Pavel Lhoták

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A series of calixarenes substituted with 2-acetamido-2-deoxy-beta-D-glucopyranose linked by a thiourea spacer was prepared and tested for binding activity to heterogeneously expressed activation receptors of the rat natural killer cells NKR-P1, and the receptor CD69 (human NK cells, macrophages). In the case of NKR-P1, the binding affinity of(More)
S-alkylation of all four thiacalix[4]arene conformations was accomplished using alkyl triflates. The corresponding sulfonium salts are formed in a highly regio- and stereoselective manner depending on the conformation used. Interestingly, only mono- or disubstituted sulfonium salts can be prepared. Although many regio- and stereoisomers are theoretically(More)
Monohalogenation of thiacalix[4]arene in the cone conformation gave either the meta- or para-substituted isomers depending on the halogen and reaction conditions used. Surprisingly, the same reaction with the 1,3-alternate conformer led only to the meta isomer. This is the first example of such a conformation-dependent regioselectivity in(More)
We synthesized 25,26,27,28-tetrakis(11-sulfanylundecyloxy)calix[4]arene (CALIX) sensitive to dopamine and confirmed its structure by (1)H NMR and mass spectrometry. Chemisorption of CALIX molecules or their mixtures with 1-dodecanethiols (DDT) or hexadecanethiols (HDT) resulted in formation of compact low permeable monolayers as revealed by cyclic(More)
[structure: see text] Appending tetraphenylporphyrin units to the calix[4]arene skeleton via the ureido function leads to novel anion receptors designed for anion and/or cation detection by UV-vis spectroscopy. Calixarenes in the cone or 1,3-alternate conformations bearing two ureido moieties on the upper rim represent well-preorganized cavities where the(More)
The introduction of a 2-pyridylsulfoxide moiety into the upper rim of calix[4]arenes enabled the synthesis of unprecedented derivatives with intramolecularly bridged meta positions of two neighbouring aromatic subunits. Palladium-catalysed double C-H activation thus represents a straightforward way to a completely novel type of calixarenes.
Regioselective derivatization via an organomercury intermediate allowed for the introduction of carboxylic acid functionality into the meta position of the calix[4]arene skeleton. Intramolecular Friedel-Crafts cyclization led to a novel type of calixarene containing a ketone bridging moiety. Subsequent attack of the ketone by organometallic compounds(More)
To reveal the alternative ways for upper-rim thiacalixarene derivatization, the formylation reactions (Gross and/or Duff conditions) of the corresponding tetrapropoxythiacalix[4]arene immobilized in the 1,3-alternate conformation were systematically studied. Surprisingly, albeit using an excess of the formylation agent, only two formyl groups were(More)
The meta-iodo derivative, fixed in the cone conformation, enables the gram-scale preparation of a meta-bridged calix[4]arene. This intermediate, possessing a fluorene moiety within the macrocyclic skeleton, can be regioselectively alkylated on the corresponding methylene bridge to form a unique substitution pattern in classical calixarene chemistry.
NMR spectroscopy, X-ray diffraction analysis, and quantum chemical calculations were used for conformational behavior study of partially alkylated thiacalix[4]arenes bearing methyl (1), ethyl (2), or propyl (3) groups at the lower rim. The conformational properties are governed by two basic effects: (i) stabilization by intramolecular hydrogen bonds, and(More)