Thesis (Doctoral)--Freie Universität Berlin, 1982.

Würzburg, University, Diss., 2009. / Erscheinungsjahr an der Haupttitelstelle: 2008.

Thesis (Ph. D.)--Grossherzoglich Hessischen Ludwigs-Universität zu Giessen, 1901. / Cover title. Includes bibliographical references.

<p>The goals for the project “Synthesis and Functionaliszation of 3-Nitropyridines” were first to further optimize the procedures for nitration of 3-nitropyridines, and then investigate some aspects of the mechanism. Further was the reactivity of 3- nitropyridines investigated, especially the reactivity toward nitrogen nucleophiles.</p><p>Pyridines can be nitrated by reacting the pyridine with dinitrogen pentoxide in an organic solvent and then pour the slurry formed into an aqueous solution of sodium bisulfite. After some hours of stirring, the 3-nitropyridine can be isolated.</p><p>After investigation of the effect of changes in sodium bisulfite concentration, reaction medium and temperature a modified procedure for the nitration was developed. In this procedure the pyridine compound was reacted with dinitrogen pentoxide in dichloromethane or nitro methane and the resulting slurry poured into a solution of bisulfite dissolved in methanol/water (3:1). After some hours of stirring at room temperature the 3-nitropyridine was isolated.</p><p>The mechanism of the nitration of pyridines with dinitrogen pentoxide was studied, and is shown in the next scheme. The author studied the migration of the nitro group from the nitrogen to the -carbon. It has been by others shown that pyridine and dinitrogen pentoxide forms N-nitro pyridinium nitrate. Which is attacked by the bisulfite nucleophile in either 2- or 4- position to give N-nitro-2- dihydropyridine-2-sulfonate and N-nitro-1,4-dihydropyridine-4-sulfonate. The nitro group in N-nitro-2-dihydropyridine-2-sulfonate migrates to the -carbon, to give via addition of one more bisulfite ion a tetrahydro intermediate. From this the 3-nitropyridine is formed by loss of two bisulfite ions. The mechanism for the nitro group migration was previously not known. The results presented in this thesis together with previous results conclude with that the migration takes place as a [1,5] sigmatropic shift.</p>

The goals for the project “Synthesis and Functionaliszation of 3-Nitropyridines” were first to further optimize the procedures for nitration of 3-nitropyridines, and then investigate some aspects of the mechanism. Further was the reactivity of 3- nitropyridines investigated, especially the reactivity toward nitrogen nucleophiles. Pyridines can be nitrated by reacting the pyridine with dinitrogen pentoxide in an organic solvent and then pour the slurry formed into an aqueous solution of sodium bisulfite. After some hours of stirring, the 3-nitropyridine can be isolated. After investigation of the effect of changes in sodium bisulfite concentration, reaction medium and temperature a modified procedure for the nitration was developed. In this procedure the pyridine compound was reacted with dinitrogen pentoxide in dichloromethane or nitro methane and the resulting slurry poured into a solution of bisulfite dissolved in methanol/water (3:1). After some hours of stirring at room temperature the 3-nitropyridine was isolated. The mechanism of the nitration of pyridines with dinitrogen pentoxide was studied, and is shown in the next scheme. The author studied the migration of the nitro group from the nitrogen to the -carbon. It has been by others shown that pyridine and dinitrogen pentoxide forms N-nitro pyridinium nitrate. Which is attacked by the bisulfite nucleophile in either 2- or 4- position to give N-nitro-2- dihydropyridine-2-sulfonate and N-nitro-1,4-dihydropyridine-4-sulfonate. The nitro group in N-nitro-2-dihydropyridine-2-sulfonate migrates to the -carbon, to give via addition of one more bisulfite ion a tetrahydro intermediate. From this the 3-nitropyridine is formed by loss of two bisulfite ions. The mechanism for the nitro group migration was previously not known. The results presented in this thesis together with previous results conclude with that the migration takes place as a [1,5] sigmatropic shift.

Techn. Hochsch., Diss., 2000--Aachen.

Mit der präparativen Synthese der Tetraorganozinn(IV)-verbindung 4-[2-(Triphenylstannyl)ethylpyridin, Ph3Sn-(CH2)2-4Py, ausgehend von der Lewis-Säure Triphenylzinnchlorid, Ph3SnCl, konnte eine Blockade der reaktiven Lewis-Säure in Form des Zinnatoms dargestellt werden, in dem vier organische Liganden das zentrale Zinnatom einerseits topologisch und andererseits durch die weitreichende Stabilität von Zinn-Kohlenstoff-Bindungen abschirmen. Die Funktionalität konnte dadurch auf das funktionelle Stickstoffatom mit seiner Lewis-Base-Funktion, was neben der strukturellen Charakterisierung von 4-[2-(Triphenylstannyl)ethylpyridin durch eine Vielzahl an weiteren Verbindungen gezeigt werden konnte, verschoben werden. Synthesemöglichkeiten zu Komplexen von 4-[2-(Triphenylstannyl)ethylpyridin mit Übergangsmetalldichloriden, Triorganozinnhalogeniden und Diorganozinndihalogeniden konnten ebenso wie Salzbildungen zu 4-[2-(Triphenylstannyl)ethylpyridinium-halogeniden gezeigt werden. Verschiedentliche Umsetzungen konnten die Neigung der Bildung von Kokristallisaten zusammen mit protonierten Formen von 4-[2-(Triphenylstannyl)ethylpyridin und weiteren Stoffklassen zeigen. Durch Umsatz mit meta-Chlorperbenzoesäure wurde das Oxidationsprodukt 4-[2-(Triphenylstannyl)ethylpyridin-N-oxid dargestellt. Die Reaktivierung der eigentlichen Lewis-Säure-Funktion des Zinnatoms wurde über Synthesen mit Halogenwasserstoffsäuren im Verhältnis über 1 : 2 realisiert. Die Arbeit thematisert neben den Studien zur Synthese und chemischen Funktionalität ausführlich relevante Strukturaspekte der über Röntendiffraktometrie gewonnenen Strukturparameter der dargestellten Verbindungen.

This work deals with the structural analysis of layered zirconium sulfophenylphosphonates and their intercalates with the use of the classical molecular simulation methods. The inner composition of both fully and partially sulfonated layers was determined in agreement with available experimental data, especially chemical analysis, thermogravimetric measurements and X-ray diffraction. The calculations revealed the positions of the water molecules in the planes of sulfo groups which strongly affect the resultant diffraction pattern. Within the zirconium sulfophenylphosphonate layered structure, the arrangements of intercalated species based on optically active dipyridylamine molecules and cations of sodium, copper and iron were solved with the respect to the agreement with experimental results and values of potential energy. In case of the dipyridylamine molecules and its derivatives, the resultant disordered partially row arrangements of the organic molecules in the interlayer were showed to influence the dipole moment of the intercalate. From this point of view, nitro-derivative has been picked out as the most suitable for potential applications. Regarding the intercalated cations, sodium cations take up the space of water molecules next to the sulfo groups while copper and iron cations are distributed in a...

The reaction of the lithium tris(2-pyridyl)stannate [LiSn(2-py6OtBu)3] (py6OtBu = C5H3N-6-OtBu),1, with the element(II) amides E{N(SiMe3)2}2 (E = Sn, Pb) afforded complexes [LiE{Sn(2 py6OtBu)3}3] for E = Sn (2) and E = Pb (3), which reveal three Sn–E bonds each. Compounds 2 and 3 have been characterized by solution NMR spectroscopy and X-ray crystallographic studies. Large 1J(119Sn–119/117Sn) as well as 1J(207Pb–119/117Sn) coupling constants confirm their structural integrity in solution. However, contrary to 2, complex 3 slowly disintegrates in solution to give elemental lead and the hexaheteroarylditin [Sn(2-py6OtBu)3]2 (4).

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