Catalysis based on nanoparticles is very rapidly evolving. We reported here a method for the generation and entrapment of rhodium nanoparticles in simple solid ammonium salts, starting from quaternary ammonium salts, rhodium compounds, hydrogen and CO2. Nanoparticles thus obtained were used as selective catalysts for the hydrogenation of simple substrates and also for more complex, that cannot be easily hydrogenated. Prof. Leitner received for present results Wöhler Prize for 2009 (See: Angew. Chem. Int. Ed., 2009, 48, 6587).
COBISS.SI-ID: 30100997
In the field of unsaturated cyclic amino acid derivatives we investigated the double Diels-Alder cycloaddition reaction of 2H-pyran-2-ones with N-substituted maleimides or maleic anhydride yielding bicyclo[2.2.2]octene derivatives. We observed an unusual effect of the size of the ring fused to 2H-pyran-2-ones on the exo/endo selectivity of this cycloaddition reaction. With subtle variations of starting compounds and reaction conditions (conventional heating in solvents and microwave-assisted reactions in solvents or as neat reactions) exclusively exo,exo or exo,endo products can be prepared.
COBISS.SI-ID: 30678277
In collaboration with French partners we investigated selective transformations of organic molecules catalyzed by transition metals. It was demonstrated that (p-cymene)ruthenium diacetate in the presence of K2CO3 acts as an excellent catalyst for ortho C-H bond functionalization of 2-pyridylbenzene. This work, performed at the postdoctoral position in France, initiated our further fruitful cooperation with Professors Dixneuf and Doucet (See also: F. Požgan, H. Doucet, et al., Green Chem. 2009, 11, 425; Green Chem. 2009, 11, 1832; J. Org. Chem. 2009, 74, 1179.).
COBISS.SI-ID: 30712837
An efficient synthesis of pyrazol-3-ones involves intramolecular amination of the appropriate diazenes and starts from easily available propenoic acids. The latter were prepared by the Perkin reaction of arylacetic acids with aromatic aldehydes and then transformed into the corresponding hydrazides. Oxidation of hydrazides gave the diazenes that cyclized on treatment with ZrCl4. The methoxycarbonyl protection of N-1 of the pyrazolone was removed under mild reaction conditions. This methodology opens up new entries to a number of biologically active pyrazolo-fused compounds.
COBISS.SI-ID: 30775045
Investigating new molecular probes for detecting changes in the central nervous system (CNS) we compared our own results with the results of other research groups on in vivo methods for assessment of disease progression. We compared different molecular probes used with Positron Emission Tomography (PET) to assess the formation of protein aggregates in the CNS of Alzheimer’s disease patients.
COBISS.SI-ID: 30279685