A5036984210- Chemical Synthesis and Analysis
- Natural product bioactivities and synthesis
- DNA and Nucleic Acid Chemistry
- Carbohydrate Chemistry and Synthesis
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Sesquiterpenes and Asteraceae Studies
- Molecular spectroscopy and chirality
- Plant biochemistry and biosynthesis
- Analytical Chemistry and Chromatography
- Organophosphorus compounds synthesis
- Steroid Chemistry and Biochemistry
- Advanced biosensing and bioanalysis techniques
- HIV/AIDS drug development and treatment
- Biochemical and Molecular Research
- Organic Chemistry Cycloaddition Reactions
- Phytochemistry and Biological Activities
- Synthesis and Characterization of Heterocyclic Compounds
- Axial and Atropisomeric Chirality Synthesis
- Synthesis of Organic Compounds
- Click Chemistry and Applications
- Plant Toxicity and Pharmacological Properties
- Synthesis and Reactivity of Sulfur-Containing Compounds
- Biological Activity of Diterpenoids and Biflavonoids
- Chemical Reaction Mechanisms
Czech Academy of Sciences, Institute of Organic Chemistry and Biochemistry
2015-2024
Czech Academy of Sciences
2010-2021
Charles University
1994-2009
University of Michigan
2009
Czech Academy of Sciences, Institute of Biotechnology
2009
Consejo Nacional de Investigaciones Científicas y Técnicas
2009
University of Buenos Aires
2009
Czech Academy of Sciences, Institute of Biophysics
2009
Czech Academy of Sciences, Institute of Physics
2002-2008
University of Illinois Urbana-Champaign
2006
Despite the simplicity of molecule, site single deprotonation p-hydroxybenzoic acid upon electrospray ionization (ESI) has recently formed a subject debate in this journal. By means NMR experiments solution and gas-phase studies employing ion-mobility mass spectrometry (IM-MS), apparent controversy is resolved. It shown that irrespective solvent carboxylate tautomer preferred solution, while opposite holds true for isolated ions gas phase. The distribution sampled phase very much depends on...
Chimerical pyrene-based dibenzo[7]helicene rac-1 and 2H-pyran[7]helicene (M,R,R)-(-)-2, in which two pyrene subunits are fused to the [7]helicene/[7]heterohelicene scaffold, were synthesised by means of Ni(0) - or Co(I) -mediated [2+2+2] cycloisomerisation dipyrenyl-acetylene-derived triynes. Pyrene-based 1 was obtained enantioenriched form enantioselective under /QUINAP catalysis (57 % ee) enantiopure racemate resolution liquid chromatography on a chiral column. 1,3-Allylic-type...
Oxahelicene NHC ligands were used in Ni-catalysed enantioselective cycloisomerisation of alkynes to obtain helicenes up 86% ee.
Abstract A series of oxahelicenes composed ortho / meta ‐annulated benzene/pyridine and 2 H ‐pyran rings were synthesized on the basis cobalt(I)‐mediated (or rhodium(I)‐ or nickel(0)‐mediated) double, triple, quadruple [2+2+2] cycloisomerization branched aromatic hexa‐, nona‐, dodecaynes, thus allowing construction 6, 9, 12 in a single operation. The use flow reactor was found to be beneficial for multicyclization reactions. stereogenic centers present some oligoynes steered helical folding...
Cyclic dinucleotides are second messengers in the cyclic GMP–AMP synthase (cGAS)–stimulator of interferon genes (STING) pathway, which plays an important role recognizing tumor cells and viral or bacterial infections. They bind to STING adaptor protein trigger expression cytokines via TANK binding kinase 1 (TBK1)/interferon regulatory factor 3 (IRF3) inhibitor nuclear factor-κB (IκB) (IKK)/nuclear (NFκB) signaling cascades. In this work, we describe enzymatic preparation 2′–5′,3′–5′-cyclic...
In this paper we present a simple and efficient two-step procedure for the preparation of triformylmethane from bromoacetic acid dimethylformamide, synthesis some derivatives preparative importance, evidence an intramolecular hydrogen bond in triformylmethane, based on its 1H-NMR spectra measured deuterochloroform presence trichloroacetyl isocyanate, comments recent erroneous statements1 concerning IR triformylmethane.
Three novel structurally related pentadecapeptides, named lasioglossins, were isolated from the venom of eusocial bee Lasioglossum laticeps. Their primary sequences established as H-Val-Asn-Trp-Lys-Lys-Val-Leu-Gly-Lys-Ile-Ile-Lys-Val-Ala-Lys-NH(2) (LL-I), H-Val-Asn-Trp-Lys-Lys-Ile-Leu-Gly-Lys-Ile-Ile-Lys-Val-Ala-Lys-NH(2) (LL-II) and H-Val-Asn-Trp-Lys-Lys-Ile-Leu-Gly-Lys-Ile-Ile-Lys-Val-Val-Lys-NH(2) (LL-III). These lasioglossins exhibited potent antimicrobial activity against both...
The application possibilities of the in situ reactions trichloroacetyl isocyanate (TAI method) to structural assignment alcohols by means 1 H NMR spectroscopy are critically evaluated. TAI acylations various solvents demonstrated and reactivity functional groups, potentially complicating or extending applications TAI, is discussed. In addition their use analysis such also can serve as model experiments for preparative purposes.
Abstract Chemically modified nucleoside triphosphates (NTPs) are widely exploited as unnatural metabolites in chemical biology and medicinal chemistry. Because anionic NTPs do not permeate cell membranes, their corresponding neutral precursors employed cell‐based assays. These become active after enzymatic conversion, which often proceeds insufficiently. Here we show that metabolically‐active can be directly transported into eukaryotic cells bacteria by the action of designed synthetic...
Antimutagenic activity-guided fractionation of an extract prepared from the thorns Gleditsia sinensis LAM. led to isolation one triterpenoid and four steroids, which were identified as D:C-friedours-7-en-3-one (1), stigmast-4-ene-3,6-dione (2), stigmastane-3,6-dione (3), stigmasterol (4), β-sitosterol (5). Triterpenoid 1 was found for first time in a natural source steroids 2—5 isolated this plant. Stigmasterol most active antimutagen, showing 51.2% 64.2% reduction induction factor against...
[reaction: see text] A new approach to nonracemic [7]helicene-like molecules has been developed. Stereoselective Co(I)-mediated [2 + 2 2] cycloisomerization of aromatic triynes containing an asymmetric carbon atom produces scaffolds in diastereomeric ratios up 100:0. This central-to-helical chirality transfer can be controlled by the absolute configuration at center and presence substituents.
A matter of concentration: Cyclic pseudorotaxanes are formed by the addition copper(I) ions to a ligand consisting ring containing chelating unit and, appended ring, rigid fragment another unit. The tetramer is as major product in concentrated solution, and analogous trimer prevails more dilute solution; both species connected through concentration-dependent slow equilibrium. Supporting information for this article available on WWW under...
β-Cyclodextrin–flavin conjugates are highly efficient catalysts for the sulfoxidation of methyl phenyl sulfides with hydrogen peroxide in neat aqueous media operating at loadings down to 0.2 mol% and allowing enantioselectivities up 80% ee.
Reaction of phosphoroorganic synthons with 8-azaadenine, 8-aza-2,6-diaminopurine, and 8-azaguanine using cesium carbonate yielded regioisomeric 8-azapurine N7-, N8-, N9-(2-(phosphonomethoxy)alkyl) derivatives. This reaction followed by deprotection afforded isomeric 2-(phosphonomethoxy)ethyl (PME), (S)-(3-hydroxy-2-(phosphonomethoxy)propyl) [(S)-HPMP], (S)-(3-fluoro-2-(phosphonomethoxy)propyl) [(S)-FPMP], (S)-(2-(phosphonomethoxy)propyl) [(S)-PMP], (R)-(2-(phosphonomethoxy)propyl) [(R)-PMP]...
Abstract The assignment of some 1 H and 13 C NMR chemical shifts apigenin have been uncertain even contradictory. A reinvestigation with recent techniques has led to a new set parameters confirmed the accepted data.
Abstract Carbon‐13 NMR spectra are reported for 63 substituted benzonitriles in deuteriochloroform or its mixture with dimethyl sulphoxide‐ d 6 . The substituent‐induced chemical shifts (SCS) of the CN carbon correlate well dual substituent parameters (DSP) para series but poorly meta series, whichever used. DSP treatment was found to be inferior principal component analysis (PCA), using as a probe 29 sets literature data on α,β‐unsaturated benzene derivatives. Whereas one is sufficient...
Interpretation of the Raman optical activity (ROA) peptides is difficult because molecular flexibility and interaction with solvent. Typically, simulations experiments are compared in terms a qualitative agreement between spectra. However, on series Pro-Gly, Gly-Pro, Pro-Ala, Ala-Pro dipeptides more precise conformer ratios could be obtained aid density functional computations numerical decomposition spectral shapes. All observed transitions were assigned, computed transition frequencies...
Four structurally different alloxazine-cyclodextrin conjugates were prepared and tested as catalysts for the enantioselective oxidation of prochiral sulfides to sulfoxides by hydrogen peroxide in aqueous solutions. The alloxazinium unit was appended primary face α- β-cyclodextrins via a linker with variable length. A series used substrates: n-alkyl methyl (n-alkyl = hexyl, octyl, decyl, dodecyl), cyclohexyl sulfide, tert-butyl benzyl sulfide thioanisol. α-Cyclodextrin conjugate having...