Direkte Kupplung von Steroiden an Eiwei? durch reduktive Aminierung zur Gewinnung spezifischer Antik?rper

Ohne Zusammenfassung

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Direct coupling of steroids and protein by reductive amination for the production of specific antibodies

     

Lanthanoid coordination with a tetrazole-substituted calix[4]diquinone and calix[4]dihydroquinone

The tetrazole-functionalised calixdiquinone 5,17-di-tert-butyl-26,28-bis-(1H-tetrazole-5-ylmethoxy)-calix[4]-25,27-diquinone Q was synthesised by chemical oxidation of the bis-tetrazole calix[4]arene precursor using PbO₂/HClO₄. The single crystal X-ray structure determination of Q confirmed the structure and showed binding of a water molecule in the solid state. Chemical reduction of Q to the dihydroquinone QR was achieved using N,N-diethylhydroxylamine. Comparison of the solution phase photophysical properties of Q or QR in the presence of terbium ions showed significant excitation only with QR, suggesting redox switching of the photophysical response may be possible with this or similar receptor.     

Bildung von HfSiO4-Einkristallen durch chemische Transportreaktion

On the Formation of HfSiO₄ Single Crystals by Chemical Transport Reactions The formation of synthetic hafnon single crystals, HfSiO₄, during chemical transport reactions in order to prepare CuCrHfSe₄ was observed. Characterization of the crystals was by electron microprobe analysis and X-ray methods. The crystals are tetragonal, a = 658.0(2), c = 598.0(6) pm, the space group is I4₁/amd (zircon structure). Refined atom parameters and details of preparation of these crystals by chemical transport reactions starting from mixtures of HfO₂ and SiO₂ are reported.     

Über Reaktionen mit Betainen, 21. Mitt. Über die Bildung von Formazylverbindungen durch Kupplung von S-Betainen mit 4-Nitrobenzol-diazonium-tetrafluorborat

Dimethylsulfonium acetic acid betaine (1) and thiolanium acetic acid betaine (4) react with 4-nitrophenyldiazonium tetrafluoroborate (2) in aceticacid solution to give the formazyl compounds3 and5. Reaction of dimethylsulfonium- and thiolanium-trifluoroacetyl-methylide (9 and11, resp.) with compound2 leads to the phenylhydrazones10 and13, whereas trimethylammonium-trifluoroacetyl-methylide (14) reacts with formation of the formazane derivative15.

Herrn Prof. Dr. Dr. h. c.K. Kratzl, Universität Wien, mit besten Wünschen zur Vollendung des 70. Lebensjahres gewidmet.     

Stereoselective alkylation of thiacalix[4]arenes

A direct tetraalkylation of thiacalix[4]arenes using procedures well established in ‘classical’ calixarene chemistry usually gives the 1,3-alternate conformers as the main product (n-PrI/K₂CO₃/acetone) while the cone conformers are obtained only in very poor yields (n-PrI/NaH/DMF). Surprisingly, the so far almost inaccessible cone conformers can be prepared in high yields using the two-step procedure: dialkylation-dialkylation, opening the way for their further utilisation in supramolecular chemistry.