Bericht über das „Symposium on Coagulation and Coagulant Aids“ vom 1. bis 3. April 1963 in Los Angeles,Cal. (USA)

Ohne Zusammenfassung     

On the behaviour of the (Z)-phenylhydrazones of some 5-alkyl-3-benzoyl-1,2,4-oxadiazoles in solution and in the gas phase: kinetic and spectrometric evidence in favour of self-assembly

Rate constants, k_A,R, for the rearrangement of the (Z)-phenylhydrazones (1a-e) of a series of 5-alkyl-3-benzoyl-1,2,4-oxadiazoles substituted at C(5) with linear alkyl chains of different length (from C₄ up to C₁₂) into the relevant 4-acylamino-2,5-diphenyl-1,2,3-triazoles (2a-e) have been measured in dioxan/water in the base-catalyzed region (pS⁺ 10.5-12.6). For each substrate log k_A,R are linearly related to pS⁺. The significant decrease of the slopes of these straight lines (from 0.96 down to 0.78) upon increasing the length of the linear alkyl chain at C(5) and that of the reactivity (down to 14-26%) upon increasing the substrate concentration suggest a decrease of the polarity of the ‘actual’ reaction medium and provide indirect evidence of the tendency of the substrates (Z)-1a-e to self-assemble. To confirm the above outcome direct evidence of the formation of self-assemblies in solution were obtained from ¹H NMR and spectrofluorimetry measurements while ESI-MS experiments point out the presence of aggregated substrates also in the gas phase.     

A new route to thiopyran S,S-dioxide derivatives via an overall ring-enlargement protocol from 3-nitrothiophene

(1E,3Z)-1-Aryl-4-methanesulfonyl-2-nitro-1,3-butadienes (8), derived from the initial ring-opening of 3-nitrothiophene (5), have been found to undergo a facile base-induced cyclization leading to thiopyran S,S-dioxides (9), thus furnishing a further example of effective ring-enlargement from 5- to 6-membered sulfur heterocycles. Compounds 9 are obtained as single racemic mixtures in satisfactory yields; they still contain a nitrovinylic moiety, which can be exploited for further modifications targeted to new derivatives endowed with either synthetic or pharmacological potentialities e.g., in the field of L-type Ca²⁺-channel blockers.     

"Click"-modification of a functionalized poly(3,4-ethylenedioxythiophene) (PEDOT) soluble in organic solvents

A PEDOT-based conductive copolymer soluble in organic solvents was synthesized electrochemically using dihexyl-EDOT and azidomethyl-EDOT as monomers and was successfully post-functionalized by "click"-cycloaddition reaction with a functionalized terminal alkyne under mild heterogeneous conditions.     

Preparation and characterization of uniform drug particles: dehydrocholic acid

Two methods for the preparation of uniform dispersions of dehydrocholic acid of different morphologies are described. In the first case, the drug was dissolved in acetone and then re-precipitated by adding a non-solvent (either water or an aqueous stabilizer solution), which yielded rod-like particles. In the second procedure, spheres, consisting of small elongated subunits, were obtained by acidification of basic aqueous solutions of the drug. The resulting particles were characterized in terms of their structure and surface charge characteristics.     

Rigid orthogonal bis-TEMPO biradicals with improved solubility for dynamic nuclear polarization

The synthesis and characterization of oxidized bis-thioketal-trispiro dinitroxide biradicals that orient the nitroxides in a rigid, approximately orthogonal geometry are reported. The biradicals show better performance as polarizing agents in dynamic nuclear polarization (DNP) NMR experiments as compared to biradicals lacking the constrained geometry. In addition, the biradicals display improved solubility in aqueous media due to the presence of polar sulfoxides. The results suggest that the orientation of the radicals is not dramatically affected by the oxidation state of the sulfur atoms in the biradical, and we conclude that a biradical polarizing agent containing a mixture of oxidation states can be used for improved solubility without a loss in performance.     

Strengthening the Connection between Science,Society and Environment to Develop Future French and European Bioeconomies: Cutting-Edge Research of VAALBIO Team at UCCS

The development of the future French and European bioeconomies will involve developing new green chemical processes in which catalytic transformations are key. The VAALBIO team (valorization of alkanes and biomass) of the UCCS laboratory (Unité de Catalyse et Chimie du Solide) are working on various catalytic processes, either developing new catalysts and/or designing the whole catalytic processes. Our research is focused on both the fundamental and applied aspects of the processes. Through this review paper, we demonstrate the main topics developed by our team focusing mostly on oxygen- and hydrogen-related processes as well as on green hydrogen production and hybrid catalysis. The social impacts of the bioeconomy are also discussed applying the concept of the institutional compass.