Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 8 of 8 for “"Dioxanone"”.
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Asymmetrische Synthese von Sordidin, 7-epi-Sordidin und von Polyoeinheiten mit quartären Stereozentren
… banana plants has been achieved. Starting from dioxanone RAMP-hydrazone the desired C-7 epimers were prepared in 39% overall yield as a 1.5: 1 diastereomeric mixture over 14 steps. The epimers could be separated by preparative GC and thus, each of them could be obtained in high diastereomeric …
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Asymmetric synthesis of (+)-altholactone, a styryllactone from various goniothalamus species
… the well-established 1,3-diol building block, dioxanone (2,2-dimethyl-1,3-dioxan-5-one) 4, is described. This approach is based on establishment of the chiral centres by applying a RAMP-directed alkylation (ee > 98 %), an asymmetric aldol reaction (ee, de > 98 %) and a selective reduction (de > …
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Zur asymmetrischen Synthese von C-Azanucleosiden und 2-Amino-1,3-diolen
… was synthesized starting from the Dioxanone-RAMP-hydrazone in a seven-step procedure. The desired product was obtained in 47% overall yield, with excellent diastereo- and enatiomeric excess (de, ee>=96%).
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1,3-Aminoalkohole als Bausteine in der asymmetrischen Synthese von Azetidinen, Azetidincarbonsäuren und Piperidin-3-olen
… in a diastereoselective alkylation of the dioxanone SAMP-hydrazone. The obtained aminoketon was cyclised by reductive amination, yielding an acetal protected piperidin-3-ol. Different protecting group strategies were examined in order to increase the moderate yields and …
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Amorphe bioabbaubare Poly(esterurethan)netzwerksysteme mit Formgedächtniseigenschaften
… and diglycolide, E-caprolactone or p-dioxanone. Covalent networks are formed by polyaddition of precursors and a diisocyanate acting as coupling agent. The glass transition temperature Tg of the networks corresponds to the transition temperature Ttrans of the shape-memory effect. The …
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Novel sulfur containing electrophiles in asymmetric organocatalysis
… works well with acid-sensitive compounds such as dioxanone. We also evaluated the reactivity of various phenylthiomethyl amines towards protonation. We claim that aromatic are a stable class of compounds, which do not undergo acid-catalyzed cleavage of free amine to furnish a reactive carbocation. …
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Das Krankheitsbild und die Behandlungsalternativen der Unterlidretraktion bei Patienten mit Morbus Basedow nach transpalpebraler Orbitadekompression : Gegenüberstellung der Ergebnisse nach Konchaknorpel- und PDS-Folienimplantation in Hinsicht auf Funktionalität und Ästhetik
… results in 38 patients treated with thin Poly-p-dioxanone foil (PDS-foil) to those in 39 patients treated with auricular cartilage, between 1999 and 2005 at the Department of Plastic Surgery of Dreifaltigkeits-Hospital, Wesseling/Koeln. The records of 77 patients who underwent auricular cartilage …
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Asymmetrische Synthese von 2-Methyl-substituierten 1,3-Diolen
Nature employs dihydroxyacetonephosphate (DHAP) as a C3-building block for carbohydrate synthesis via enzyme catalyzed aldol reactions. Accordingly many groups focussed on broadening the scope of that enzyme catalyzed reaction. On the other hand a chiral, synthetic DHAP equivalent would not only be …