Alkoxyallene‐Based LANCA Three‐Component Synthesis of 1,2‐Diketones, Quinoxalines, and Unique Isoindenone Dimers and a Computational Study of the Isoindenone Dimerization

A series of β‐alkoxy‐β‐ketoenamides was prepared by the well‐established LANCA three‐component reaction of lithiated 1‐(2‐trimethylsilylethoxy)‐substituted allenes, nitriles, and α,β‐unsaturated carboxylic acids. The α‐tert‐butyl‐substituted compounds were smoothly converted into the expected 1,2‐diketones by treatment with trifluoroacetic acid. A subsequent condensation of the 1,2‐diketones with o‐phenylenediamine provided the desired highly substituted quinoxalines in good overall yield. Surprisingly, the α‐phenyl‐substituted β‐alkoxy‐β‐ketoenamides investigated afford not only the expected 1,2‐diketones, but also pentacyclic compounds with an anti‐tricyclo[4.2.1.12,5]deca‐3,7‐diene‐9,10‐dione core. These interesting products are very likely the result of an isoindenone dimerization which was mechanistically studied with the support of DFT calculations. Under the strongly acidic reaction conditions, a stepwise reaction is likely leading to a protonated isoindenone as reactive intermediate. It may first form a van der Waals complex with a neutral isoindenone before the two regio‐ and diastereoselective ring forming steps occur. Interestingly, two neutral or two protonated isoindenones are also predicted to dimerize giving the observed pentacyclic product

Bekämpfung der Blutlaus durch Freilassung von Blutlauszehrwespen aus Massenzucht

Ziel des Projektes war die Erarbeitung eines Verfahrens zur Regulierung der Blutlaus (Eriosoma lanigerum), eines wirtschaftlich bedeutenden Schädlings im ökologischen Obstbau, gegen den es momentan keinerlei wirksame Bekämpfungsmöglichkeiten gibt. Hierzu wurde versucht, aus der Erfahrung vorangegangener Versuchsergebnisse ein Verfahren zur Bekämpfung der Blutlaus durch den Einsatz von Blutlauszehrwespen (Aphelinus mali) aus einer Nützlingszucht zu entwickeln und zur Praxisreife zu bringen. Die Zehrwespe ist ein natürlich vorkommender Gegenspieler, dem es aufgrund mangelnder Synchronisation zwischen Schädling und Nützling nicht rechtzeitig gelingt, den Schaden durch die Blutlaus zu verhindern. 2004 konnten mit dem Einsatz von parasitierten Blutlausmumien keine zufrieden stellenden Ergebnisse erzielt werden. Die Produktion der Mumien war für den Nützlingsproduzenten mit erheblichen Schwierigkeiten verbunden. Die wünschenswerte Lagerung der Mumien führte zu hoher Mortalität und Verzögerungen im Schlupfverlauf. Die Versuche mit adulten Zehrwespen 2005 zeigten im Gegensatz zu den Versuchen mit Mumien im Vorjahr auswertbare Ergebnisse. Allerdings reichten auch hier die erzielten Wirkungsgrade nicht für eine vollständige Bekämpfung und damit der Vermeidung von Schäden an den Bäumen aus. Die Parasitierungsleistung von A. mali wird im Wesentlichen von zwei Faktoren beeinflusst: der Temperatur und der vorhandenen Lichtmenge. Unter normalen Witterungsbedingungen macht daher der zeitige Einsatztermin im Frühjahr keinen Sinn, da A. mali in der Regel keine geeigneten Vermehrungsbedingungen vorfindet. Zudem ist A. mali der Blutlaus in Bezug auf die Vermehrungsrate unterlegen. Ein Kombinationsverfahren mit einer Ölspritzung und nachfolgender Freilassung von Zehrwespen unter klimatisch günstigeren Bedingungen wurde 2006 durchgeführt und brachte mit Wirkungsgraden von etwa 60 % ähnliche Ergebnisse wie 2005. Die Blutlauszehrwespe A. mali ist in der Lage, den Befall durch die Blutlaus zu reduzieren, jedoch nicht zu regulieren und Schäden an den Bäumen vollständig zu verhindern

Control of the apple sawfly Hoplocampa testudinea Klug in organic fruit growing and possible side effects of control strategies on Aphelinus mali Haldeman and other beneficial insects

The effect of Quassia extract on eggs and larvae of the apple sawfly Hoplocampa testudinea was studied. The efficacy of this extract is mainly due to an oral toxicity to the neonate sawfly larvae. The main active ingredients, Quassin and Neoquassin, were tested separately. Wheras Quassin has a considerable efficacy also on older larvae, Neoquassin is less efficient in this case. While Quassin and Neoquassin are found in different Quassia sources in varying relations to each other and have different efficacy, they have to be considered separately in the definition of extract quality by the content of active ingredients. These findings mean, that the “egg maturity” is not important for application date. Nevertheless, the application must take place before the larvae hatch. It was shown that low rates of Quassin (4-6 g/ha) can show very good results in the field, in other cases the rates necessary for good efficacy are much higher. This corresponds to farmers experience. Several factors as application technique and the condition of the blossom must be taken in consideration and will be object of further studies. The side effects of Quassin, Neoquassin and Quassia extract on Aphelinus mali and other beneficial arthropods were tested. Quassia is harmless to all organisms tested

Regulierung der Apfelsägewespe im Ökologischen Obstbau und Nebenwirkungen der Strategien auf die Blutlauszehrwespe

The effects of Quassia extract on eggs and larvae of the apple sawfly Hoplocampa testudinea were studied in the laboratory. The efficacy of this extract was mainly due to an oral toxicity to neonate sawfly larvae. The main active ingredients, Quassin and Neoquassin, were tested sepa-rately as pure substances. While Quassin had a considerable efficacy also on older larvae, Neo-quassin was less efficient in this case. Since Quassin and Neoquassin were found in different Quassia sources in varying relations to each other and had different efficacy, they have to be considered separately in the definition of extract quality by the content of active ingredients. This requires the application of Quassia extracts before larval hatch. It was shown that low concentra-tions of Quassin (4-6 g/ha) can achieve very good control in the field, in other cases the concentra-tions for good efficacy are much higher. These varying results seem to be connected with applica-tion technique and application date. Trials in 2004 showed that the best way of application is with plenty of water (500 to 1000 l/ha) and the best date is during the stage when blossom is fading. The side effects of Quassin, Neoquassin and Quassia extract on Aphelinus mali and other benefi-cial arthropods were tested. Quassia is harmless to all organisms tested

Experimental study of ultracold neutron production in pressurized superfluid helium

We have investigated experimentally the pressure dependence of the production of ultracold neutrons (UCN) in superfluid helium in the range from saturated vapor pressure to 20bar. A neutron velocity selector allowed the separation of underlying single-phonon and multiphonon pro- cesses by varying the incident cold neutron (CN) wavelength in the range from 3.5 to 10{\AA}. The predicted pressure dependence of UCN production derived from inelastic neutron scattering data was confirmed for the single-phonon excitation. For multiphonon based UCN production we found no significant dependence on pressure whereas calculations from inelastic neutron scattering data predict an increase of 43(6)% at 20bar relative to saturated vapor pressure. From our data we conclude that applying pressure to superfluid helium does not increase the overall UCN production rate at a typical CN guide.Comment: 18 pages, 8 figures Version accepted for publication in PR

Biologische Bekämpfung der Blutlaus Eriosoma lanigerum HAUSM. durch den Einsatz der Blutlauszehrwespe Aphelinus mali HALD.

The release of Aphelinus mali HALD. from artificial rearing for the control of Woolly Apple Aphid (Eriosoma lanigerum HAUSM.) was tested in field trials. The release of adults proved to be more suitable than the release of cards with parasitized mummies as practised in the first trial. Setting free adult A. mali at the beginning of June reduced the aphid population, though its efficiency was not high enough to prevent damage of the trees totally. The practical applications of A. mali in early spring (after blossom) were not effective because climatic conditions were not suitable enough. The fertility of A. mali depends on temperature and light intensity. The application of Micula (rape oil) and T-S forte reduced the growth of the aphid population effectively. These substances may be used in a combined strategy to improve the successful subsequent release of A. mali. Possible phytotoxic effects, however, must be considered in this context

A multifunctional chemical cue drives opposing demographic processes and structures ecological communities

Foundation species provide critical resources to ecological community members and are key determinants of biodiversity. The barnacle Balanus glandula is one such species and dominates space among the higher reaches of wave-swept shores (Northeastern Pacific Ocean). This animal produces a cuticular glycoprotein (named "MULTIFUNCin") of 199.6\ua0kDa, and following secretion, a 390\ua0kDa homodimer in native form. From field and lab experiments, we found that MULTIFUNCin significantly induces habitat selection by conspecific larvae, while simultaneously acting as a potent feeding stimulant to a major barnacle predator (whelk, Acanthinucella spirata). Promoting immigration via settlement on the one hand, and death via predation on the other, MULTIFUNCin drives opposing demographic processes toward structuring predator and prey populations. As shown here, a single compound is not restricted to a lone species interaction or sole ecological function. Complex biotic interactions therefore can be shaped by simple chemosensory systems and depend on the multifunctional properties of select bioactive proteins

On Landau theory and symmetric energy landscapes for phase transitions

The aim of this presentation is the development of a general approach for modelling the global complex energy landscapes of phase transitions. For the sake of clarity and brevity the exposition is restricted to martensitic phase transition (i.e., diffusionless phase transitions in crystalline solids). The methods, however, are more broadly applicable. Explicit energy functions are derived for the cubic-to-tetragonal phase transition, where data are fitted for InTl. Another example is given for the cubic-to-monoclinic transition in CuZnAl. The resulting energies are defined globally, in a piecewise manner. We use splines that are twice continuously differentiable to ensure sufficient smoothness. The modular (piecewise) technique advocated here allows for modelling elastic moduli, energy barriers and other characteristics independent of each other. (C) 2007 Elsevier Ltd. All rights reserved

Biological Control of Woolly Apple Aphid (Eriosoma lanigerum HAUSM.) with Aphelinus mali HALD.

The release of Aphelinus mali HALD. from artificial rearing for the control of Woolly Apple Aphid (Eriosoma lanigerum HAUSM.) was tested in field trials. The release of adults proved to be more suitable than the release of cards with parasitized mummies as practised in the first trial. Setting free adult A. mali at the beginning of June reduced the aphid population, though its efficiency was not high enough to prevent damage of the trees totally. The practical applications of A. mali in early spring (after blossom) were not effective because climatic conditions were not suitable enough. The fertility of A. mali depends on temperature and light intensity. The application of Micula (rape oil) and T-S forte reduced the growth of the aphid population effectively. These substances may be used in a combined strategy to improve the successful subsequent release of A. mali. Possible phytotoxic effects, however, must be considered in this context