Studien zur Herkunft spätmittelalterlicher Studenten am Beispiel Greifswald (1456-1524)

Gegenstand der Arbeit sind Studenten und Universitäten im späten Mittelalter, wobei die 1456 gegründete Ostseeuniversität Greifswald den Ausgangspunkt der Studien bildet. Anhand einer systematischen Auswertung der Greifswalder Matrikel werden die geographischen und sozialen Herkunftsstrukturen der Studenten analysiert, die sich bis 1524 dort inskribierten. Damit folgt die Arbeit einer sozialgeschichtlichen Perpektive der Universitätshistoriographie. Das zentrale Ergebnis liegt in dem Nachweis, daß bereits im Jahrzehnt um 1500 die Universität Greifswald sich zur Landesuniversität entwickelt hat. Damit ist für eine Universität die Grundsatzfrage gelöst, die insgesamt für die europäische Universitätsgeschichte noch ihrer Klärung harrt: Wann und durch welche Umstände ist die im Prinzip universal gedachte Universität zu jener Hochschule des Landes geworden, als die sie seit dem ausgehenden 17. und im 18. Jahrhundert entgegentritt. Die Arbeit untersucht in einem ersten Kapitel die Frequenz der Universität Greifswald zwischen 1456 und 1524 sowie die Aussagequalität der Matrikel. In einem weiteren Kapitel werden die sozialen Herkunftsstrukturen der Studenten beleuchtet, die den sozialgeschichtlichen Hintergrund eines mittelalterlichen Universitätsstudiums belegen. Die Angaben zur Gebührenzahlung der Studenten machen deutlich, daß sich auch innerhalb der Universität eine starke soziale Differenzierung vollzog. Dabei gab es einzelne Phasen, in denen der Prozentsatz zahlungskräftiger Studenten besonders niedrig war, doch zählten Greifswalder Studenten gegenüber anderen Universitäten zu den zahlungskräftigsten Universitätsbesuchern, wofür man die wohlhabende Oberschicht wendischer Hansestädte als Ursache anf\ihren kann. Im Hauptteil der Arbeit werden die Herkunftsorte und -regionen der Studenten erfaßt, die von über 90 Prozent der etwa 3000 Studenten angegeben wurden. Der sich wandelnde Einzugsbereich der Greifswalder Studenten wird außerdem durch Karten und Grafiken veranschaulicht. Gegen Ende des Betrachtungszeitraums zeigt sich, wie aus der "Universität für den Norden Europas" eine reine Landesuniversität Pommerns geworden ist. In einer Art Gegenprobe werden in einem weiteren Arbeitsschritt die Matrikel anderer Universitäten auf Studenten aus Pommern und Nachbarländern hin untersucht, um so das zentrale Ergebnis vom Wandel der Greifswalder Universität zu einer reinen Landesuniversität zu überprüfen bzw. zu stützen. Dabei wird deutlich, wie sich das dichter werdende Universitätsnetz in den Immatrikulationszahlen der einzelnen Universitäten widerspiegelt: Vor allem die Universitätsgründungen in Wittenberg (1502) und Frankfurt/Oder (1505) sind für den Rückgang überregionaler Studenten in Greifswald zu Beginn des 16. Jahrhunderts verantwortlich. Außerdem wird der in den Sozialstrukturen der Greifswalder Studenten sichtbar gewordene prozentuale Rückgang wohlhabender Studenten durch die gestiegene Gesamtfrequenz aus Pommern und die dadurch verbreiterte soziale Herkunftsbasis erklärbar

1,5-bifunctional organomagnesium reagents for the direct transformation of esters into arenes

For the sustainable and economical supply of products relevant to our society, the development of new methods based on main group elements is indispensable. Arenes are privileged molecular scaffolds due to their stability, rigidity and their manifold use in functional or bioactive entities. Nowadays, transition metal catalyzed cross-coupling reactions are the most frequently employed and efficient methods to functionalize arenes by means of C – C bond formation. However, they require prefunctionalized coupling partners and remaining catalyst impurities are difficult to be removed to the required levels. Thus, transition-metal-free methods to synthesize substituted arenes from readily available starting materials are highly desirable. Carboxylic acid ester are ubiquitous intermediates in organic synthesis and are therefore the ideal substrates for the synthesis of arene derivatives. In this thesis the development of a one step transformation of carboxylic acid esters into substituted arenes with 1,5 bifunctional organomagnesium reagents is described. The Grignard reagents react with the esters in a twofold nucleophilic addition, which is followed by an ensuing 1,4 elimination, incorporating the carboxylic carbon-atom into the newly formed aromatic ring. Various arene derivatives like substituted benzenes and polycyclic aromatic hydrocarbons like anthracenes, tetracenes and pentacenes were synthesized in yields up to 99%. The remarkable advancement of mild halogen magnesium exchange reactions over the recent years allowed to access a 1,5-dimagnesium-1,4-pentadiene reagent from the corresponding diiodo-precursor. The reagent was utilized to efficiently convert esters into substituted benzene. Various derivatives such as aryl-, heteroaryl-, alkenyl- and alkyl-substituted benzenes were prepared in yields up to 82% by this direct [5+1]-benzene-forming reaction under mild conditions. The corresponding 1,5 bifunctional bifunctional arylic organomagnesium reagents were obtained by the direct oxidative addition of elemental magnesium into the Ar – Br bond of o,o' dibromoarylmethanes. These reagents show a higher stability in comparison to the pentadiene-Grignard reagent and react with esters at room temperature with extraordinary efficiency. Even mono-substituted pentacenes, sensitive to light and oxygen can be successfully prepared by this mild method in yields up to 97%. An organomagnesium alkoxide reagent prepared by a deprotonation-magnesiation sequence from readily available bis(2-bromophenyl)methanol allowed the synthesis of disubstituted anthracenes and anthrones. Halogen-substituted and reduced derivatives were obtained by variation of the workup conditions in one synthetic step. Workup with aq. HCl (1M) allowed to isolate the corresponding cis-diol in excellent yield. Remarkably, a high level of diastereoselectivity was observed, which presumably is a result of coordination of the alkoxide metal to the ester carboxyl oxygen in the second addition step. Based on this observation, the preparation of a chiral 1,5 bifunctional organomagnesium alkoxide reagent derived from a chiral propargylic alcohol was developed. This allowed to implement a stereoselective direct ester to naphthalene transformation by means of central to axial chirality conversion giving direct access to valuable axially chiral TMS-substituted naphthalenes. Full stereospecificity was observed with substrates with sufficient substitution. Moreover, products with low rotational barriers could be efficiently prepared under the mild reaction conditions with good stereoselectivity. Intriguingly, complete reversal of the stereoselectivity was observed in the transformation of a unprotected deprotonated indole-ester

Towards the Industrial Implementation of Mn-based Catalyst for the Hydrogenation of Ketones and Carboxylic Esters

There is a constant pressure in industry to move away from platinum group metals (PGM) and achieve more environmentally friendly and sustainable production processes in the future. Recently developed Mn-based catalysts offer an interesting opportunity to complement established catalysts based on Ru. In this article, recent achievements in the field are highlighted and recent achievements in the collaboration of Solvias AG with the group of Prof. M. Clarke towards the implementation of these catalysts on industrial scale are outlined

Direct Transformation of Esters into Arenes with 1,5-Bifunctional Organo­magnesium Reagents

A direct transformation of carboxylic acid esters into arenes with 1,5-bifunctional organomagnesium reagents is described. This efficient and practical method enables the one-step defunctionalization of various carboxylic acid esters to prepare benzene, anthracene, tetracene, and pentacene derivatives. A double nucleophilic addition of the 1,5-organodimagnesium reagent to the ester is followed by an immediate 1,4-elimination reaction that leads to the direct [5+1] formation of a new aromatic ring

A surface acoustic wave-driven micropump for particle uptake investigation under physiological flow conditions in very small volumes

Static conditions represent an important shortcoming of many in vitro experiments on the cellular uptake of nanoparticles. Here, we present a versatile microfluidic device based on acoustic streaming induced by surface acoustic waves (SAWs). The device offers a convenient method for introducing fluid motion in standard cell culture chambers and for mimicking capillary blood flow. We show that shear rates over the whole physiological range in sample volumes as small as 200 mu L can be achieved. A precise characterization method for the induced flow profile is presented and the influence of flow on the uptake of Pt-decorated CeO2 particles by endothelial cells (HMEC-1) is demonstrated. Under physiological flow conditions the particle uptake rates for this system are significantly lower than at low shear conditions. This underlines the vital importance of the fluidic environment for cellular uptake mechanisms

Catalytic Arene-forming Aldol Condensation: Stereoselective Synthesis of Rotationally Restricted Aromatic Compounds

By taking inspiration from the fascinating biosynthetic machinery that creates aromatic polyketides, our group investigates analogous reactions catalyzed by small molecules. We are particularly captivated by the prospects of intramolecular aldol condensation reactions to generate different rotationally restricted aromatic compounds. In a first project of our independent research group, a highly stereoselective amine catalyzed synthesis of axially chiral biaryls, tertiary aromatic amides and oligo-1,2-naphthylenes has been developed. In this article, we outline the twists and turns for our escape from the aromatic flatland to structurally intriguing chiral arene scaffolds relevant for various fields of application

Genetic risk and a primary role for cell-mediated immune mechanisms in multiple sclerosis.

Multiple sclerosis is a common disease of the central nervous system in which the interplay between inflammatory and neurodegenerative processes typically results in intermittent neurological disturbance followed by progressive accumulation of disability. Epidemiological studies have shown that genetic factors are primarily responsible for the substantially increased frequency of the disease seen in the relatives of affected individuals, and systematic attempts to identify linkage in multiplex families have confirmed that variation within the major histocompatibility complex (MHC) exerts the greatest individual effect on risk. Modestly powered genome-wide association studies (GWAS) have enabled more than 20 additional risk loci to be identified and have shown that multiple variants exerting modest individual effects have a key role in disease susceptibility. Most of the genetic architecture underlying susceptibility to the disease remains to be defined and is anticipated to require the analysis of sample sizes that are beyond the numbers currently available to individual research groups. In a collaborative GWAS involving 9,772 cases of European descent collected by 23 research groups working in 15 different countries, we have replicated almost all of the previously suggested associations and identified at least a further 29 novel susceptibility loci. Within the MHC we have refined the identity of the HLA-DRB1 risk alleles and confirmed that variation in the HLA-A gene underlies the independent protective effect attributable to the class I region. Immunologically relevant genes are significantly overrepresented among those mapping close to the identified loci and particularly implicate T-helper-cell differentiation in the pathogenesis of multiple sclerosis

From Academia to the Market – Air-stable Ni(II)/Josiphos Catalysts

The design, synthesis, commercialization and application of air stable Ni(II)/Josiphos complexes has been realized in a collaboration between Solvias and ICBMS (University Lyon 1). The Ni-complexes  are utilized as versatile precatalysts for diverse cross coupling reactions. Apart from being active in established C–C and C–N couplings at low catalyst loadings, the novel Ni-precatalysts enabled the development of the challenging monoarylation of ammonia, ammonia surrogates and even alkylammonium chlorides with aryl carbamates. Finally, the alpha-arylation of acetone with aryl chlorides, carbamates and pivalates was demonstrated using the Ni(II)/Josiphos precatalysts