Fakultät für Chemie und Pharmazie - Digitale Hochschulschriften der LMU - Teil 04/06 Archiv

The synthesis and properties of explosive urea and triazine derivatives is investigated on behalf of the explosive parameters and the full characterization of the molecules. (Chapter I-III) The class of oxadiazole derivatives is enhanced from the known explosive 1,2,5 oxadiazole (furazane) derivatives to the 1,2,4 oxadiazole derivatives. This molecule class is thoroughly investigated by all terms of chemical and explosive material matter and especially the 1,2,4-oxadiazol-5-one derivatives are compared to the corresponding tetrazole derivatives which were by far the most investigated molecule moiety of Prof. Dr. T.M. Klapoetke et al. for more than the last ten years. The 1,2,4 oxadiazol-5-one derivatives do only value as comparable model molecule to the tetrazole but were found to be good explosives themselves. So the triaminoguanidinium 1,2,4-oxadiazol-5-onate is suitable as low temperature propellant, the potassium and cesium 1,2,4-oxadiazol-5-onate are found to be good additions for NIR-flares and last but not least the best performing molecule was found to be the 3,5-diamino-1,2,4-oxadiazolium 5-aminotetrazolate, which combines the stability of the oxadiazole moiety with the very exothermic properties of a tetrazole in its best way. (Chapter IV-V) The 3-amino-1,2,4(4H)-oxadiazol-5-one is investigated thoroughly and detected to be a chemically and thermodynamically more stable system which can be functionalized according to methods known prior in the working group. The 3-dinitromethyl-1,2,4(4H)-oxadiazol-5-one is found a promising explosive class which can be combined as anion with a wide range of cations to tailor the stability and performance. The overall conclusion is that the 1,2,4-oxadiazole are chemical suitable as well as secondary explosives, propellants and pyrotechnics.

DYNAMIC TRANSCRIPTOME ANALYSIS MEASURES RATES OF MRNA SYNTHESIS AND DECAY IN YEAST To obtain rates of mRNA synthesis and decay in yeast, we established dynamic transcriptome analysis (DTA). DTA combines non-perturbing metabolic RNA labeling with dynamic kinetic modeling. DTA reveals that most mRNA synthesis rates are around several transcripts per cell and cell cycle, and most mRNA half-lives range around a median of 11 min. DTA can monitor the cellular response to osmotic stress with higher sensitivity and temporal resolution than standard transcriptomics. In contrast to monotonically increasing total mRNA levels, DTA reveals three phases of the stress response. During the initial shock phase, mRNA synthesis and decay rates decrease globally, resulting in mRNA storage. During the subsequent induction phase, both rates increase for a subset of genes, resulting in production and rapid removal of stress-responsive mRNAs. During the recovery phase, decay rates are largely restored, whereas synthesis rates remain altered, apparently enabling growth at high salt concentration. Stress-induced changes in mRNA synthesis rates are predicted from gene occupancy with RNA polymerase II. Thus, DTA realistically monitors the dynamics in mRNA metabolism that underlie gene regulatory systems.