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  • ddc:510  (41)
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  • 2015-2019
  • 2005-2009  (41)
  • 1985-1989
  • 1970-1974  (788)
  • 1800-1809
Year
Language
  • 1
    Publication Date: 2020-08-05
    Description: Das heutige Leben ist durchdrungen von komplexen Technologien. Ohne Kommunikationsnetze, Internet, Mobilfunk, Logistik, Verkehrstechnik, medizinische Apparate, etc. könnte die moderne Gesellschaft nicht funktionieren. Fast alle dieser Technologien haben einen hohen Mathematikanteil. Der "normale Bürger"' weiss davon nichts, der Schulunterricht könnte dem ein wenig abhelfen. Einige mathematische Aspekte dieser Technologien sind einfach und sogar spielerisch intuitiv zugänglich. Solche Anwendungen, die zusätzlich noch der Lebensumwelt der Schüler zugehören, können dazu genutzt werden, die mathematische Modellierung, also die mathematische Herangehensweise an die Lösung praktischer Fragen, anschaulich zu erläutern. Gerade in der diskreten Mathematik können hier, quasi "nebenbei" mathematische Theorien erarbeitet und Teilaspekte (Definitionen, Fragestellungen, einfache Sachverhalte) durch eigenständiges Entdecken der Schüler entwickelt werden. Wir beginnen mit einigen Beispielen.
    Keywords: ddc:510
    Language: German
    Type: reportzib , doc-type:preprint
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  • 2
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    Publication Date: 2020-08-05
    Description: Den kürzesten Weg in einem Graphen zu finden ist ein klassisches Problem der Graphentheorie. Über einen Vortrag zu diesem Thema beim Tag der Mathematik 2007 von R. Borndörfer kam ich in Kontakt mit dem Konrad-Zuse-Zentrum (ZIB), das sich u.a. mit Wegeoptimierung beschäftigt. Ein Forschungsschwerpunkt dort ist im Rahmen eines Projekts zur Chipverifikation das Zählen von Lösungen, das, wie wir sehen werden, eng mit dem Zählen von Wegen zusammenhängt. Anhand von zwei Fragen aus der Graphentheorie soll diese Facharbeit unterschiedliche Lösungsmethoden untersuchen. Wie bestimmt man den kürzesten Weg zwischen zwei Knoten in einem Graphen und wie findet man alle möglichen Wege? Nach einer Einführung in die Graphentheorie und einer Konkretisierung der Probleme wird zunächst für beide eine Lösung mit auf Graphen basierenden Algorithmen vorgestellt. Während der Algorithmus von Dijkstra sehr bekannt ist, habe ich für das Zählen von Wegen einen eigenen Algorithmus auf der Basis der Tiefensuche entwickelt. Im zweiten Teil der Arbeit wird das Konzept der ganzzahligen Programmierung vorgestellt und die Lösungsmöglichkeiten für Wegeprobleme, die sich darüber ergeben. Schließlich wurden die vorgestellten Algorithmen am Beispiel des S- und U-Bahnnetzes von Berlin implementiert und mit Programmen, die die gleichen Fragen über ganzzahlige Programmierung lösen, verglichen.
    Keywords: ddc:510
    Language: German
    Type: reportzib , doc-type:preprint
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  • 3
    Publication Date: 2016-06-09
    Description: This paper is intended to be a first step towards the continuous dependence of dynamical contact problems on the initial data as well as the uniqueness of a solution. Moreover, it provides the basis for a proof of the convergence of popular time integration schemes as the Newmark method. We study a frictionless dynamical contact problem between both linearly elastic and viscoelastic bodies which is formulated via the Signorini contact conditions. For viscoelastic materials fulfilling the Kelvin-Voigt constitutive law, we find a characterization of the class of problems which satisfy a perturbation result in a non-trivial mix of norms in function space. This characterization is given in the form of a stability condition on the contact stresses at the contact boundaries. Furthermore, we present perturbation results for two well-established approximations of the classical Signorini condition: The Signorini condition formulated in velocities and the model of normal compliance, both satisfying even a sharper version of our stability condition.
    Keywords: ddc:510
    Language: English
    Type: reportzib , doc-type:preprint
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  • 4
    Publication Date: 2020-08-05
    Description: Most data networks nowadays use shortest path protocols to route the traffic. Given administrative routing lengths for the links of the network, all data packets are sent along shortest paths with respect to these lengths from their source to their destination. In this paper, we present an integer programming algorithm for the minimum congestion unsplittable shortest path routing problem, which arises in the operational planning of such networks. Given a capacitated directed graph and a set of communication demands, the goal is to find routing lengths that define a unique shortest path for each demand and minimize the maximum congestion over all links in the resulting routing. We illustrate the general decomposition approach our algorithm is based on, present the integer and linear programming models used to solve the master and the client problem, and discuss the most important implementational aspects. Finally, we report computational results for various benchmark problems, which demonstrate the efficiency of our algorithm.
    Keywords: ddc:510
    Language: English
    Type: reportzib , doc-type:preprint
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  • 5
    Publication Date: 2020-12-15
    Description: This paper introduces the "line connectivity problem", a generalization of the Steiner tree problem and a special case of the line planning problem. We study its complexity and give an IP formulation in terms of an exponential number of constraints associated with "line cut constraints". These inequalities can be separated in polynomial time. We also generalize the Steiner partition inequalities.
    Keywords: ddc:510
    Language: English
    Type: reportzib , doc-type:preprint
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  • 6
    Publication Date: 2020-08-05
    Description: Testing is the process of stimulating a system with inputs in order to reveal hidden parts of the system state. In the case of non-deterministic systems, the difficulty arises that an input pattern can generate several possible outcomes. Some of these outcomes allow to distinguish between different hypotheses about the system state, while others do~not. In this paper, we present a novel approach to find, for non-deterministic systems modeled as constraints over variables, tests that allow to distinguish among the hypotheses as good as possible. The idea is to assess the quality of a test by determining the ratio of distinguishing (good) and not distinguishing (bad) outcomes. This measure refines previous notions proposed in the literature on model-based testing and can be computed using model counting techniques. We propose and analyze a greedy-type algorithm to solve this test optimization problem, using existing model counters as a building block. We give preliminary experimental results of our method, and discuss possible improvements.
    Keywords: ddc:510
    Language: English
    Type: reportzib , doc-type:preprint
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  • 7
    Publication Date: 2021-08-05
    Description: Starting with the description of the Traveling Salesmen Problem formulation as given by van Vyve and Wolsey in the article Approximate extended formulations'', we investigate the effects of small variations onto the performance of contemporary mixed integer programming solvers. We will show that even minor changes in the formulation of the model can result in performance difference of more than a factor of 1000. As the results show it is not obvious which changes will result in performance improvements and which not.
    Keywords: ddc:510
    Language: English
    Type: reportzib , doc-type:preprint
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  • 8
    Publication Date: 2022-03-14
    Description: Orbitopes can be used to handle symmetries which arise in integer programming formulations with an inherent assignment structure. We investigate the detection of symmetries appearing in this approach. We show that detecting so-called orbitopal symmetries is graph-isomorphism hard in general, but can be performed in linear time if the assignment structure is known.
    Keywords: ddc:510
    Language: English
    Type: reportzib , doc-type:preprint
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  • 9
    Publication Date: 2019-01-29
    Description: Regional hyperthermia is a cancer therapy aiming at heating tumors using phased array applicators. This article provides an overview over current mathematical challenges of delivering individually optimal treatments. The focus is on therapy planning and identification of technical as well as physiological quantities from MR thermometry measurements.
    Keywords: ddc:510
    Language: English
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  • 10
    Publication Date: 2019-05-10
    Description: Reasons for the failure of adaptive methods to deliver improved efficiency when integrating monodomain models for myocardiac excitation are discussed. Two closely related techniques for reducing the computational complexity of linearly implicit integrators, deliberate sparsing and splitting, are investigated with respect to their impact on computing time and accuracy.
    Keywords: ddc:510
    Language: English
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  • 11
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    Publication Date: 2020-08-05
    Description: We investigate the computation of periodic timetables for public transport by mixed integer programming. After introducing the problem, we describe two mathematical models for periodic timetabling, the PERIODIC EVENT SCHEDULING PROBLEM (PESP) and the QUADRATIC SEMI-ASSIGNMENT PROBLEM. Specifically, we give an overview of existing integer programming (IP) formulations for both models. An important contribution of our work are new IP formulations for the PESP based on time discretization. We provide an analytical comparison of these formulations and describe different techniques that allow a more efficient solution by mixed integer programming. In a preliminary computational study, on the basis of standard IP solvers, we compare different formulations for computing periodic timetables. Our results justify a further investigation of the time discretization approach. Typically the timetable is optimized for the current traffic situation. The main difficulty with this approach is that after introducing the new timetable the passengers’ travel behavior may differ from that assumed for the computation. Motivated by this problem, we examine an iterative timetabling procedure that is a combination of timetable computation and passenger routing. We discuss the algorithmic issues of the passenger routing and study properties of the computed timetables. Finally, we confirm our theoretical results on the basis of an own implementation.
    Description: Wir untersuchen die Berechnung von Taktfahrplänen für den öffentlichen Verkehr mit gemischt-ganzzahliger Programmierung (MIP). Im Anschluss an die Problembeschreibung, stellen wir zwei mathematische Modellierungen vor, das PERIODIC EVENT SCHEDULING PROBLEM (PESP) und das QUADRATIC SEMI-ASSIGNMENT PROBLEM. Wichtiger Bestandteil ist ein Überblick über existierende ganzzahlige Formulierungen beider Modelle. Wir entwickeln neue ganzzahlige Formulierungen für das PESP auf der Basis von Zeitdiskretisierung. Diese werden analytisch miteinander verglichen und wir beschreiben verschiedene Techniken, die eine effizientere Lösung der Formulierungen mit gemischt-ganzzahliger Programmierung ermöglichen. In einer ersten Rechenstudie, unter Verwendung gängiger MIP-Löser, vergleichen wir verschiedene ganzzahlige Formulierungen zur Berechnung von Taktfahrplänen. Unsere Ergebnisse rechtfertigen eine weitere Untersuchung des Zeitdiskretisierungsansatzes. In der Regel werden Fahrpläne mit Bezug auf die gegenwärtige Verkehrssituation optimiert. Dies birgt jedoch folgendes Problem. Wenn der neue Fahrplan eingeführt wird, ist es möglich, dass die Passagiere ein anderes Fahrverhalten zu Tage legen, als für die Berechnung des Fahrplans angenommen wurde. Vor diesem Hintergrund behandeln wir ein iteratives Verfahren zur Berechnung von Taktfahrplänen. Dieses ist eine Kombination aus Fahrplanberechnung und Passagierrouting. Neben den algorithmischen Details des Passagierroutings untersuchen wir Eigenschaften der berechneten Fahrpläne. Abschließend bestätigen wir unsere theoretischen Ergebnisse auf Grundlage einer eigenen Implementierung des Verfahrens.
    Keywords: ddc:510
    Language: English
    Type: masterthesis , doc-type:masterThesis
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  • 12
    Publication Date: 2020-08-05
    Description: This paper describes several experiments to explore the options for solving a class of mixed integer nonlinear programming problems that stem from a real-world mine production planning project. The only type of nonlinear constraints in these problems are bilinear equalities involving continuous variables, which enforce the ratios between elements in mixed material streams. A branch-and-bound algorithm to handle the integer variables has been tried in another project. However, this branch-and-bound algorithm is not effective for handling the nonlinear constraints. Therefore state-of-the-art nonlinear solvers are utilized to solve the resulting nonlinear subproblems in this work. The experiments were carried out using the NEOS server for optimization. After finding that current nonlinear programming solvers seem to lack suitable preprocessing capabilities, we preprocess the instances beforehand and use an heuristic approach to solve the nonlinear subproblems. In the appendix, we explain how to add a polynomial constraint handler that uses IPOPT as embedded nonlinear programming solver for the constraint programming framework SCIP. This is one of the crucial steps for implementing our algorithm in SCIP. We briefly described our approach and give an idea of the work involved.
    Keywords: ddc:510
    Language: English
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  • 13
    Publication Date: 2020-08-05
    Description: Dieser kurze Aufsatz zur Algorithmengeschichte ist Eberhard Knobloch, meinem Lieblings-Mathematikhistoriker, zum 65. Geburtstag gewidmet. Eberhard Knobloch hat immer, wenn ich ihm eine historische Frage zur Mathematik stellte, eine Antwort gewusst – fast immer auch sofort. Erst als ich mich selbst ein wenig und dazu amateurhaft mit Mathematikgeschichte beschäftigte, wurde mir bewusst, wie schwierig dieses „Geschäft“ ist. Man muss nicht nur mehrere (alte) Sprachen beherrschen, sondern auch die wissenschaftliche Bedeutung von Begriffen und Symbolen in früheren Zeiten kennen. Man muss zusätzlich herausfinden, was zur Zeit der Entstehung der Texte „allgemeines Wissen“ war, insbesondere, was seinerzeit gültige Beweisideen und -schritte waren, und daher damals keiner präzisen Definition oder Einführung bedurfte. Es gibt aber noch eine Steigerung des historischen Schwierigkeitsgrades: Algorithmengeschichte. Dies möchte ich in diesem Artikel kurz darlegen in der Hoffnung, dass sich Wissenschaftshistoriker dieses Themas noch intensiver annehmen, als sie das bisher tun. Der Grund ist, dass heute Algorithmen viele Bereiche unserer Alltagswelt steuern und unser tägliches Leben oft von funktionierenden Algorithmen abhängt. Daher wäre eine bessere Kenntnis der Algorithmengeschichte von großem Interesse.
    Keywords: ddc:510
    Language: German
    Type: reportzib , doc-type:preprint
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  • 14
    Publication Date: 2016-06-09
    Description: We consider first order optimality conditions for state constrained optimal control problems. In particular we study the case where the state equation has not enough regularity to admit existence of a Slater point in function space. We overcome this difficulty by a special transformation. Under a density condition we show existence of Lagrange multipliers, which have a representation via measures and additional regularity properties.
    Keywords: ddc:510
    Language: English
    Type: reportzib , doc-type:preprint
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  • 15
    Publication Date: 2016-06-09
    Description: The enormous time lag between fast atomic motion and complex pro- tein folding events makes it almost impossible to compute molecular dy- namics on a high resolution. A common way to tackle this problem is to model the system dynamics as a Markov process. Yet for large molec- ular systems the resulting Markov chains can hardly be handled due to the curse of dimensionality. Coarse graining methods can be used to re- duce the dimension of a Markov chain, but it is still unclear how far the coarse grained Markov chain resembles the original system. In order to answer this question, two different coarse-graining methods were analysed and compared: a classical set-based reduction method and an alternative subspace-based approach, which is based on membership vectors instead of sets. On the basis of a small toy system, it could be shown, that in con- trast to the subset-based approach, the subspace-based reduction method preserves the Markov property as well as the essential dynamics of the original system.
    Keywords: ddc:510
    Language: English
    Type: reportzib , doc-type:preprint
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  • 16
    Publication Date: 2021-02-19
    Description: Line planning is an important step in the strategic planning process of a public transportation system. In this paper, we discuss an optimization model for this problem in order to minimize operation costs while guaranteeing a certain level of quality of service, in terms of available transport capacity. We analyze the problem for path and tree network topologies as well as several categories of line operation that are important for the Quito Trolebus system. It turns out that, from a computational complexity worst case point of view, the problem is hard in all but the most simple variants. In practice, however, instances based on real data from the Trolebus System in Quito can be solved quite well, and significant optimization potentials can be demonstrated.
    Keywords: ddc:510
    Language: English
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  • 17
    Publication Date: 2020-08-05
    Description: It is well known that competitive analysis yields too pessimistic results when applied to the paging problem and it also cannot make a distinction between many paging strategies. Many deterministic paging algorithms achieve the same competitive ratio, ranging from inefficient strategies as flush-when-full to the good performing least-recently-used (LRU). In this paper, we study this fundamental online problem from the viewpoint of stochastic dominance. We show that when sequences are drawn from distributions modelling locality of reference, LRU is stochastically better than any other online paging algorithm.
    Keywords: ddc:510
    Language: English
    Type: reportzib , doc-type:preprint
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  • 18
    Publication Date: 2020-12-15
    Description: Die Angebotsplanung im öffentlichen Nahverkehr umfasst die Aufgaben der Netz-, Linien-,Fahr- und Preisplanung. Wir stellen zwei mathematische Optimierungsmodelle zur Linien- und Preisplanung vor. Wir zeigen anhand von Berechnungen für die Verkehrsbetriebe in Potsdam(ViP), dass sich damit komplexe Zusammenhänge quantitativ analysieren lassen. Auf diese Weise untersuchen wir die Auswirkungen von Freiheitsgraden auf die Konstruktion von Linien und die Wahl von Reisewegen der Passagiere, Abhängigkeiten zwischen Kosten und Reisezeiten sowie den Einfluss verschiedener Preissysteme auf Nachfrage und Kostendeckung.
    Keywords: ddc:510
    Language: German
    Type: reportzib , doc-type:preprint
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  • 19
    Publication Date: 2022-03-14
    Description: This article introduces constraint integer programming (CIP), which is a novel way to combine constraint programming (CP) and mixed integer programming (MIP) methodologies. CIP is a generalization of MIP that supports the notion of general constraints as in CP. This approach is supported by the CIP framework SCIP, which also integrates techniques from SAT solving. SCIP is available in source code and free for non-commercial use. We demonstrate the usefulness of CIP on two tasks. First, we apply the constraint integer programming approach to pure mixed integer programs. Computational experiments show that SCIP is almost competitive to current state-of-the-art commercial MIP solvers. Second, we employ the CIP framework to solve chip design verification problems, which involve some highly non-linear constraint types that are very hard to handle by pure MIP solvers. The CIP approach is very effective here: it can apply the full sophisticated MIP machinery to the linear part of the problem, while dealing with the non-linear constraints by employing constraint programming techniques.
    Keywords: ddc:510
    Language: English
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  • 20
    Publication Date: 2016-06-09
    Description: An extended mathematical framework for barrier methods for state constrained optimal control compared to [Schiela, ZIB-Report 07-07] is considered. This allows to apply the results derived there to more general classes of optimal control problems, in particular to boundary control and finite dimensional control.
    Keywords: ddc:510
    Language: English
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  • 21
    Publication Date: 2021-08-05
    Description: In the recent years there has been tremendous progress in the development of algorithms to find optimal solutions for integer programs. In many applications it is, however, desirable (or even necessary) to generate all feasible solutions. Examples arise in the areas of hardware and software verification and discrete geometry. In this paper, we investigate how to extend branch-and-cut integer programming frameworks to support the generation of all solutions. We propose a method to detect so-called unrestricted subtrees, which allows us to prune the integer program search tree and to collect several solutions simultaneously. We present computational results of this branch-and-count paradigm which show the potential of the unrestricted subtree detection.
    Keywords: ddc:510
    Language: English
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  • 22
    Publication Date: 2020-08-05
    Description: Edmonds showed that the so-called rank inequalities and the nonnegativity constraints provide a complete linear description of the matroid polytope. By essentially adding Grötschel's cardinality forcing inequalities, we obtain a complete linear description of the cardinality constrained matroid polytope which is the convex hull of the incidence vectors of those independent sets that have a feasible cardinality. Moreover, we show how the separation problem for the cardinality forcing inequalities can be reduced to that for the rank inequalities. We also give necessary and sufficient conditions for a cardinality forcing inequality to be facet defining.
    Keywords: ddc:510
    Language: English
    Type: reportzib , doc-type:preprint
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  • 23
    Publication Date: 2020-08-05
    Description: The paper describes a method for solution of very large overdetermined algebraic polynomial systems on an example that appears from a classification of all integrable 3-dimensional scalar discrete quasilinear equations $Q_3=0$ on an elementary cubic cell of the lattice ${\mathbb Z}^3$. The overdetermined polynomial algebraic system that has to be solved is far too large to be formulated. A probing' technique which replaces independent variables by random integers or zero allows to formulate subsets of this system. An automatic alteration of equation formulating steps and equation solving steps leads to an iteration process that solves the computational problem.
    Keywords: ddc:510
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  • 24
    Publication Date: 2020-08-05
    Description: An algorithmic method using conservation law multipliers is introduced that yields necessary and sufficient conditions to find invertible mappings of a given nonlinear PDE to some linear PDE and to construct such a mapping when it exists. Previous methods yielded such conditions from admitted point or contact symmetries of the nonlinear PDE. Through examples, these two linearization approaches are contrasted.
    Keywords: ddc:510
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  • 25
    Publication Date: 2021-02-26
    Description: We classify all integrable 3-dimensional scalar discrete affine linear equations $Q_3=0$ on an elementary cubic cell of the lattice ${\mathbb Z}^3$. An equation $Q_3=0$ %of such form is called integrable if it may be consistently imposed on all $3$-dimensional elementary faces of the lattice ${\mathbb Z}^4$. Under the natural requirement of invariance of the equation under the action of the complete group of symmetries of the cube we prove that the only ontrivial(non-linearizable) integrable equation from this class is the well-known dBKP-system.
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  • 26
    Publication Date: 2020-12-11
    Description: The article describes the online mathematics test {\tt http://lie.math.brocku.ca/mathtest}, its typical applications and experiences gathered.
    Keywords: ddc:510
    Language: English
    Type: reportzib , doc-type:preprint
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  • 27
    Publication Date: 2020-08-05
    Description: We introduce (TTPlib), a data library for train timetabling problems that can be accessed at http://ttplib.zib.de. In version 1.0, the library contains data related to 50 scenarios. Most instances result from the combination of macroscopic railway networks and several train request sets for the German long distance area containing Hannover, Kassel and Fulda, short denoted by Ha-Ka-Fu. In this paper, we introduce the data concepts of TTPlib, describe the scenarios included in the library and provide a free visualization tool TraVis.
    Keywords: ddc:510
    Language: English
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  • 28
    Publication Date: 2020-08-05
    Description: The purpose of this paper is twofold. An immediate practical use of the presented algorithm is its applicability to the parametric solution of underdetermined linear ordinary differential equations (ODEs) with coefficients that are arbitrary analytic functions in the independent variable. A second conceptual aim is to present an algorithm that is in some sense dual to the fundamental Euclids algorithm, and thus an alternative to the special case of a Gr\"{o}bner basis algorithm as it is used for solving linear ODE-systems. In the paper Euclids algorithm and the new dual version' are compared and their complementary strengths are analysed on the task of solving underdetermined ODEs. An implementation of the described algorithm is interactively accessible at http://lie.math.brocku.ca/crack/uode.
    Keywords: ddc:510
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  • 29
    Publication Date: 2020-08-05
    Description: This paper proposes a new method for probabilistic analysis of online algorithms that is based on the notion of stochastic dominance. We develop the method for the Online Bin Coloring problem introduced by Krumke et al. Using methods for the stochastic comparison of Markov chains we establish the strong result that the performance of the online algorithm GreedyFit is stochastically dominated by the performance of the algorithm OneBin for any number of items processed. This result gives a more realistic picture than competitive analysis and explains the behavior observed in simulations.
    Keywords: ddc:510
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  • 30
    Publication Date: 2020-12-15
    Description: The optimization of fare systems in public transit allows to pursue objectives such as the maximization of demand, revenue, profit, or social welfare. We propose a non-linear optimization approach to fare planning that is based on a detailed discrete choice model of user behavior. The approach allows to analyze different fare structures, optimization objectives, and operational scenarios involving, e.g., subsidies. We use the resulting models to compute optimized fare systems for the city of Potsdam, Germany.
    Keywords: ddc:510
    Language: English
    Type: reportzib , doc-type:preprint
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  • 31
    Publication Date: 2022-03-14
    Description: Pseudo-Boolean problems generalize SAT problems by allowing linear constraints and a linear objective function. Different solvers, mainly having their roots in the SAT domain, have been proposed and compared,for instance, in Pseudo-Boolean evaluations. One can also formulate Pseudo-Boolean models as integer programming models. That is,Pseudo-Boolean problems lie on the border between the SAT domain and the integer programming field. In this paper, we approach Pseudo-Boolean problems from the integer programming side. We introduce the framework SCIP that implements constraint integer programming techniques. It integrates methods from constraint programming, integer programming, and SAT-solving: the solution of linear programming relaxations, propagation of linear as well as nonlinear constraints, and conflict analysis. We argue that this approach is suitable for Pseudo-Boolean instances containing general linear constraints, while it is less efficient for pure SAT problems. We present extensive computational experiments on the test set used for the Pseudo-Boolean evaluation 2007. We show that our approach is very efficient for optimization instances and competitive for feasibility problems. For the nonlinear parts, we also investigate the influence of linear programming relaxations and propagation methods on the performance. It turns out that both techniques are helpful for obtaining an efficient solution method.
    Keywords: ddc:510
    Language: English
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  • 32
    Publication Date: 2020-08-05
    Description: Millionen von Menschen werden allein in Deutschland täglich von Bussen, Bahnen und Flugzeugen transportiert. Der öffentliche Personenverkehr (ÖV) ist von großer Bedeutung für die Lebensqualität einzelner aber auch für die Leistungsfähigkeit ganzer Regionen. Qualität und Effizienz von ÖV-Systemen hängen ab von politischen Rahmenbedingungen (staatlich geplant, wettbewerblich organisiert) und der Eignung der Infrastruktur (Schienensysteme, Flughafenstandorte), vom vorhandenen Verkehrsangebot (Fahr- und Flugplan), von der Verwendung angemessener Technologien (Informations-, Kontroll- und Buchungssysteme) und dem bestmöglichen Einsatz der Betriebsmittel (Energie, Fahrzeuge und Personal). Die hierbei auftretenden Entscheidungs-, Planungs- und Optimierungsprobleme sind z.T. gigantisch und "schreien" aufgrund ihrer hohen Komplexität nach Unterstützung durch Mathematik. Dieser Artikel skizziert den Stand und die Bedeutung des Einsatzes von Mathematik bei der Planung und Durchführung von öffentlichem Personenverkehr, beschreibt die bestehenden Herausforderungen und regt zukunftsweisende Maßnahmen an.
    Keywords: ddc:510
    Language: German
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  • 33
    Publication Date: 2019-05-10
    Description: Pulse thermography of concrete structures is used in civil engineering for detecting voids, honeycombing and delamination. The physical situation is readily modeled by Fourier's law. Despite the simplicity of the PDE structure, quantitatively realistic numerical 3D simulation faces two major obstacles. First, the short heating pulse induces a thin boundary layer at the heated surface which encapsulates all information and therefore has to be resolved faithfully. Even with adaptive mesh refinement techniques, obtaining useful accuracies requires an unsatisfactorily fine discretization. Second, bulk material parameters and boundary conditions are barely known exactly. We address both issues by a semi-analytic reformulation of the heat transport problem and by parameter identification. Numerical results are compared with measurements of test specimens.
    Keywords: ddc:510
    Language: English
    Type: reportzib , doc-type:preprint
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  • 34
    Publication Date: 2016-06-09
    Description: In this paper we are concerned with the application of interior point methods in function space to gradient constrained optimal control problems, governed by partial differential equations. We will derive existence of solutions together with first order optimality conditions. Afterwards we show continuity of the central path, together with convergence rates depending on the interior point parameter.
    Keywords: ddc:510
    Language: English
    Type: reportzib , doc-type:preprint
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  • 35
    Publication Date: 2016-06-09
    Description: We consider an interior point method in function space for PDE constrained optimal control problems with state constraints. Our emphasis is on the construction and analysis of an algorithm that integrates a Newton path-following method with adaptive grid refinement. This is done in the framework of inexact Newton methods in function space, where the discretization error of each Newton step is controlled by adaptive grid refinement in the innermost loop. This allows to perform most of the required Newton steps on coarse grids, such that the overall computational time is dominated by the last few steps. For this purpose we propose an a-posteriori error estimator for a problem suited norm.
    Keywords: ddc:510
    Language: English
    Type: reportzib , doc-type:preprint
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  • 36
    Publication Date: 2020-08-05
    Description: Ticket pricing in public transport usually takes a welfare or mnemonics maximization point of view. These approaches do not consider fairness in the sense that users of a shared infrastructure should pay for the costs that they generate. We propose an ansatz to determine fair ticket prices that combines concepts from cooperative game theory and integer programming. An application to pricing railway tickets for the intercity network of the Netherlands demonstrates that, in this sense, prices that are much fairer than standard ones can be computed in this way.
    Keywords: ddc:510
    Language: English
    Type: reportzib , doc-type:preprint
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  • 37
    Publication Date: 2014-02-26
    Description: We present a second order sharp interface finite volume method for the solution of the three-dimensional poisson equation with variable coefficients on Cartesian grids. In particular, we focus on interface problems with discontinuities in the coefficient, the source term, the solution, and the fluxes across the interface. The method uses standard piecewiese trilinear finite elements for normal cells and a double piecewise trilinear ansatz for the solution on cells intersected by the interface resulting always in a compact 27-point stencil. Singularities associated with vanishing partial volumes of intersected grid cells are removed by a two-term asymptotic approach. In contrast to the 2D method presented by two of the authors in [M.~Oevermann, R.~Klein: A Cartesian grid finite volume method for elliptic equations with variable coefficients and embedded interfaces, J.~Comp.~Phys.~219 (2006)] we use a minimization technique to determine the unknown coefficients of the double trilinear ansatz. This simplifies the treatment of the different cut-cell types and avoids additional special operations for degenerated interface topologies. The resulting set of linear equations has been solved with a BiCGSTAB solver preconditioned with an algebraic multigrid. In various testcases -- including large coefficient ratios and non-smooth interfaces -- the method achieves second order of accuracy in the L_inf and L_2 norm.
    Keywords: ddc:510
    Language: English
    Type: reportzib , doc-type:preprint
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  • 38
    Publication Date: 2020-08-05
    Description: Given a combinatorial optimization problem and a subset $N$ of natural numbers, we obtain a cardinality constrained version of this problem by permitting only those feasible solutions whose cardinalities are elements of $N$. In this paper we briefly touch on questions that addresses common grounds and differences of the complexity of a combinatorial optimization problem and its cardinality constrained version. Afterwards we focus on polytopes associated with cardinality constrained combinatorial optimization problems. Given an integer programming formulation for a combinatorial optimization problem, by essentially adding Grötschel's cardinality forcing inequalities, we obtain an integer programming formulation for its cardinality restricted version. Since the cardinality forcing inequalities in their original form are mostly not facet defining for the associated polyhedra, we discuss possibilities to strengthen them.
    Keywords: ddc:510
    Language: English
    Type: reportzib , doc-type:preprint
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  • 39
    Publication Date: 2020-08-05
    Description: This survey concerns optimization problems arising in the design of survivable communication networks. It turns out that such problems can be modeled in a natural way as non-compact linear programming formulations based on multicommodity flow network models. These non-compact formulations involve an exponential number of path flow variables, and therefore require column generation to be solved to optimality. We consider several path-based survivability mechanisms and present results, both known and new, on the complexity of the corresponding column generation problems (called the pricing problems). We discuss results for the case of the single link (or node) failures scenarios, and extend the considerations to multiple link failures. Further, we classify the design problems corresponding to different survivability mechanisms according to the structure of their pricing problem. Finally, we show that almost all encountered pricing problems are hard to solve for scenarios admitting multiple failures.
    Keywords: ddc:510
    Language: English
    Type: reportzib , doc-type:preprint
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  • 40
    Publication Date: 2021-02-19
    Description: We introduce an optimization model for the line planning problem in a public transportation system that aims at minimizing operational costs while ensuring a given level of quality of service in terms of available transport capacity. We discuss the computational complexity of the model for tree network topologies and line structures that arise in a real-world application at the Trolebus Integrated System in Quito. Computational results for this system are reported.
    Keywords: ddc:510
    Language: English
    Type: reportzib , doc-type:preprint
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  • 41
    Publication Date: 2021-02-19
    Description: Line planning is an important step in the strategic planning process of a public transportation system. In this paper, we discuss an optimization model for this problem in order to minimize operation costs while guaranteeing a certain level of quality of service, in terms of available transport capacity. We analyze the problem for path and tree network topologies as well as several categories of line operation that are important for the Quito Trolebus system. It turns out that, from a computational complexity worst case point of view, the problem is hard in all but the most simple variants. In practice, however, instances based on real data from the Trolebus System in Quito can be solved quite well, and significant optimization potentials can be demonstrated.
    Keywords: ddc:510
    Language: English
    Type: reportzib , doc-type:preprint
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  • 42
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 43
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 21-30 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Diastereomers of Nonactin Acid and Epimers of 2-Desmethylnonactin AcidNonactin acid 8a was prepared in only four reaction steps starting from the furan 3a. - In an attempt to prepare nonactin acid by intramolecular cyclisation of 13, the tetrahydropyran 15 was obtained in addition to the desired tetrahydrofuran 14. Treatment of 14 + 15 with sodium cyanide under the conditions of the Kolbe reaction led to the formation of the isomeric acids 16 + 17.
    Notes: Ausgehend von dem Furan 3a gelangt man in vier Reaktionsschritten zur Nonactinsäure 8a, einem 2.5-disubstituierten Tetrahydrofuran. - Beim Versuch der Darstellung von Nonactinsäure durch intramolekulare Cyclisierung von 13 entstand neben dem gewünschten Tetrahydrofuran 14 durch Ringerweiterung auch das Tetrahydropyran 15. Die Umwandlung von 14 + 15 mit Natriumcyanid nach Kolbe führte zu den stellungsisomeren Säuren 16 + 17.
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  • 44
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 40-49 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Aromatic Solvent Induced Shifts (ASIS) in the N.M.R. Spectra of tert-Butyl-, tert-Butoxy-and Nitro(tert-butyl)benzene DerivativesThe n.m.r. spectra of aromatic tert-butyl and tert-butoxy groups which are not separated in CCl4 may always be resolved in benzene and pyridine solution. In some cases (e. g. 15) assignements for these signals are obtained empirically from their solvent shifts. The signals of the aromatic protons in 2.6- and 3.4-dinitro-1-tert-butylbenzene show remarkable solvent effects (CCl4→C6D6) which cannot be explained by the 1:1 complex models. The shifts induced by aromatic solvents must originate rather from the time average over all orientations of the anisotropic molecules in the nearest solvent schell. The interpretation of such solvent shifts should be based on values derived from an absolute standard.
    Notes: In CCl4 nicht getrennte NMR-Signale für aromatisch gebundene tert.-Butyl- und tert.-Butyloxygruppen werden in Benzol und Pyridin stets aufgelöst und können in bestimmten Fällen (z. B. 15) an Hand der Lösungsmittelabhängigkeit empirisch zugeordnet werden. Die Ringprotonensignale bei 2.6- und 3.4-Dinitro-1-tert.-butyl-benzol zeigen beim Lösungsmittelwechsel CCl4→C6D6 sehr unterschiedliche und z. T. sehr starke Verschiebungen, die nicht mit dem Modell spezifischer 1:1-Komplexe erklärt werden können. Die Wirkung des aromatischen Lösungsmittels muß vielmehr durch das Zeitmittel über alle Orientierungen aller anisotroper Moleküle in der engsten Solvathülle zustandekommen. Auf die Verwendung eines absoluten Standards bei der Deutung von Lösungsmitteleffekten in der NMR-Spektroskopie wird hingewiesen.
    Additional Material: 2 Tab.
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  • 45
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 473-478 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of 7-β-Neohesperidosyl-4′-(β-D-glucopyranosyl)naringenin, a Flavanone Triglycoside from Citrus FruitsThe glycoside 7-β-neohesperidosyl-4′-(β-D-glucopyranosyl)naringenin (3), isolated from the segments of Citrus paradisi Macf, by Mizelle et al., was synthesized by condensation of phloracetophenone 4-β-neohesperidoside (1) with 4-hydroxybenzaldehyde 4-β-D-glucopyranoside (2) and by cyclisation of the resulting chalkone glykoside. Dehydrogenation of the flavanone triglykoside undecaacetate and subsequent saponification leads to the formation of 7-β-neohesperidosyl-4′-(β-D-glucopyranosyl)apigenin (7), the first synthetic apigenin triglycoside.
    Notes: Das von Mizelle und Mitarbb. aus Citrus paradisi Macf. isolierte 7-β-Neohesperidosyl-4′-β-D-glucopyranosyl-naringenin (3) wurde durch Kondensation von Phloracetophenon-4-β-neohesperidosid (1) mit 4-Hydroxy-benzaldehyd-4-β-D-glucopyranosid (2) und Cyclisierung des entstandenen Chalkonglykosids synthetisiert. Durch Dehydrierung des Flavanontriglykosid-undecaacetats (3a) wurde nach Verseifen das 7-β-Neohesperidosyl-4′-β-D-glucopyranosyl-apigenin (7) als erstes synthetisches Apigenintriglykosid dargestellt.
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  • 46
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Theoretical and Spectroscopic Investigations of Indigo Dyes, XI. Compounds with the Basic Chromophore of Thioindigo: Preparation and Properties of 3.4-Bis(alkylthio)hex-3-ene-2.5-dionesThe nucleophilic exchange of halogen in trans-3.4-dibromo- and -3.4-dichlorohex-3-ene-2.5-dione (4 and 5) with alkanethiols is studied. With bromine as leaving group substitution and reductive debromination leads to the formation of trans-3-methylthiohex-3-ene-2.5-dione (7a). With chlorine the expected trans-3.4-bis(alkylthio)hex-3-ene-2.5-diones (6a-c) are formed. These have the same structure and geometry as the basic chromophore of thioindigo, but they do not show the corresponding typical chemical and spectroscopic properties. They rather behave spectroscopically like β-alkylthio-α,β-unsaturated ketones. Conformation and spectroscopic properties of 6a-e are discussed with respect to the sterical requirements of the different groups at the sulfur atoms.
    Notes: Der Austausch der beiden Halogenatome von trans-3.4-Dibrom- und -3.4-Dichlor-hexen-(3)-dion-(2.5) (4 und 5) gegen Alkylmercaptane wird untersucht. Mit Brom als Abgangsgruppe erfolgt neben einfachem Austausch quantitativ eine reduktive Entbromierung zu trans-3-Methylmercapto-hexen-(3)-dion-(2.5) (7a), während mit Chlor als Abgangsgruppe zweifacher Austausch zu trans-3.4-Bis-alkylmercapto-hexen-(3)-dionen-(2.5) (6a-e) stattfindet. Diese zeigen nicht die spektroskopischen und chemischen Eigenschaften, die man für dieses - in der Verknüpfung ihrer funktionellen Gruppen dem Thioindigogrundchromophor entsprechende - System erwartet, sondern sie verhalten sich wie einfache β-alkylmercapto-α,β-ungesättigte Ketone. Die Abhängigkeit der Konformation und der spektroskopischen Eigenschaften von der Größe der Alkylreste am Schwefel wird diskutiert.
    Additional Material: 4 Ill.
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  • 47
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 549-557 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Boron, LIV. Chemical Properties of Tris(2.2-dimethylhydrazino)boraneIn contrast to the ready cleavage of BN-bonds in tris(dialkylamino)boranes by BCl3, (BH3)2, HCl or CH3J the prefered reactions of these acids with tris(2.2-dimethylhydrazino)borane (1) are additions. Due to the greater basicity of the dimethylamino group as compared to the NH moiety, additions occur at the group (CH3)2N before the group NH is attacked. Solvolysis of B[NH—N(CH3)2]3 (1) by H2O or C2H5OH yields (CH3)2 N—NH2 and B(OH)3 or B(OC2H5)3, respectively, but no mixed compounds XnB[NH—N(CH3)2]3 n are formed in these reactions or by ligand exchange with B(OCH3)3 or B[N(CH3)2]3. 1 is stable up to 280° at higher temperature condensation with formation of N.N-dimethylhydrazine occurs.
    Notes: Während die Verbindungen BCl3, (BH3)2, HCl und CH3J die B N-Bindungen von Tris(dialkylamino)-boranen spalten, lagern sie sich an Tris(2.2-dimethyl-hydrazino)-boran (1) an. Dabei erfolgt zunächst Addition an die stärker basische Dimethylaminogruppe, danach reagiert auch die schwächer basische NH-Gruppe. Solvolysen von 1 mit H2O und C2H5OH oder Komproportionierungen mit B(OCH3)3 oder B[N(CH3)2]3 führen nicht zu gemischten Verbindungen XnB[NH—N(CH3)2]3 n(X—OH, OR, N(CH3)2). Im Vergleich zu Tris(alkylamino)-boranen ist 1 thermisch sehr stabil. Erst oberhalb 280° spaltet sich N,N-Dimethylhydrazin ab.
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  • 48
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 605-638 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: o- and p-(Dicyanomethylene)quinocyclopropenes. Synthesis, Mechanisms of Formation and Propertieso- and p-quinocyclopropenes of the benzene, naphthalene, anthracene, phenanthrene, and fluorene series (9, 12-15, 29, 30b, 37, 38) are prepared a) by thermolysis of 1:1 adducts of 3-ethoxy-1.2-diaryl-cyclopropenylium cations 6 and arylmalodinitrile anions, b) by reaction of diarylcyclopropenones with arylmalodinitriles in acetic anhydride. The reaction mechanisms suggested by isolation of intermediates are discussed. - Polarography of the quinocyclopropenes shows reversible formation of a radical cation in a one-electron step. This is in agreement with calculations according to the simple HMO model, which give satisfactory correlations with polarography, u. v. and i. r. spectroscopical data.
    Notes: o- und p-Chinocyclopropene der Benzol-, Naphthalin-, Anthracen-, Phenanthren- und Fluorenreihe (9, 12-15, 29, 30b, 37, 38) werden dargestellt a) durch Thermolyse von 1:1-Addukten aus 3-Äthoxy-1.2-diaryl-cyclopropenylium-Kationen 6 und Arylmalodinitril-Anionen, b) durch Reaktion von Diarylcyclopropenonen und Arylmalodinitrilen in Acetanhydrid. Die sich aus der Isolierung von Zwischenprodukten ergebenden Reaktionsmechanismen werden diskutiert. - Durch polarographische Untersuchungen wird festgestellt, daß die Chinocyclopropene reversibel im Einelektronenschritt in ein Radikal-Kation übergehen. Dies wird durch Rechnungen nach dem einfachen HMO-Modell bestätigt, die befriedigende Korrelationen mit den polarographischen sowie UV- und IR-spektroskopischen Daten ergeben.
    Additional Material: 5 Ill.
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  • 49
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 665-667 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 50
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 668-670 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 51
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 71-74 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies on the Bromination of Hydrocarbons in Liquid BromineThe bromination of aliphatic hydrocarbons in liquid bromine in the presence of catalytic amounts of hydrobromic acid is described. Hydrocarbons with neighbouring tertiary carbon atoms and tetraalkylated ethylenes give definite bromination products. From the corresponding hydrocarbons were obtained 1.4-Dibromo-2.3-bis(bromomethyl)but-2-ene (1), 1.4.5-Tribromo-2.3-bis(bromomethyl)pent-2-ene (2), 1.4.5-Tribromo-2.3-bis(bromomethyl)-hex-2-ene (3), 1.4.5-Tribromo-2-bromomethyl-3-(α.β-dibromoethyl)pent-2-ene (4), and 1.4.5.8-Tetrabromo-Δ4a(8a)-octalin (5).
    Notes: Bei der Bromierung in flüssigem Brom in Gegenwart katalytischer Mengen Bromwasserstoffsäure bilden aliphatische Kohlenwasserstoffe mit benachbarten tertiären Kohlenstoffatomen und tetraalkylierte Äthylene definierte Bromierungsprodukte. Im einzelnen werden 1.4-Dibrom-2.3-bis-brommethyl-buten-(2) (1), 1.4.5-Tribrom-2.3-bis-brommethyl-penten-(2) (2), 1.4.5-Tribrom-2.3-bis-brommethyl-hexen-(2) (3), 1.4.5-Tribrom-2-brommethyl-3-[α.β-dibromäthyl]-penten-(2) (4) und 1.4.5.8-Tetrabrom-Δ4a(8a)-octalin (5) aus den entsprechenden Kohlenwasserstoffen erhalten.
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  • 52
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 110-130 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Complex Chemistry of Four-Centre π-Systems, III. Colour, Solvatochromy and Reduction Potentials of (1.4-Diazabutadiene)molybdenum TetracarbonylsMolybdenum tetracarbonyl complexes of the =N=C=C=N-system (1,4-diazabutadiene=DAB) show an intense, low energy electronic transition, which is antiparallel to the ground state dipole moment; its solvent dependance is measured for 33 mostly new compounds and shows directly the amount of metal-ligand interaction, and thus of π-backbonding. The π-delocalisation of metal-D-electrons strongly depends on the substituents of the DAB-system, but the complex ground state has still molybdenum in the valence state 0. The competing mesomeric, inductiv and steric effects of the DAB ligands can be separated, too, by polarographic reduction potentials of complexes and ligands. The results can be understood in terms of simple perturbation theory.
    Notes: Molybdäncarbonyl-Komplexe des =N=C=C=N-Systems (1.4-Diaza-butadien=DAB) zeigen eine antiparallel zum Grundzustandsdipolmoment gerichtete intensive farbgebende Elektronenanregung, deren an dreiunddreißig meist neuen Verbindungen untersuchte Solvatochromie direkte Aussagen über die Größe der Metall-Ligand-Termwechselwirkung und damit über die π-Rück bindung gestattet. Die Delokalisierung der Metall-D-Elektronen ist abhängig von den Substituenten des DAB-Systems, der Komplexgrundzustand enthält aber formal 0-wertiges Molybdän. Die konkurrierenden induktiven, mesomeren und sterischen Effekte der DAB-Liganden sind in den polarographischen Reduktionspotentialen der Komplexe und Liganden selbst ebenfalls genau abgrenzbar, bestätigen die Solvatochromie-untersuchungen und lassen sich im Rahmen einfacher Störungstheorie widerspruchsfrei deuten.
    Additional Material: 7 Ill.
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  • 53
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 138-144 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reductive Silylation of NaphthaleneThe reaction of naphthalene with trimethylchlorosilane and sodium has been found to afford 1.4-bis(trimethylsilyl)-1.4-dihydro- and 1.2-bis(trimethylsilyl)-1.2-dihydronaphthalene (1, 2), whereas potassium reacts to give mainly 1.2.3.7-tetrakis(trimethylsilyl)-1.2.3.4-tetrahydro-naphthalene (3) besides 1.2.4-tris(trimethylsilyl)-1.4-dihydro-(4) and 1.2.4-tris(trimethylsilyl)-1.2-dihydronaphthalene (5). The configuration has been determined by n.m.r. spectroscopy.
    Notes: Bei der reduktiven Silylierung von Naphthalin mit Natrium und Trimethylchlorsilan werden vorwiegend nur 1.4-Bis-trimethylsilyl-1.4-dihydro- und 1.2-Bis-trimethylsilyl-1.2-dihydronaphthalin (1, 2) gebildet. Ersetzt man jedoch das Natrium durch Kalium, so erhält man 1.2.4-Tris-trimethylsilyl-1.4-dihydro- (4) sowie 1.2.4-Tris-trimethylsilyl-1.2-dihydro-naphthalin (5) und vor allem 1.2.3.7-Tetrakis-trimethylsilyl-1.2.3.4-tetrahydro-naphthalin (3). - Die Aufklärung der Konfiguration erfolgte NMR-spektroskopisch.
    Additional Material: 2 Tab.
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  • 54
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 168-172 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Properties of 4-Chloro- and 4-Bromo-2H-chromenes and of 3-Bromo-2H-chromenesDehydrobromination of trans-3,4-dihalochromans yields the 4-halo-2H-chromenes 1-4. Dehydration of cis-3-bromo-4-hydroxychromans leads to the 3-bromo-2H-chromenes 5 and 6.
    Notes: Durch Abspaltung von Bromwasserstoff entstehen aus den trans-3.4-Dihalogen-chromanen die entsprechenden 4-Halogen-2H-chromene 1-4. Die 3-Brom-2H-chromene 5 und 6 erhält man durch Dehydratisierung der cis-3-Brom-4-hydroxy-chromane.
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  • 55
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 210-219 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Vinylogous Acyl Compounds, IX. Hydrolysis of Vinylogous Carbonamidium SaltsThe hydrolysis of vinylogous carbonamidium salts 10 in aqueous sodium hydrogen carbonate solution does not lead - as hitherto supposed - to meso-(2-acylvinyl)acylacetaldehydes 8, but to bis(2-acylvinyl)ethers 11. The structure of these compounds results from n. m. r. and i. r. spectra and is confirmed by independent synthesis.
    Notes: Die Hydrolyse vinyloger Carbonamidiumsalze 10 in wäßriger Natriumhydrogencarbonat-Lösung führt nicht - wie bisher angenommen - zu meso-[2-Acyl-vinyl]-acylacetaldehyden 8, sondern zu Bis-[2-acyl-vinyl]-äthern 11. Die Strukturzuordnung dieser Verbindungen gründet sich auf NMR- und IR-spektroskopische Befunde sowie auf eine unabhängige synthese.
    Additional Material: 3 Tab.
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  • 56
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 160-167 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1.2.3-Tricarbonyl Compounds, V. Hydrate-forming 1.2.3-Tricarbonyl Compounds as Dienophiles in Diels-Alder ReactionsThe 1.2.3-tricarbonyl compounds 5-8 react as dienophiles and add isoprene or 2.3-dimethylbuta-1.3-diene to yield the spiro-dihydropyranes 9-16. I.r., mass, and n.m.r. spectra are discussed.
    Notes: Cyclische 1.2.3-Tricarbonylverbindungen (vgl. 5-8) reagieren als Dienophile mit Isopren und 2.3-Dimethyl-butadien-(1.3) unter Bildung der Spiro-dihydropyrane 9-16. Die IR- und Massenspektren der Reaktionsprodukte sowie die NMR-Spektren von 9 und 10 werden diskutiert.
    Additional Material: 2 Tab.
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  • 57
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 205-209 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Microbiological 11β-Hydroxylation of 3β-Hydroxy-5α.6α-epoxysteroidsSome 3β-Hydroxy-5α,6α-epoxysteroids are hydroxylated specifically in 11β-position without formation of by-products by the fungus Curvularia lunata.
    Notes: Eine Reihe von 3β-Hydroxy-5α.6α-epoxy-steroiden wird mit dem Pilz Curvularia lunata ohne Bildung von Nebenprodukten spezifisch in 11β-Stellung hydroxyliert.
    Additional Material: 1 Tab.
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  • 58
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 248-258 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Isoquinolines, II. 3.3-Dialkyl-3.4-dihydroisoquinolines from Alkyl-aryl-cyclopropanesUnder the conditions of the Graf-Ritter reaction alkyl-aryl-cyclopropanes 8 react with nitriles 2 via dialkyl-benzyl-carbonium ions 1 to give 3.3-dialkyl-3.4-dihydroisoquinolines 3. The effect of the substituents R1, R2, and R3 in 8 on the reaction is discussed.
    Notes: Alkyl-aryl-cyclopropane 8 reagieren unter den Bedingungen der Graf-Ritter-Reaktion über Dialkyl-benzyl-carboniumionen 1 mit Nitrilen 2 zu 3.3-dialkylsubstituierten 3.4-Dihydroisochinolinen 3. Der Einfluß der Substituenten R1, R2 und R3 in 8 auf den Reaktionsverlauf wird besprochen.
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  • 59
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 270-278 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses of Aromatic Erythrina-Alkaloids, XVIII. Concerning the Existence of trans-ErythrinanesWolff-Kishner reduction of the 6α-bromo-ketolactam 2 affords, among other products, the 6β-hydroxyerythrinane-8-one 8. This is the first compound of the trans-erythrinane series.
    Notes: Bei der Wolff-Kishner-Reduktion des 6α-Brom-ketolactams 2 entsteht neben anderen Produkten auch das 6β-Hydroxy-erythrinanon-(8) 8, der erste Vertreter der trans-Erythrinan-Reihe.
    Additional Material: 3 Tab.
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  • 60
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 320-332 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Ionization of Organomagnesium Compounds, IV. Formation of Carbanions from Organomagnesium Compounds by Means of Hexamethyl-phosphortriamideStepwise addition of hexamethylphosphortriamide (HMPT) to the solutions of benzyl-like organomagnesium compounds in diethylether results in drastic changes which can be observed spectroscopically. First, the absorption maxima are shifted to longer wave lengths in an apparently continuous manner, until two equivalents of the strongly donating cosolvent have been added. Further addition of HMPT leads to ionization of the C—Mg-bonds. This can be seen from the development of new bands characteristic of the carbanions, as represented by the alkali metal derivatives.
    Notes: Der Zusatz von Hexamethylphosphorsäuretriamid (HMPT) zu den ätherischen Lösungen von benzylartigen Organomagnesium-Verbindungen führt zu drastischen, spektral beobachtbaren Veränderungen. Zunächst tritt eine scheinbar kontinuierliche Verschiebung der Absorptionsmaxima nach längeren Wellen ein, bis zwei Äquivalente des starken Donor-Solvens zugesetzt sind. Weitere Zugabe von HMPT führt zur Ionisation der C—Mg-Bindungen und Freisetzung der betreffenden Carbanionen, die sich durch das Aufkommen der (von den Alkalimetall-Verbindungen bekannten) Carbanion-Banden zu erkennen gibt.
    Additional Material: 4 Ill.
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  • 61
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 343-343 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 62
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 350-351 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 63
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 391-401 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Photochemistry of Small Rings, 23. Carbenacyclopentadienes and Alkynes. - Photochemical Synthesis of Benzindenes and SpirocyclopropenesPhotolysis of phenyl-substituted diazocyclopentadienes 3 in alkynes leads via the intermediate carbenacyclopentadienes to the formation of 1H-benz[e]indenes 5. 5c was degraded to the known compound 3-phenyl-2.3-dihydro-1H-benz[e]indene (8). - On irradiation 3a, f in dimethyl acetylenedicarboxylate yield the spiro[2.4]heptatrienes 9 instead of 5. 9a was rearranged by further irradiation to the benz[e]indene 5f. - The mechanism of the benzindene formation is discussed.
    Notes: Die Photolyse phenyl-substituierter Diazo-cyclopentadiene 3 in Alkinen führt über die Carbena-cyclopentadiene zu 1H-Benz[e]indenen 5. 5c wurde zum bekannten 3-Phenyl-2.3-dihydro-1H-benz[e]inden (8) abgebaut. - Die Bestrahlung von 3a, f in Acetylendicarbonester ergab jedoch nicht 5, sondern die Spiro[2.4]heptatriene 9. 9a wird durch weitere Belichtung in das Benz[e]inden 5f umgelagert. - Der Mechanismus der Benzinden-Bildung wird diskutiert.
    Additional Material: 2 Tab.
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  • 64
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 421-428 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Michael Additions with Ethyl β-Arylacrylates: The Synthesis of 3-Aryl-2.2-bis(ethoxycarbonyl)-5-pyrrolidonesThe Michael reaction of ethyl β-arylacrylates with diethyl acetaminomalonate followed by cyclisation directly yielded the 3-aryl-2.2-bis(ethoxycarbonyl)-5-pyrrolidones (4).
    Notes: β-Aryl-acrylsäure-äthylester werden mit Acetamino-malonsäure-diäthylester nach Michael unter nachfolgender Cyclisierung direkt zu 3-Aryl-2.2-bis-äthoxycarbonyl-pyrrolidonen-(5) (4) umgesetzt.
    Additional Material: 3 Tab.
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  • 65
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 461-472 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transition Metal Chalcogen Compounds Diphenyldithiophosphinato Complexes of Vanadium(III), Vanadium(IV) and Molybdenum(VI)The preparation and properties of the compounds [(C6H5)2PS2]2MoO2 (3), [(C6H5)2PS2]2-VO (4) and [(C6H5)2PS2]3 V (5) are described. Their vibrational and electronic spectra are reported. The parameters 10 Dq = 13 200/cm and B = 395/cm were calculated from the electronic spectrum of the vanadium(III) compound.
    Notes: Die Darstellung und Eigenschaften der Verbindungen [(C6H5)2PS2]2MoO2 (3), [(C6H5)2PS2]2-VO (4) und [(C6H5)2PS2]3 V (5) werden beschrieben. Die Schwingungs- und Elektronenspektren werden mitgeteilt und letztere mit der Kristallfeldtheorie interpretiert. Für die Vanadin(III)-Verbindung lassen sich aus den Übergängen ν1(3T1g→3T2g) und ν2(3T1g(F) → 3T1g(P)) die Werte für 10 Dq 13200/cm und B 395/cm berechnen.
    Additional Material: 5 Ill.
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  • 66
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 513-518 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Reaction of Boron-Nitrogen Compounds with Excited Carbon Atoms Generated in an ArcThe interaction of carbon vapor from a carbon are with dimethylaminoborane, (CH3)2N—BH2 (1), yields as the main reaction product (dimethylamino)methylborane, (CH3)2 N—BH—CH3 (3), which combines with the starting material to form the four-membered ring compound 5. Other compounds formed in this reaction are (dimethylamino)dimethylborane, (CH3)2N—B(CH3)2 (2), and dimethylaminborane, (CH3)2NH—BH3, as well as the previously unknown compound (CH3)2N—BH—O—BH—N(CH3)2 (6), which could be isolated.
    Notes: Die Reaktion von im Lichtbogen erzeugten Kohlenstoffatomen mit Dimethylaminoboran, (CH3)2N—BH2 (1), ergibt als Hauptreaktionsprodukt das Dimethylamino-methylboran, (CH3)2N—BH—CH3 (3), das sich mit dem Ausgangsmaterial zur Vierringverbindung 5 umsetzt. Weiterhin findet man Dimethylamino-dimethylboran, (CH3)2N—B(CH3)2 (2) und Dimethylamin-boran, (CH3)2NH—BH3. Schließlich kann die bisher noch nicht bekannte Verbindung (CH3)2N—BH—O—BH—N(CH3)2 (6) isoliert werden.
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  • 67
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 528-532 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A Simple Pathway to Azide-Bridged Palladium and Platinum(II) ComplexesSalts of azide-bridged dimeric cations are prepared in quantitative yields by reaction of the monomeric diazido complexes (Ph3P)2 M(N3)2 with nitrosyl- or triethyloxonium salts, and diethyl sulfate, respectively.
    Notes: Salze der azidverbrückten dimeren Kationen entstehen in praktisch quantitativer Ausbeute durch Umsetzung der monomeren Diazidokomplexe (Ph3P)2 M(N3)2 mit Nitrosyl- oder Triäthyloxonium-Salzen bzw. mit Diäthylsulfat.
    Additional Material: 2 Tab.
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  • 68
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 558-576 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Boron, LV. Intramolecular Hydrogen Bonding in (2.2-Dimethylhydrazino)boranesN. m. r. spectroscopic investigations on (2.2-dimethylhydrazino)boranes demonstrate the presence of intramolecular hydrogen bonds in these compounds, and this is further proved by comparison with isopropylaminoboranes. The planar configuration of B[NH—N(CH3)2]3 and B2[NH—N(CH3)2]4 is determined by this bonding. The N—H … N bond energy has been estimated as ∼2.5 kcal/mole from the temperature dependence of the n. m. r. spectra. Intermolecular association is indicated in the compounds R2B—NH—N(CH3)2. - The basicity towards the acid CDCl3 decreases in the isopropylaminoborane series for (2.2-dimethylhydrazino)boranes the series has been found confirming the effects of intramolecular hydrogen bonding.
    Notes: Kernresonanzspektroskopische Untersuchungen an (2.2-Dimethyl-hydrazino)-boranen belegen durch Vergleich mit Isopropylamino-boranen intramolekulare Wasserstoffbrückenbindungen. Diese sind insbesondere für B[NH—N(CH3)2]3 und B2[NH—N(CH3)2]4 konfigurationsbestimmend. Ihre Bindungsenergie beträgt ∼2.5 kcal/Mol. In R2B—NH—N(CH3)2 erfolgt Assoziation über intermolekulare N—H … N-Bindungen, die in Lösung leicht aufbrechen. - Basizitätsbestimmungen mit der Referenzsäure CDCl3 ergeben die Reihe für die Isopropylamino-borane, jedoch für die (2.2-Dimethyl-hydrazino)-borane in Übereinstimmung mit den durch intramolekulare Wasserstoffbrückenbindungen bewirkten Effekten.
    Additional Material: 2 Ill.
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  • 69
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 4-10 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Structure of Thioamides and their Derivatives, XI. N.M.R-Spectroscopic Studies and the Mechanism of Isomerization of Thioamide anionsIn the n. m. r. spectra of thioformamide anions 2 a larger trans long-range coupling constant is observed than in the spectra of the corresponding thioformamides 1. In spite of this spectral evidence indicating that 2 has the stronger partial double bond character, 2 isomerizes faster than 1. This suggests that isomerization proceeds via an inversion mechanism, an assumption which is verified by the steric effects of o-substituents in thioformanilide anions 4. On the other hand, in the case of thioformanilides 3 a rotation mechanism is observed.
    Notes: In den NMR-Spektren von Thioformamid-Anionen 2 wird eine größere trans-Fernkopplungskonstante als in den entsprechenden Thioformamiden 1 gefunden. Trotz des daraus zu folgernden größeren Doppelbindungscharakters wird bei 2 eine schnellere Isomerisierung als bei 1 beobachtet. Der dadurch nahegelegte Inversionsmechanismus wird durch den sterischen Einfluß von o-Substituenten in den Thioformanilid-Anionen 4 belegt, während für die Thioformanilide 3 ein Rotationsmechanismus gefunden wird.
    Additional Material: 3 Tab.
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  • 70
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 50-58 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cycloadditions with Carbodiimides, 1. Influences of Substituents in the Cycloaddition of Ketenes to CarbodiimidesCarbodiimides and ketenes yield 4-imino-2-azetidinones (1-14) in a cycloaddition reaction. Aliphatic carbodiimides show higher reactivity than aromatic carbodiimides. In mixed aliphatic-aromatic substituted carbodiimides, therefore, preferentially one of the C=N bonds undergoes reaction. The structures of the resulting compounds were confirmed by chemical transformations, i.r., and n.m.r. spectra.
    Notes: Carbodiimide gehen mit Ketenen Cycloadditionen zu 4-Imino-azetidinonen-(2) (1-14) ein. Aliphatisch substituierte Carbodiimide sind reaktiver als aromatisch substituierte. Bei aliphatisch-aromatisch substituierten Carbodiimiden gelingt es daher, bevorzugt eine der beiden C=N-Doppelbindungen zur Reaktion zu bringen. Die Konstitutionen der 4-Iminoazetidinone-(2) ergeben sich aus IR- und NMR-Spektren in Verbindung mit chemischen Umwandlungen.
    Additional Material: 4 Tab.
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 75-77 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Higher Ring Systems with the Structural Characteristics of the Diamond-type Lattice, 1. Enamine Formation and Ring Fusion in the Case of Bicyclo[3,3,1]nonane-3,7-dioneBicyclo[3.3.1]nonane-3.7-dione can be condensed with pyrrolidine to form 1.3-dipyrrolidino-2-oxaadamantane. From this system the mono- and bis-pyrrolidinoenamine of bicyclo[3.3.1]-nonane-3.7-dione (3,5) can be obtained. The reaction of the bis-enamine 3 with ethyl bromomethylacrylate leads to the pentacycle 4.
    Notes: Bicyclo[3.3.1]nonandion-(3.7) (1) kann mit Pyrrolidin zum 1.3-Dipyrrolidino-2-oxa-adamantan (2) kondensiert werden. Aus diesem System sind das Mono- und Bis-pyrrolidin-Enamin des Bicyclo[3.3.1]nonandions-(3.7) (3.5) erhältlich. Über das Bis-Enamin 3 kann mit α-Brom-methyl-acrylsäure-äthylester der Pentacyclus 4 auf gebaut werden.
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 92-109 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Copper(I)-diazabutadiene Halides1,4-Diazabuta-1,3-dienes react with cuprous halides to form strongly coloured, monomeric 1:1 adducts 2-11, 16-20, 24, 25, containing copper with threefold coordination. This coordination number determines the spectroscopic behaviour. While diazabutadiene complexes of other metals in low oxidation states show a long-wavelength absorption with strong metal-to-ligand CT character, in the copper complexes 2-11, 16-20, 24, 25 the metal terms are about equally important in the ground and excited state without showing the typical solvatochromism and the extremely high intensity of the chromogenic transition.
    Notes: 1.4-Diaza-butadiene-(1.3) bilden mit Kupfer(I)-halogeniden stark farbige, monomere 1:1-Komplexe 2-11, 16-20, 24, 25 mit dreifach koordiniertem Kupfer. Diese Koordination bestimmt das elektronenspektroskopische Verhalten. Während in Diazabutadien-Komplexen anderer Metalle in niedrigen Oxydationsstufen die längstwellige Absorption sehr starken Metall-Ligand-charge-transfer-Charakter hat, fehlt hier bei etwa gleich starker Beteiligung von Metalltermen im Grundzustand und angeregten Zustand die typische Solvatochromie und die extrem hohe Intensität des farbgebenden Übergangs.
    Additional Material: 6 Ill.
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 145-149 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and N.M.R. Spectra of Trimethyl(allylidene)- and -(benzylidene)phosphoraneThe title compounds (1 and 2) have been prepared in a pure state for the first time. Their 1H n. m. r. spectra could be completely analysed and the data obtained are taken as evidence for a delocalisation of the ylidic carbanionic charge into the π-system.
    Notes: Trimethyl-allyliden- und -benzyliden-phosphoran (1 und 2) wurden erstmals rein dargestellt. Die 1H-NMR-Spektren ließen sich vollständig analysieren und im Sinne einer Delokalisierung der negativen Ladung in das π-System deuten.
    Additional Material: 1 Tab.
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  • 74
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaction of Organophosphorus CH-acidic Compounds with Schiff Bases in the Presence of Acid and Alkaline Catalysts, V. Reaction of Esters of Propylbenzylphosphinic Acid in the Presence of Sodium AmideThe reaction of esters 1 of propylbenzylphosphinic acid with Schiff bases 2 in the presence of sodium amide has been studied. In ether at -33° esters of (2-arylamino-1,2-diarylethyl)-propylphosphinic acids (3 and 4) are obtained in 20-81% yields. In ether at 10° and in liquid ammonia small amounts of trans-olefins (5) are formed along with the adducts 3 and 4 (the yields of which decrease). The reactivity of 1 is compared with that of the esters of benzyl-phosphonic acid, and the mechanism of the reaction of 1 with 2 is discussed.
    Notes: Bei der Umsetzung der Propyl-benzyl-phosphinsäureester 1 mit Schiffschen Basen 2 in Gegenwart von Natriumamid entstehen in Äther bei -33° Ester der [2-Arylamino-1.2-diaryläthyl]-propyl-phosphinsäuren (3 und 4) in 20-81 proz. Ausbeute. In Äther bei 10°, in geringem Umfang auch in flüssigem Ammoniak, bilden sich neben den verringert auftretenden Addukten 3 und 4 auch noch trans-Olefine (5). Die Reaktionsfähigkeit von 1 im Vergleich zu den Benzylphosphonsäureestern sowie der Mechanismus ihrer Umsetzung mit 2 werden diskutiert.
    Additional Material: 2 Tab.
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  • 75
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 220-227 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: cis- and trans-3.3′-Dimethoxy-5.5′-di-tert-butyldiphenoquinone-(4.4′)The two geometric isomers of 3.3′-dimethoxy-5.5′-di-tert-butyldiphenoquinone-(4.4′) (1) were isolated. The configurational assignment was made on the basis of n.m.r. spectra and the X-ray diffraction pattern from single crystals. The free enthalpy of activation for the cis/trans-isomerisation was determined. -p-Diphenoquinones with different substituents in both rings, which were needed as model compounds, could be prepared for the first time.
    Notes: Die beiden geometrischen Isomeren des 3.3′-Dimethoxy-5.5′-di-tert.-butyl-diphenochinons-(4.4′) (1) wurden isoliert. Die Konfigurationszuordnung gelang anhand der NMR-Spektren sowie von Einkristall-Röntgenaufnahmen. Die Freie Aktivierungsenthalpie der cis/trans-Isomerisierung wurde bestimmt. -p-Diphenochinone mit verschiedenen Substituenten in beiden Ringen, als Vergleichssubstanzen benötigt, konnten erstmals dargestellt werden.
    Additional Material: 2 Ill.
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  • 76
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 290-300 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reductive Rearrangements of the Retrobenzilic Acid Type Induced by Lewis Acids, VI. Crossing ExperimentsBy a series of crossing experiments the reductive retrobenzilic acid rearrangements of 5,5-diaryldithiohydantoins (1) and 4,4-diaryl-2-imidazoline-5-thiones (3), induced by aluminium chloride and yielding the corresponding 4,5-diaryl-4-imidazoline-2-thiones (2) and 4,5-diarylimidazoles (4), respectively, were shown to proceed intramolecularly.
    Notes: Durch eine Serie von Kreuzungsversuchen wird der intramolekulare Verlauf der durch Aluminiumchlorid ausgelösten reduktiven Retrobenzilsäure-Umlagerung von 5.5-Diaryl-dithiohydantoinen (1) und 4.4-Diaryl-Δ2-imidazolin-thionen-(5) (3) zu 4.5-Diaryl-Δ4-imidazolin-thionen-(2) (2) bzw. 4.5-Diaryl-imidazolen (4) erwiesen.
    Additional Material: 2 Tab.
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  • 77
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 348-349 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 78
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 353-359 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Are Absolute Asymmetric Photosyntheses Possible?The addition of carbenes, generated from diazoalkanes by circularly polarized light, to trimethylethylene (1) yielded optically inactive cyclopropanes. Attempts to obtain a chiral photochemical cyclodimerisation of cyclopent-1-en-3-one (4) or to reproduce two absolute asymmetric photosyntheses described earlier also failed. Thus such syntheses appear to be questionable.
    Notes: Mit zirkular polarisiertem Licht aus Diazoalkanen erzeugte Carbene lieferten bei der Reaktion mit Trimethyläthylen (1) optisch inaktive Cyclopropane. Ebenso negativ verliefen Versuche, eine chirale photochemische Cyclodimerisierung von Cyclopenten-(1)-on-(3) (4) zu erzielen oder zwei früher beschriebene absolute asymmetrische Photosynthesen zu reproduzieren. Die Möglichkeit derartiger Synthesen scheint damit in Frage gestellt.
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  • 79
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 360-364 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1:1-Complexes of Mercuric Halides with MethyldiphenylstibineThe complexes [HgX2·SbCH3(C6H5)2]2 mit X=Cl (5), Br (6), J (7) precipitated on combination of equimolar amounts of the components in methanol or acetone solution. Dimeric, halogen-bridged structures for these complexes have been derived from infrared spectra (300-33/cm). The ligand methyldiphenylstibine (4) has been obtained in 89% yield by reaction of dijodomethylstibine (3) with phenylmagnesium bromide.
    Notes: Die Komplexe [HgX2·SbCH3(C6H5)2]2 mit X=Cl (5), Br (6), J (7) fallen bei der Vereinigung äquimolarer Mengen der Komponenten in Methanol- oder Aceton-Lösung aus. Dimere, halogenverbrückte Strukturen dieser Komplexe werden aus Infrarotspektren (300-33/cm) abgeleitet. Der Ligand Methyldiphenylstibin (4) wird durch Reaktion von Dijodmethylstibin (3) mit Phenylmagnesiumbromid in 89 proz. Ausbeute erhalten.
    Additional Material: 2 Tab.
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  • 80
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 407-411 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of α-Halocarbonyl Compounds with the Guanidine System. II. Reaction of ω-Bromoacetophenone with Anilinoguanidineω-Bromoacetophenone reacts with anilinoguanidine to give 2-amino-1-anilino-4-phenylimidazole (1a). On treatment with boiling hydrochloric acid 1a undergoes benzidine-like rearrangement yielding 2-amino-4(5)-phenyl-5(4)-[p-aminophenyl]-imidazole (6).
    Notes: ω-Brom-acetophenon reagiert mit Anilino-guanidin zu 2-Amino-1-anilino-4-phenyl-imidazol (1a), das durch siedende Salzsäure benzidinartig in 2-Amino-4(5)-phenyl-5(4)-[p-amino-phenyl]-imidazol (6) umgelagert wird.
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  • 81
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 429-439 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A Stereoselective Synthesis of cis-3-Aryl-2-ethoxycarbonyl-5-pyrrolidonescis-3-Aryl-2-ethoxycarbonyl-5-pyrrolidones (6) are obtainable from 3-aryl-2,2-bis(ethoxy-carbonyl)-5-pyrrol idones(1) via their dicarboxy-derivatives (3) or their half-esters (5) by moderate stereoselective decarboxylation.
    Notes: Aus 3-Aryl-2.2-bis-äthoxycarbonyl-pyrrolidonen-(5) (1) lassen sich über die Dicarboxy-Verbindungen (3) oder über die Halbester (5) durch mäßig stereoselektive Decarboxylierung cis-3-Aryl-2-äthoxycarbonyl-pyrrolidone-(5) (6) gewinnen.
    Additional Material: 6 Tab.
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  • 82
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 456-460 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Chemical Synthesis of 2.4-Dithiopyrimidine Nucleoside-5′-mono- and -polyphosphatesThe synthesis of 2-thiothymidine-5′-phosphate (3), 2.4-dithiothymidine-5′-triphosphate (8c), 2.4-dithiouridine-5′-diphosphate (7a), 2.4-dithioribothymidine-5′-diphosphate (7b), and 2.4-dithiouridine-5′-triphosphate (8a) is reported. The behaviour in paper chromatography and paper electrophoresis as well as the phosphate content have been used as criteria of the purity.
    Notes: 2-Thio-thymidin-5′-phosphat (3), 2.4-Dithio-thymidin-5′-triphosphat (8c), 2.4-Dithio-uridin-5′-diphosphat (7a), 2.4-Dithio-ribothymidin-5′-diphosphat (7b) und 2.4-Dithio-uridin-5′-triphosphat (8a) wurden synthetisiert. Als Reinheitskriterien dienen das Verhalten in Papierchromatographie sowie Papierelektrophorese und der Phosphatgehalt.
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  • 83
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 519-523 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: E.S.R. Investigation of the Dinaphtho[2.3-c:2′.3′-h]phenothiazinyl Radical8H-Dinaphtho[2.3-c : 2′.3′-h]phenothiazine (1), obtained by reaction of di-2-anthrylamine with sulfur, yields the stable free radical 4 by dehydrogenation. For the solid state a free radical content of 85% has been determined by e. s. r. Solutions of 4 gave a complex e. s. r. spectrum which is discussed in connection with Hückel calculations.
    Notes: Das aus 2.2′-Dianthrylamin durch Umsetzung mit Schwefel zugängliche 8H-Dinaphtho-[2.3-c: 2′.3′-h]phenothiazin (1) liefert bei der Dehydrierung das stabile freie Radikal 4. Der Radikalgehalt beträgt im Kristall nach ESR-Messungen 85%. Lösungen von 4 liefern ein linienreiches ESR-Spektrum, das im Zusammenhang mit Hückel-Rechnungen diskutiert wird.
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  • 84
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 544-548 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: SO3-Insertion into Organopentacarbonylrhenium(I) CompoundsThe hitherto unknown sulfonato complexes CH3SO3ReI(CO)5 (4), C6H5SO3ReI(CO)5 (5), and p-CH3—C6H4SO3ReI (CO)5 (6) are obtained according to equation (1) by insertion of SO3 into the metal-carbon bond of CH3Re(CO)5 (1), C6H5Re(CO)5 (2), and p-CH3—C6H4Re(CO)5 (3). The composition and the structure of these compounds result from 1H n. m. r., mass, and i. r. spectroscopic investigations.
    Notes: Durch Einschiebung von SO3 in die Metall-Kohlenstoff-Bindung von CH3Re(CO)5 (1), C6H5Re(CO)5 (2) und p-CH3—C6H4Re(CO)5 (3) gelingt gemäß Gl. (1) die Darstellung der noch unbekannten Sulfonato-Komplexe CH3SO3ReI(CO)5 (4), C6H5SO3ReI(CO)5 (5) und p-CH3—C6H4SO3ReI(CO)5 (6). Die Zusammensetzung und Struktur dieser Verbindungen wurde mit Hilfe von 1H-NMR-, massen- und IR-spektroskopischen Untersuchungen ermittelt.
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  • 85
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 577-592 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Organic Peroxides, IX. Preparation and Thermolysis of tert-Butyl α-Aryloxy- and α-ArylthioperacetatesEleven tert-butyl α-aryloxyperacetates and four tert-butyl α-arylthioperacetates were prepared and characterized by spectra and analyses. The products and rates of their thermolyses are explained by a homolytic fragmentation mechanism. The rates are predominantly influenced by a polar effect. This is supported by the observation of Hammett relations in both series (σ = -1.1 and -1.3).
    Notes: 11 α-Aryloxy-peressigsäure-tert.-butylester und 4 α-Arylmercapto-peressigsäure-tert.-butylester wurden synthetisiert und durch Spektren und Elementaranalysen charakterisiert. Die Thermolyse dieser Peroxide erfolgt durch homolytische Fragmentierung. Ihre Geschwindigkeit gehorcht in beiden Reihen der Hammett-Beziehung mit σ = -1.1 bzw. -1.3 und unterliegt somit einem polaren Effekt.
    Additional Material: 9 Tab.
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  • 86
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 653-660 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Preparation of Fluorocyclotriphosphazenes with Phosphazene Side ChainsFluorocyclotriphosphazenes with phosphazene side chains were prolonged by the alternating reactions of hexamethyldisilazane and phosphorus pentachloride (1-8). The compounds formed contain up to six alternating (PN) bonds. Reactions of heptamethyldisilazane and methylamine give 9 and 10. Substitution reactions with the higher ring compounds yield 11-14. The properties of these substances are described and their structures could be likely prooved on the basis of 31P and 19F n. m. r. investigations. The compounds are further characterized by analysis and i. r. spectra.
    Notes: Fluorcyclotriphosphazene mit Phosphazenseitenkette werden durch alternierende Reaktionen mit Hexamethyldisilazan und Phosphorpentachlorid verlängert (1-8). Dabei entstehen Verbindungen, die bis zu sechs alternierende (PN)-Bindungen enthalten (7, 8). Umsetzungen mit Heptamethyldisilazan und Methylamin ergeben 9 und 10. Substitutionen an höheren Ringverbindungen führen zu 11-14. Die Eigenschaften dieser Substanzen werden beschrieben und ihre Struktur durch 31P- und 19F-NMR-Untersuchungen wahrscheinlich gemacht. Die Verbindungen werden weiterhin durch Analysen und IR-Spektren charakterisiert.
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  • 87
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 661-664 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 88
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 677-678 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 89
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 683-685 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 90
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 691-695 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Degradation Mechanism of Polyphosphoric Acid EstersPhenyl and methyl polyphosphates were reacted with small amounts of phenol, the course of the degradation reactions being followed by 31P n. m. r. spectroscopy of the obtained reaction mixtures. The analysis reveal general rules for the nucleophilic degradation of polyphosphate esters.
    Notes: Polyphosphorsäure-phenylester und -methylester wurden mit kleinen, Mengen Phenol umgesetzt und der Gang der Abbaureaktionen mit Hilfe der 31P-Kernresonanzspektren der entstandenen Reaktionsgemische untersucht. Die Analyse ergibt allgemeine Regeln für den nucleophilen Abbau von Polyphosphorsäureestern.
    Additional Material: 2 Ill.
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  • 91
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 705-716 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Course of the Pyridylation of Indoles and Pyrrolinones with Pyridine and BenzoylchlorideA mixture of pyridine and benzoyl chloride forms an SE reagent whose reaction with indoles and pyrrolin-2-ones is investigated. Indoles are converted to dihydropyridylindoles, e. g. 1, or to pyridylindoles, e. g. 3, whereas pyrrolinones undergo aromatization to pyrroles, e. g. 6, 7 or 10, with elimination of the amide oxygen. Reaction mechanisms are proposed and confirmed by the isolation of intermediates.
    Notes: Ein Gemisch von Benzoylchlorid und Pyridin stellt ein SE-Reagenz dar. dessen Reaktion an Indolen und Pyrrolinonen-(2) untersucht wird. Mit Indolen bilden sich Dihydropyridylindole (z. B. 1) bzw. Pyridylindole (z. B. 3), während Pyrrolinone unter Eliminierung des Amid-Sauerstoffs zu Pyrrolderivaten wie 6, 7 oder 10 aromatisiert werden. Reaktionsmechanismen werden vorgeschlagen und an Zwischenprodukten belegt.
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  • 92
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 717-721 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Organic Phosphorus Compounds, 68. Preparation and Properties of Tetrakis(diphenylphosphine)nickel(0)The title compound, 1, was prepared by reacting of diphenylphosphine with bis(π-allyl)nickel, tetrakis(triphenylphosphine)nickel(0) (2), nickel-powder, or nickel(II) bromide. The structure of 1 was elucidated by Zerewitinoff method, i. r. and n. m. r. spectra. The alkylation of metalated 1 was not successful.
    Notes: Die Titelsubstanz 1 wurde durch Einwirkung von Diphenylphosphin auf Bis-π-allyl-nickel, Tetrakis(triphenylphosphin)-nickel(0) (2), Nickelpulver oder Nickel(II)-bromid dargestellt. Ihre Struktur wurde durch Zerewitinoff-Bestimmung, IR- und NMR-Spektren abgesichert. Eine Alkylierung von metalliertem 1 gelang nicht.
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  • 93
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 734-738 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of 1-Oxo-1.3.6.7-tetrahydro-5H-furo[3.4-b]pyrans and -thiopyransVarious 2-methyl-3-ethoxycarbonyl-5.6-dihydro-4H-pyrans and -thiopyrans (1) react with bromine to form the corresponding 2-bromomethyl derivatives (2), which can be converted by heating to α.β-unsaturated γ-lactones (3) l. r. and n. m. r. spectra are reported and discussed.
    Notes: Die Bromierung verschiedener 2-Methyl-3-äthoxycarbonyl-5.6-dihydro-4H-pyrane und -thiopyrane (1) führt zu den entsprechenden 2-Brommethylverbindungen (2), die thermisch zu α.β-ungesättigten γ-Lactonen (3) cyclisiert werden können. Die Strukturen werden durch NMR- und IR-Spektren bewiesen.
    Additional Material: 1 Ill.
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  • 94
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 722-733 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contribution to the Chemistry of Boron, LVI. Derivatives of HydrazinodiphenylboraneHydrazinodiphenylboranes of the type XNH—NH—B(C6H5)2 are monomeric (1a). The acyl derivatives (1b—d) (X = C6H5CO, CH3CO, (C6H5)2P(O)) are all internally coordinated through BO-bonds. -N.N′-Bis(diphenylboryl)derivatives of hydrazines (2a—c) are obtained from (C6H5)2BN(C2H5)2 and N2H4, CH3NH—NH2, or CH3NH—NHCH3 but no N.N′-bis-(diphenylboryl)hydrazines can be prepared by this method. Compounds of the latter type (3) are accessible via N-lithiohydrazines. - The structures of the new compounds are discussed and some of their chemical properties reported.
    Notes: Hydrazino-diphenylborane des Typs XNH—NH—B(C6H5)2 sind monomer (1a); in den N-Acyl-N′-diphenylboryl-hydrazinen (1b—d) (X = C6H5CO, CH3CO, (C6H5)2P(O)) liegt vierbindiges Bor vor. - N.N′-Bis-diphenylborylierung an Hydrazinen gelingt durch Einwirkung von (C6H5)2BN(C2H5)2 auf Hydrazin, Methylhydrazin und N.N′-Dimethyl-hydrazin (Bildung von 2a—c). Diese Umaminierung kann zur Darstellung von N.N′-Bis(diphenylboryl)-hydrazinen nicht herangezogen werden; sie (3) sind jedoch über mit LiCH3 metallierte Hydrazinderivate zugängig. - Die Strukturen der neuen Verbindungen werden diskutiert und einige ihrer chemischen Eigenschaften beschrieben.
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 739-747 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Pteridines, XL. Synthesis of 3.N2.N2-TrimethylpterinsThe synthesis of 2-dimethylamino-3-methyl-4-oxo-3.4-dihydropteridines (18 and 19) is described. Comparisons of u. v. spectra reveal that the predominant tautomeric form of pterin (20) in solution possesses the 2-amino-4-oxo-3.4-dihydrostructure. Various alkylations of 4-aminopyrimidine derivatives are included in these investigations.
    Notes: Die Synthese von 2-Dimethylamino-4-oxo-3-methyl-3.4-dihydro-pteridinen (18 und 19) wird beschrieben. Durch UV-Spektrenvergleiche läßt sich zeigen, daß von den möglichen tautomeren Formen des Pterins (20) die 2-Amino-4-oxo-dihydro-Struktur in Lösung bevorzugt wird. Verschiedene Alkylierungen von 4-Amino-pyrimidin-Derivaten sind in die Untersuchungen mit einbezogen.
    Additional Material: 2 Ill.
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  • 96
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 787-791 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Investigation of Hydroacridines, VIII. Synthesis and Structure of 9-(4-Pyridyl)- and 9-(3-Pyridyl)-symm-octahydroacridineBy condensation of γ-and β-pyridinealdehyde with cyclohexanone, the tricyclic ketols 1 a and 1 b are obtained. Their oximes 2 give by thermal decomposition the corresponding 9-pyridyl-symm-octahydroacridines (3). The n. m. r. spectra are discussed.
    Notes: Durch Kondensation von γ-bzw, β-Pyridinaldehyd mit Cyclohexanon werden die tricyclischen Ketole 1 a und 1 b erhalten. Deren Oxime 2 ergeben durch thermische Zersetzung die entsprechenden 9-Pyridyl-symm-octahydroacridine (3). Die NMR-Spektren der dargestellten Verbindungen werden besprochen.
    Additional Material: 2 Tab.
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  • 97
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 770-779 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Pteridines, XLI. Synthesis of Pteridine-N-8-ribosides5-Nitro-4-(ribofuranosylamino) pyrimidines (1—4) are reduced to the corresponding 5-amino derivatives (5, 6) and these condensed with ethyl glyoxylate (7, 8). On subsequent ringclosure the pteridine-N-8-ribosides (9—12) are formed. U. v. and n.m.r. spectra are used for characterization.
    Notes: Zur Synthese der ersten Pteridin-N-8-riboside (9—12) werden 5-Nitro-4-ribofuranosylamino-pyrimidine (1—4) zunächst zu den 5-Aminoderivaten (5, 6) reduziert, diese dann mit Glyoxyl-säureester kondensiert (7, 8) und 7, 8 anschließend cyclisiert. Zur Charakterisierung der Produkte dienen UV- und NMR-Spektren.
    Additional Material: 2 Ill.
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  • 98
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 780-786 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Pteridines, XLII. A New Pteridine Synthesis from 4.5-Dihalouracils and EthylenediaminesA new approach for the synthesis of pteridine derivatives from 4.5-dihalouracils and ethylenediamines is described. pK values and u. v. absorption spectra of the synthesized products have been determined.
    Notes: Eine neue Synthesemöglichkeit für Pteridin-Derivate besteht in der Umsetzung von 4.5-Dihalogen-uracilen mit Äthylendiamin-Derivaten. pK-Werte und UV-Spektren der synthetisierten Verbindungen werden angegeben.
    Additional Material: 2 Ill.
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  • 99
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 792-801 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Orthoamides, XV. Formation of Ketene Aminals and Enediamines by Reaction of Bis(dimethylamino)-tert-butoxymethane with AzinesThe reaction of bis(dimethylamino)-tert-butoxymethane (2) with azines of aromatic aldehydes (4, 8) affords ketene aminals (5). Diazomethanes (9, 10) are formed as intermediates. Aryldiazomethanes react with 2 to give a mixture of ketene aminals (5), trans-enediamines (6), and cis-enediamines (7). The reaction of 2 with bis(2-pyridylmethylene)- (4n), with difurfurylidenehydrazine (4o) or with the azines 8, obtained by treatment of aromatic aldehydes with diphenylmethylenehydrazine, yields only ketene aminals (5). The reaction mechanism is discussed.
    Notes: Bei der Umsetzung von Bis-dimethylamino-tert.-butyloxy-methan (2) (Aminal-tert.-butyl-ester) mit Azinen aromatischer Aldehyde (4, 8) entstehen Ketenaminale (5) und als Zwischenprodukte Diazomethane (9, 10, ). Von diesen reagieren die Aryldiazomethane mit 2, zu Gemischen aus Ketenaminalen (5), trans- (6) und cis-Endiaminen (7). Bis-[Pyridyl-(2)-methylen]-(4n) und Difurfurylidenhydrazin (4o) sowie die aus aromatischen Aldehyden und Diphenyl-methylen-hydrazin dargestellten Azine 8 ergeben mit 2 ausschließlich Ketenaminale (5). Der Reaktionsablauf wird diskutiert.
    Additional Material: 4 Tab.
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  • 100
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 748-769 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies in the Pyrimidine Series, XXVI. A New Synthesis of 4-(Glycosylamino)-5-nitropyrimidinesFusion of some 4-amino-5-nitropyrimidines (1 4, 33, 36) with acylated D-ribose, D-glucose or acylated methylglycosides of D-ribofuranose, 2-deoxy-D-ribofuranose or L-arabinofuranose with an acidic catalyst produced the corresponding 5-nitro-4-(acylglycosylamino)pyrimidines (9-19 and others). In most cases both anomers were formed. which could be separated by preparative layer chromatography. The structure and configuration of the anomers were determined by u. v., n. m. r., and o. r. d. spectra. In the case of the ribofuranosides the thermodynamically more stable α-anomers were formed in larger amounts than the β-compounds. The influence of various catalysts and reaction conditions on the yield and the anomeric ratio was investigated.
    Notes: Die Schmelzkondensation verschiedener 5-Nitro-4-amino-pyrimidine (1—4, 33, 36) mit vollacylierter D-Ribose und D-Glucose sowie mit acylierten Methylglykosiden der D-Ribofuranose, 2-Desoxy-D-ribofuranose und L-Arabinofuranose zu den entsprechenden 5-Nitro-4-acylglykosylamino-pyrimidinen (9-19 und andere) wird beschrieben. Meist werden beide Anomere gebildet, die durch präparative Schichtchromatographie isoliert und mit Hilfe von UV-, NMR- und ORD-Spektren charakterisiert werden. Die Schmelzkondensation verläuft bei den angewandten Bedingungen unter thermodynamischer Steuerung. Im Falle der Ribofuranoside sind die α-Verbindungen stabiler als die β-Anomeren. Der Einfluß verschiedener Katalysatoren und Reaktionsbedingungen auf Ausbeute und Anomerenverhältnis wird untersucht.
    Additional Material: 4 Ill.
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