Jacek E. Nycz

Contribution to investigation of antimicrobial activity of styrylquinolines.

Series of new ring-substituted styrylquinolines and two oxorhenium complexes were prepared and characterized. The compounds were analyzed using RP-HPLC to determine lipophilicity. Primary in vitro screening of the synthesized compounds was performed against fungal and bacterial strains. Some compounds were active against bacteria at micromolar level and against fungi at submicromolar level. Compounds 5,7-dichloro-2-[2-(2-ethoxyphenyl)vinyl]quinolin-8-ol expressed excellent antifungal activity comparable with or higher than the standard fluconazole as well as antibacterial activity against Staphylococcus strains comparable with or higher than the standards bacitracin, penicillin and ciprofloxacin. The structure-activity relationships are discussed.

Investigating the Activity Spectrum for Ring-Substituted 8-Hydroxyquinolines

In this study, a series of fourteen ring-substituted 8-hydroxyquinoline derivatives were prepared. The synthesis procedures are presented. The compounds were analyzed using RP-HPLC to determine lipophilicity. They were tested for their activity related to inhibition of photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. Primary in vitro screening of the synthesized compounds was also performed against four mycobacterial strains and against eight fungal strains. Several compounds showed biological activity comparable with or higher than the standards isoniazid or fluconazole. For all the compounds, the relationships between the lipophilicity and the chemical structure of the studied compounds are discussed.

REDUCTIVE CLEAVAGE OF THE HALOGEN-PHOSPHORUS, OXYGEN-PHOSPHORUS AND PHOSPHORUS-PHOSPHORUS BONDS WITH ALKALI METALS

Abstract The reduction of phosphorus acid chlorides as well as hypophosphates, pyrophosphates and mixed P(III)-P(V) anhydrides with alkali metals (Li, Na, K)in NH3 liq./THF solution and potassium naphthalenide was investigated. It was found that this type of phosphorus compounds easily undergo reduction: a) >P(O)Cl to >P(O)H; b) >P(O)P(O)< to >P(O)H; c) >P(O)-O-P(O)< to >P(O)OH and >P(O)H; d) >P(O)-O-P< to >P(O)O-and >P. The results of our experiments strongly suggest that the mixed P(III)-P(V) anhydride is reduced by potassium naphthalenide in THF with the cleavage of the P(III) - oxygen bond.

Synthesis, spectroscopy and computational studies of selected hydroxyquinolines and their analogues

Synthetic, spectroscopy and mechanistic aspects of preparation of selected hydroxyquinolines and their analogues or derivatives contained methoxy, fluoro, chloro, carboxylic, carbodithioic and phosphinate or dioxaphosphinane groups were elaborated. The multinuclear NMR and five single crystal X-ray characteristics of the series of quinolines have been determined. The molecular orbitals of the selected hydroxyquinolines have been calculated by density functional theory. The X-ray and NMR studies of 8-[(5,5-dimethyl-2-oxido-1,3,2-dioxaphosphinan-2-yl)oxy]-5,7-dibromo-2-methylquinoline and 8-[(5,5-dimethyl-2-oxido-1,3,2-dioxaphosphinan-2-yl)oxy]-5-fluoro-2-methylquinoline indicate the appearance of anomeric effect.

A solid state and solution NMR study of the tautomerism in hydroxyquinoline carboxylic acids

Some hydroxyquinoline carboxylic acids and their conjugate acids and bases were characterized by 13C and 15N NMR spectroscopy in solution and in the solid state. Differences in 13C and, in particular, 15N chemical shift patterns allow to distinguish between individual tautomers and confirm the presence of zwitterionic species in the solid state. Solution NMR spectra in dimethyl sulfoxide (DMSO) show effects resulting as a consequence of dynamic exchange and suggest the presence of an equilibrium mixture of hydroxyquinoline carboxylic acid and zwitterionic hydroxyquinolinium carboxylate tautomers. Copyright

Identification and derivatization of selected cathinones by spectroscopic studies

In this study we identified three novel hydrochloride salts of cathinones 2-(pyrrolidin-1-yl)-1-(5,6,7,8-tetrahydronaphthalen-2-yl)pentan-1-one (1a) (TH-PVP), 2-(methylamino)-1-(2-methylphenyl)-1-propanone (1b) (2-MMC) and 1-(4-chlorophenyl)-2-(methylamino)propan-1-one (1c) (4-CMC). Their properties have been examined through combinations of GC-MS, IR, NMR, electronic absorption spectroscopy and single crystal X-ray diffraction method. NMR solution spectra showed readily diagnostic H-1 and C-13 signals from methyl, N-methyl and carbonyl groups. Additionally the use of thionation and amination reactions for identification of selected cathinones was presented.

3-[(E)-2-(5,7-Dichloro-8-hydroxy-quinolin-2-yl)vin-yl]-4-hydroxy-phenyl acetate.

The two symmetry independent molecules of the title compound, C19H13Cl2NO4, show similar conformations with the acetyl group twisted strongly relative to the remaining, virtually flat (r.m.s. deviations = 0.0173 and 0.0065 Å), part of the molecule. The hydroxyl groups of the 8-hydroxyquinoline residues are involved in intramolecular O—H⋯N hydrogen bonds, which, in one case, forms a part of a three-center interaction. Intermolecular O—H⋯O hydrogen bonds assemble the molecules into a one-dimensional polymeric structure extended along the a axis. The 4-hydroxyphenyl group of one molecule forms an O—H⋯O hydrogen bond, in which the hydroxyl H atom is disordered, with its inversion center counterpart.

Electrochemistry and spectroelectrochemistry of bioactive hydroxyquinolines: a mechanistic study.

The oxidation mechanism of selected hydroxyquinoline carboxylic acids such as 8-hydroxyquinoline-7-carboxylic acid (1), the two positional isomers 2-methyl-8-hydroxyquinoline-7-carboxylic acid (3) and 2-methyl-5-hydroxyquinoline-6-carboxylic acid (4), as well as other hydroxyquinolines were studied in aprotic environment using cyclic voltammetry, controlled potential electrolysis, in situ UV-vis and IR spectroelectrochemistry, and HPLC-MS/MS techniques. IR spectroelectrochemistry showed that oxidation unexpectedly proceeds together with protonation of the starting compound. We proved that the nitrogen atom in the heterocycle of hydroxyquinolines is protonated during the apparent 0.7 electron oxidation process. This was rationalized by the autodeprotonation reaction by another two starting molecules of hydroxyquinoline, so that the overall oxidation mechanism involves two electrons and three starting molecules. Both the electrochemical and spectroelectrochemical results showed that the oxidation mechanism is not influenced by the presence of the carboxylic group in the chemical structure of hydroxyquinolines, as results from oxidation of 2,7-dimethyl-5-hydroxyquinoline (6). In the presence of a strong proton acceptor such as pyridine, the oxidation ECEC process involves two electrons and two protons per one molecule of the hydroxyquinoline derivative. The electron transfer efficiency of hydroxyquinolines in biosystems may be related to protonation of biocompounds containing nitrogen bases. Molecular orbital calculations support the experimental findings.

Rhenium(I) complexes with phenanthrolines bearing electron-withdrawing Cl and electron-donating CH3 substituents – synthesis, photophysical, thermal, and electrochemical properties with electroluminescence ability

Five rhenium(I) tricarbonyl complexes incorporating 1,10-phenanthroline derivatives with electron-withdrawing Cl and electron-donating CH3 substituents were synthesized, and their photophysical, thermal, and electrochemical properties, with electroluminescence ability were examined. The melting temperature of these complexes was found to decrease from 391 to 281 °C upon adding methyl groups and decreasing the number of chlorine atoms. Compounds bearing methyl substituents could form amorphous molecular materials with glass transition temperatures in the range 118–127 °C. Cyclic voltammetry measurements demonstrated that the complexes are electrochemically active with low energy band gaps in the range 2.24–2.46 eV. All complexes are photoluminescent, form films in the solid state, and blend with poly(9-vinylcarbazole) (PVK) and PVK:(2-(4-tert-butylphenyl)-5-(4-biphenylyl)-1,3,4-oxadiazole) (PBD), emitting light with λem from 560 to 599 nm. They exhibited large Stokes shifts of up to 323 nm in solutions and up to 220 nm as film on a glass substrate. They were tested as guests in organic light-emitting diodes. As hosts, PVK and a binary matrix consisting of PVK with PBD were applied. The ability of the investigated complexes to emit light under an applied voltage was shown.

Reaction of Quinoline-5,8-Diones with Selected Charged Phosphorus Nucleophiles

Abstract The redox reactivity of the two quinoline-5,8-dione derivatives—2-methyl-5,8-dioxo-5,8-dihydroquinoline-7-amine (2a) and N-(2-methyl-5,8-dioxo-5,8-dihydroquinolin-7-yl)acet-amide (2b)—has been demonstrated by their reaction with negatively charged three-coordinated phosphorus nucleophiles, such as R2P-YM (1a–d, Y = O or lone pair; R = Ph, tBu, OCH2CMe2CH2O, or EtO; M = Li or Na). 1a–d participated in single-electron transfer (SET) to 2a and 2b, generating the radical anions 3 and 4, respectively, together with short-lived phosphorus-centered radical intermediates of type R2P(= Y)· (5). The radicals 5 dimerize to give R2P(Y)–(Y)PR2 (6). Both 3 and 4 are remarkably persistent with half-lives of more than 1 month in THF (tetrahydrofuran) at 300 K. GRAPHICAL ABSTRACT