We presented an efficient synthesis and application of a new member of the ansa-ruthenium catalysts for asymmetric transfer hydrogenation which follows the increasingly popular trend towards structurally-rigid Ru(II) catalysts for ketone reduction. It exhibited excellent performance against a challenging class of substrates such as 1-naphthyl ketones displaying high enantioselectivity and activity. In fact, the catalyst with an substrate-to-catalyst ratio of 1000 in the presence of HCO2H-Et3N (5:2) at 40-60 °C, afforded alpha-(1-naphthyl)ethanols with up to )99.9% enentiomeric excesses and complete conversions within 6-20 h. These results are very valuable in metal-catalyzed synthesis and potentially useful for the preparation of chiral pharmaceuticals or chiral building blocks in general.
COBISS.SI-ID: 36628229
Synthetic probes for recognition of double stranded DNA are useful for the recognition and regulation of genes. To this purpose a series of 2'-amino-α-L-LNA modified nucleotides was developed. A pyrene moiety, which intercalates between base pairs of double stranded DNA, is attached to the LNA bridge. Oligonucleotides with such modifications specifically bind to the target DNA and form thermally stable hybrids. Complexes with modified nucleotides have been characterized using fluorescence and NMR spectroscopy and molecular modeling.
COBISS.SI-ID: 5386522
In this paper chemical composition of the essential oil (analysed by GC and GC-MS), the content of phenolic compounds (analysed by HPLC), quantity of total phenols and total flavonoids (analysed by UV/Vis spectrophotometer), antioxidant and antimicrobial activities of ethanolic extracts were investigated in Teucrium arduini L.. The oil was characterized by a high concentration of sesquiterpene hydrocarbons. Three phenolic compounds (quercetin, ferulic acid and rosmarinic acid) were identified and quantified using HPLC. The ethanol extracts prepared from the leaf of T. arduini showed broad spectrum of antimicrobial activity on Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and Aspergillus brasiliensis, whilst Microsporum gypseum was resistant at investigated concentrations.
COBISS.SI-ID: 620940
25 nt guanine-rich vascular endothelial growth factor aptamer was studied with CD, UV and NMR spectroscopy. While unmodified aptamer folds into several G-quadruplex structures in the presence of potassium ions, modifications with locked and unlocked nucleotides lead to the stabilization of a single parallel structure with three G-quartets. Unusual features of the structure include five consecutive guanine residues that are all included in the G-quadruplex core, and a new type of D-shaped loop that brings isolated guanine residue in the G-quartet. The edgewise and propeller loops connect the remaining two G-rich tracts. 5' and 3' overhangs are well structured and were shown to importantly contribute to the formation of structurally pre-organized intermediates and stabilizations of the single G-quadruplex structure.
COBISS.SI-ID: 5373466
We have developed a 4D C,C-edited NOESY experiment where we used the carbon and proton dimensions. The inclusion of the aromatic 13C dimension allowed us to separate H1'-H8 and H1'-H6 correlation signals from more intensive H5-H6 signals on the basis of separation of C5 and C1' regions. The degeneracy of H1 'and H5 chemical shifts limits the use of aromatic 3D NOESY-HSQC experiment for sequential assignment, which requires to record complementary ribose 3D NOESY-HSQC experiment. In communication, we proposed to replace the non-optimal approach with the use of a selective 4D C,C-edited NOESY experiment. 13C dimension allowed us to reduce the overlapping spectra in the case of large RNAs or RNAs with poor dispersion of chemical shifts. 4D C,C-NOESY experiment was tested on the isotope 13C,15N-labeled 34-nt hairpin RNA consisting of two A-RNA stems, one adenine bulge, an asymmetric internal loop and a GAAA terminal loop.
COBISS.SI-ID: 5307930