Recent advances in microwave-assisted combinatorial synthesis and library generation

Progress and developments made in microwave-assisted combinatorial synthesis and library production since 2002 are reviewed. The use of microwave technology in both solution and solid phase synthesis is discussed with special reference to agrochemical applications where appropriate.     

Circular dichroism of sesquiterpene-umbelliferone ethers and structure elucidation of a new derivative isolated from the gum resin “Asa Foetida”

The CD spectra of 16 naturally occurring sesquiterpene-umbelliferone ethers, including the complete set of farnesiferol A isomers with all acetates and 6-oxoderivatives, are reported over the significant wavelength range of 350–200 nm. 11 compounds were isolated from an Asa Foetida sample and 5 further derivatives, already known as natural products, were obtained by acetylation orJones oxidation. In addition, a new compound — kamolonol (14) — was isolated. Its structure is characterized by twofold methyl migration in the drimenol derived sesquiterpene moiety.¹H-NMR, MS, IR, UV, and CD data of the new compound are discussed.Herrn Prof. Dr.K. Schlögl mit den besten Wünschen zum 60. Geburtstag gewidmet.     

New amides fromSpilanthes oleracea

In addition to the well known affinin [=spilanthol, (2E,6Z,8E)-deca-2,6,8-trienoic acid isobutylamide (1)], the corresponding 2-methyl-butylamide (2), and two new acetylenic alkamides were isolated fromSpilanthes oleracea L. by reversed phase medium pressure chromatography: (Z)-non-2-en-6,8-diynoic acid isobutylamide (3) and (Z)-dec-2-en-6,8-diynoic acid isobutylamide (4). The structures and their stereochemistries were elucidated by¹H-NMR,¹³C-NMR (2 and3), MS, UV, IR, and CD (2). The chemotaxonomic significance of the distribution of alkamides within theCompositae tribeHeliantheae is briefly discussed.

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Neue Amide ausSpilanthes oleracea (Kurze Mitteilung)

Zusammenfassung AusSpilanthes oleracea wurden neben dem seit langem bekannten Affinin [=Spilanthol, (2E,6Z,8E)-Deca-2,6,8-triensäureisobutylamid (1)] durch Umkehrphasen-Mitteldruckchromatographie das entsprechende 2-Methylbutylamid (2) und zwei neue acetylenische Alkamide isoliert: (Z)-Non-2-en-6,8-diinsäure-isobutylamid (3) und (Z)-Dec-2-en-6,8-diinsäure-isobutylamid (4). Die Strukturen und deren Stereochemie wurden mittels¹H-NMR,¹³C-NMR (2 und3), MS, UV, IR und CD (2) aufgeklärt. Die chemotaxonomische Bedeutung der Verbreitung von Alkamiden innerhalb der Compositen-TribusHeliantheae wird kurz diskutiert.

     

Exchange corrections to the density-density correlation function at a surface

The problem of calculating the density-density correlation function and of including the effects of exchange and correlation are discussed. It is shown in a model calculation how a particularly simple surface model can be easily extended to include exchange corrections. The effects of these corrections on the surface plasmon dispersion are found to be small.     

Aglairubine: Structure Revision of a Chemotaxonomically Interesting Bisamide in Aglaia (Meliaceae)

 The bisamide aglairubine was isolated from different Aglaia species. The original structure was revised on the basis of FDMS and 2D-NMR data. Since all isolates were obtained from species belonging to the section Amoora of the genus Aglaia, aglairubine might serve as a taxonomic marker.     

Ueber die Bestimmung der Blaus?ure im Kirschlorbeerwasser

Ohne Zusammenfassung     

New directions in perfluoroalkyl sulfonic acid–based proton-exchange membranes

Perfluoroalkyl sulfonic acid (PFSA) polymer membranes have enabled a variety of electrochemical energy storage and conversion devices such as fuel cells and flow batteries and material conversion devices such as electrolyzers to produce hydrogen and chlorine. For decades, a small group of simple copolymers were relied on in these applications. The practical limits for conductivity through lower equivalent weight are being approached for these polymers. Recently, the community has recognized the need for new PFSA ionomers with properties tailored to the specific needs of each application. An emerging area of importance is the manipulation of the diffusion properties of these polymers. For example, fuel cell membranes need to maintain good barrier properties as thicknesses are reduced, while ionomers with increased oxygen diffusion rates are sought for fuel cell electrodes. In recent years, the class of PFSA ionomers has expanded to include new side chain structures, new comonomers, and even hydrocarbon hybrid structures.     

Validation of an MPC Polymer Coating to Attenuate Surface‐Induced Crosstalk between the Complement and Coagulation Systems in Whole Blood in In Vitro and In Vivo Models

Artificial surfaces that come into contact with blood induce an immediate activation of the cascade systems of the blood, leading to a thrombotic and/or inflammatory response that can eventually cause damage to the biomaterial or the patient, or to both. Heparin coating has been used to improve hemocompatibility, and another approach is 2‐methacryloyloxyethyl phosphorylcholine (MPC)‐based polymer coatings. Here, the aim is to evaluate the hemocompatibility of MPC polymer coating by studying the interactions with coagulation and complement systems using human blood in vitro model and pig in vivo model. The stability of the coatings is investigated in vitro and MPC polymer‐coated catheters are tested in vivo by insertion into the external jugular vein of pigs to monitor the catheters' antithrombotic properties. There is no significant activation of platelets or of the coagulation and complement systems in the MPC polymer‐coated one, which was superior in hemocompatibility to non‐coated matrix surfaces. The protective effect of the MPC polymer coat does not decline after incubation in human plasma for up to 2 weeks. With MPC polymer‐coated catheters, it is possible to easily draw blood from pig for 4 days in contrast to the case for non‐coated catheters, in which substantial clotting is seen.