-methyl-17-oxosparteine (4), 2-oxo-17-methylsparteine (17-methyllupanine) (5) and 2-oxo-17-isopropylsparteine (17-isopropyllupanine) (6) were investigated. Fragmentation pathways, whose identification was assisted by accurate mass measurements and a correlation between the abundances of the M(+.) and selected fragment ions of the investigated compounds, are discussed. The data obtained create the basis for distinguishing the structural isomers and metamers.

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.

Thio Analogues of Pyrimidine Bases: Syntheses and Spectral Study of New Potentially Biologically Active 2,4-Di-Ortho-(Meta- and Para-)Bromo- (Chloro and Nitro)-Benzylthio-5-Bromouracils (and 6-Methyluracils)

Eighteen new 2,4-di-ortho- (meta- and para-) bromo-(chloro- and nitro-)benzylthio-5-bromouracils (and 6-methyluracils) have been prepared. The structures of these compounds were confirmed by spectral (IR, UV/vis, 1H NMR) and elemental analyses. Estimation of pharmacotherapeutic potential has been made for synthesized compounds on the basis of prediction of activity spectra for substances (PASS).

Synthesis and antimicrobial activity of (E)-acetoxystilbenes and α,α′-dibromoacetoxybibenzyls

Abstract The synthesis of 13 new ( E )-acetoxystilbenes and α,α′-dibromoacetoxybibenzyls and their antimicrobial activity are reported. The results of microbiological screening of 17 ( E )-stilbenols and ( E )-acetoxystilbenes, unknown in the literature, have also been discussed. In particular, coumpounds 1c , 1g , 2a , 3a , 3b , 4a , 6a , 6b showed good antibacterial activity against Staphylococcus aureus and 1c also against Bacillus subtilis .

Mass Spectrometry of Bis-quinolizidine Alkaloids: Differentiation of Stereoisomers and Metamers Using ESI and FAB Mass Spectrometry

ABSTRACT The ESI and FAB mass spectral fragmentations of seven bis-quinolizidine alkaloids were investigated. Fragmentation pathways, elucidation of which was assisted by FAB/CID mass spectra measurements, are discussed. The data create the basis for distinguishing stereoisomers and metamers.

Thio Analogs of Pyrimidine Bases: Syntheses, EIMS and 13 C NMR Study of New Ortho -( Meta - and Para -) Substituted Derivatives of 2-benzylthio-5-bromo-6-methyluracils

Nine new ortho -( meta - and para -) substituted derivatives of 2-benzylthio-5-bromo-6-methyluracils have been prepared. EI induced mass spectral fragmentation of these compounds was investigated. Fragmentation pathways are proposed on the basis of accurate mass and metastable transitions measurements. The correlation between the intensities of the M +. and the selected fragment ions of these compounds is discussed. 13 C NMR spectra of these compounds were assigned. The data derived from EIMS and 13 C NMR spectra can be used to differentiate the isomers.

Synthesis and Conformational Assignment of N-(E)-Stilbenyloxymethylenecarbonyl-Substituted Hydrazones of Acetone and o-(m- and p-) Chloro- (nitro-) benzaldehydes by Means of and NMR Spectroscopy

Eighteen new N-(E)-stilbenyloxyalkylcarbonyl-substituted hydrazones of ortho- (meta- and para-) chloro- (nitro-) benzaldehydes 1–18 and two analogous hydrazones of acetone 19-20 were prepared. The stereochemical behavior of 1–18 in dimethyl-d6 sulfoxide solution has been studied by NMR and NMR techniques, using spectral data of 19 and 20 as supporting material. The E-geometrical isomers and cis-/trans-amide conformers have been found for these hydrazones. Energy barriers of isomers are reported.

Mass spectrometry of metal complexes of bis-quinolizidine alkaloids: electron ionization and fast atom bombardment mass spectral study of copper(II) (–)-sparteine and (–)-α-isosparteine complexes

The electron ionization (EI) and fast atom bombardment (FAB) mass spectral fragmentations of ten copper(II) dichloride (dibromide, diformate, diacetate and dithiocyanate) complexes of (–)-sparteine and (–)-α-isosparteine were investigated. Fragmentation pathways, elucidation of which was assisted by accurate mass measurements and metastable transitions (EI-MS), as well as FAB/collision-induced dissociation (CID) mass spectral measurements are discussed. The data obtained create the basis for the differentiation of the ligand (sparteine or α-isosparteine) in the investigated complexes. The comparison of the results with those obtained previously for corresponding zinc(II) complexes forms the basis for the differentiation of metals in these compounds. The results show that both EI-MS and FAB-MS are very useful tools for the differentiation of ligands, as well as metals in the series of Zn(II) and Cu(II) dichloride (dibromide, diacetate, diformate, dithioacetate) complexes of (–)-sparteine and (–)-α-isosparteine.

Electron ionization and fast atom bombardment mass spectral study for differentiation of ligand of zinc(II) (–)-sparteine and (–)-α-isosparteine complexes

The (–)-sparteine bis-quinolizidine alkaloid produced by lupine species has generated much interest due to its pharmacological properties, and its application in asymmetric synthesis. The basic bis-quinolizidine system of (–)sparteine consists of four rings, two of which (A/B) form a double-chair system of trans-quinolizidine, which is relatively resistant (for thermodynamic reasons) to conformationalconfigurational changes. The second system of rings (C/D) is much more susceptible to inversion at the N16 nitrogen atom and it can occur in either the trans boat-chair or the cis double-chair conformation. According to Haasnoot, sparteine adopts exclusively the C-boat conformer. Theoretical calculations have confirmed that the free base of sparteine has one predominant conformer with a chair-

Syntheses, EIMS, 1H NMR, and 13C NMR Study of 2-Mono, 1,2-Di, and 2,4-Di Substituted Derivatives of 2-Thiocytosine

Seventeen new S-ortho-(meta- and para-) bromo-(chloro- and nitro-) benzylsubstituted 2-thiocytosines as well as S and N-1 (S- and N-4) ortho-(meta- and para-) bromo-(chloro- and nitro-) benzyl disubstituted hydrohalides of 2-thiocytosines have been prepared. The 1H and 13C NMR spectra of these compounds have been assigned unambiguously using a two-dimensional 13C, 1H-one-bond correlation (HETCOR) ( 1–9 ) and a two-dimensional 13C, 1H -Long Range correlation (HMBC) ( 10–18 ) spectra. Electron-impact (EI)-induced mass spectral fragmentation of S-benzyl substituted derivatives of 2-thiocytosine has been investigated. The data obtained make the basis for distinguishing isomers.