A novel synthesis of linear polyenes via conjugate addition of cuprates to α,β-γ,δ-diunsaturated sulfones followed by SO2 extrusion

The two 1,3-butadienyl 2-propenyl sulfones $\text{5}$ and $\text{6}$, 1,3,5-heptatriene synthons, have been transformed into the tri- and tetraenes $\text{1}$ - $\text{4}$ by alkylcuprate addition and Ramberg-Bäcklund SO₂ extrusion. The reaction stereochemistry is discussed.     

Durch wasserstoff-transfer induzierte radikal-eliminierungen aus ortho-substituierten benzoesäuremethylestern

The investigation of some ²H-labelled compounds as well as the analysis of energetic properties (appearance potential measurement, kinetic energy release) reveal some unusual elimination of radicals (CH₃^., OH^. resp. CHO^.) from ortho substituted bencoic acid methyl esters. It can be shown that most of the reactions are induced by a novel hydrogen transfer to the carboxyl function.     

On the maximum size of Erdős-Ko-Rado sets in H(2d+1, q^2)

Erd?s-Ko-Rado sets in finite classical polar spaces are sets of generators that intersect pairwise non-trivially. We improve the known upper bound for Erd?s-Ko-Rado sets in \(H(2d+1, q^2)\) for \(d>2\) and \(d\) even from approximately \(q^{d^2+d}\) to \(q^{d^2+1}.\)      

Dissipation-induced instabilities and symmetry

The paradox of destabilization of a conservative or non-conservative system by small dissipation,or Ziegler’s paradox(1952),has stimulated a growing interest in the sensitivity of reversible and Hamiltonian systems with respect to dissipative perturbations.Since the last decade it has been widely accepted that dissipation-induced instabilities are closely related to singularities arising on the stability boundary,associated with Whitney’s umbrella.The first explanation of Ziegler’s paradox was given(much earlier)by Oene Bottema in 1956.The aspects of the mechanics and geometry of dissipation-induced instabilities with an application to rotor dynamics are discussed.     

Synthesis, crystal structure and antiradical effect of copper(II) Schiff base complexes containing five-, six- and unusual seven-membered rings

The synthesis and solid-state structure of mononuclear copper(II) complexes [Cu(SAIB)(H(2)O)(2)] (1), [Cu(SBAIB)(H(2)O)(2)]·H(2)O (2) and [Cu(SGABA)(H(2)O)(2)] (3) are described. Schiff base ligands H(2)SAIB, H(2)SBAIB and H(2)SGABA chelate the copper(II) ion in an O,N,O tridentate fashion. The square-pyramidal geometry of the final complexes is completed by two water ligands. The formation of an unusual seven-membered ring in the set of copper(II) N-salicylidene-aminoacidates is reported. Compounds 1-3 were evaluated by the antiradical activity assay.     

Elastomeric hydrogels by polymerizing silicone microemulsions

Robust, transparent elastomeric hydrogels encoded with a bicontinuous structure result from the sequential photopolymerization of the aqueous hydroxyethyl methacrylate phase and crosslinking of the silicone phase of a silicone microemulsion stabilized with an acrylate-functional silicone-poly(ethylene glycol) surfactant.     

Integrability and Non-integrability of Hamiltonian Normal Forms

Acta Applicandae Mathematicae - This paper summarizes the present state of integrability of Hamiltonian normal forms and it aims at characterizing non-integrable behaviour in higher-dimensional...