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Ficaria calthifolia (diploide Form, Typ1) wurde kürzlich nord-westlich des geschlossenen südosteuropäischen Verbreitungsgebiet auch in Deutschland gefunden, nämlich in Würzburg (2006) und an Elbedeichen in Brandenburg (2014) und Sachsen (2015). Ficaria calthifolia ist durch das Fehlen von verlängerten mehrgliedrigen Stängeln und die Abwesenheit von Brutknollen in den Blattachseln gekennzeichnet. Die 1–2 (3) Stängel von Ficaria calthifolia verbleiben überwiegend im Boden (hypogäisch), können aber im Laufe der Anthese aus dem Boden hervorwachsen. Die gestielten Laubblätter setzen sich aus Grundblättern und einer Rosette von bis zu 8 Stängelblättern pro Stängel zusammen. Letztere entspringen aus dem terminalen Stängelknoten (Stängelblatt-rosette). In Würzburg kommen zwei Populationen von Ficaria calthifolia vor, diploide Typ1-Pflanzen und triploide Typ2-Pflanzen. Letztere sind robuster, besitzen größere Blüten (bis 4 cm) und entwickeln nur vereinzelte reife Nüsschen. Pflanzen mit höherem Ploidiegrad (wahrscheinlich pentaploid, Typ3) wurden auch gefunden. Etwa 60% der 3 bis 8 Blütenstiele von Typ1-Pflanzen besitzt kein Stängelblatt, der Rest einen Knoten mit 1 bis 2 (3) Hochblättern. Die Zahl der Kronblätter beträgt 8 (vereinzelt 9), die durchschnittliche Zahl reifer, eiförmiger Nüsschen pro Fruchtstand beträgt 7 (Würzburg) / 14 (Elbe) (maximal 26). Aus vom Rhizom abgebrochenen und im Mai gepflanzten Speicherknollen keimten im Spätherbst desselben Jahrs neue Pflanzen. Der Jahreszyklus des Wurzelsystems wird beschrieben. Durch spontane Ablösungen einzelner Speicherknollen findet eine vegetative Vermehrung statt. Neben Nüsschen wären abgebrochene Speicherknollen für die Fernansiedlung der Sippe an Elbe (u.a. Verschleppung durch Hochwasser) und Main (Verschleppung durch Schiffe und andere Vektoren) ausreichend.
No abstract available.
The 2,2,5,5-tetraorganyl-1,4-dioxa-2,5-disilacyclohexanes 2a-2c were prepared by condensation of the corresponding (hydroxymethyl)diorganylsilanes 1 a-1 c. The constitution of the heterocycles was confirmed by elemental analyses, cryoscopic measurements, mass spectrometry, and NMR-spectroscopic \((^1H, ^{13}C)\) investigations. The molecular structure of 2 b was determined by X-ray diffraction analysis.
In the course of systematic investigations on sila-substituted parasympatholytics the diphenyl(2-aminoethoxymethyl)silanols 3b and 4b (and its carbon analogue 4a) were synthesized and characterized by their physical and chemical properties. In the solid state 4a and 4b form strong O-H---N hydrogen bonds, which are intramolecular (4a) and intermolecular (4b), respectively. 4a and 4b were found to be weak antimuscarinic agents (4b >4a) and strong papaverine-like spasmolytics (4a ≈4b).
The potentially curare-like silicon compounds 8a- 8f were synthesized and investigated with respect to their structure-activity relationships. The conformations of the compounds in the solid state and in solution were studied by X-ray diffraction analysis (8a- 8e) and IR NMR spectroscopy (8a- 8f), respectively. The muscle relaxing properties of 8a- 8f were investigated on the mouse. The observed structure-activity relationships are not in accordance with the classical "14 Å model" for neuromuscular blocking agents.
Sila-difenidol (6b), a sila-analogue of the drug difenidol (6a), was synthesized according to Scheme 1. 6b and its new precursors 3 and 5 were characterized by their physical and chemical properties, and their structures confirmed by elementary analyses, 1H NMR and mass spectroscopy. 6 b crystallizes orthorhombic \(P2_12_12_1\) with a = 11.523(1), b = 14.366(4), c = 11.450(1) Å, Z = 4, \(D_{ber} = 1.14 gcm^{-3}\). The structure was refined to R = 0.050 for 1897 reflexions. A strong nearly linear intramolecular O-H···N hydrogen bond of 2.685 Å is observed. The anticholinergic, histaminolytic and musculotropic spasmolytic activities of 6 a and 6 b are reported.
In the course of systematic studies on sila-substituted drugs the nifedipine-like 1.4-dihydropyridine derivatives 4a, 4b and 4c were prepared and investigated with respect to sila-substitution effects. By X-ray diffraction analyses 4a, 4b and 4c were found to be isostructural. The C/Si-analogues exhibit similar spasmolytic activities (in vitro, guinea pig ileum), comparable with that of nifedipine. However, the compounds differ substantially in their in vivo activity, as measured by the antihypertensive effect on the renal-hypertensive rat. The experimental results are discussed with respect to the carbon/silicon exchange.
The trimethylsilylalkyl acetoacetates 1 b and 2 b as well as their carba analogues 1 a and 2 a have been reduced microbiologically by Kloeckera corticis (ATCC 20109), leading to the corresponding ( + )-3(S)-hydroxybutanoates 3b, 4b, 3a, and 4a. The enantiomeric purity was found to be 80% (3a, 3b, 4b) and 65% (4a), respectively. The reduction of lb and 2b is - to our knowledge - the first example for a controlled microbiological transformation of organosilicon substrates.
The synthesis and the thermal behaviour of the (methylphenylsilyl)methyl carbonates \(CH_3(C_6H_5)Si(H)CH_2OC(O)X (6: X = OCH_3; 7: X = Cl; 8: X = N(CH_3)_2)\) is described. 8 rearranges in toluene solution at 100 °C quantitatively to give the carbam oyloxysilane \(C_6H_5(CH_3)_2SiOC(O)N(CH_3)_2\) (11), whereas neat 6 and 7 at 135 °C undergo quantitative formation of \(C_6H_5(CH_3)_2SiOCH_3\) (12) and \(C_6H_5(CH_3)_2SiCl\) (13), respectively. The formation of 12 and 13 is explained by a rearrangement reaction (by analogy to the rearrangement of 8), follow ed by a decarboxylation. The thermally induced transformations 6 →12, 7 →13, and 8 →11 were found to be first-order reactions with half-lifes of ~2.6 h (135 °C, neat), ~4.5 h (135 °C, neat), and ~3.7 h (100 °C, in toluene), respectively.
Organosilicon compounds 8, 9 and 10 with potential curare-like action and their precursors 0, 6 and 7 were synthesized for the first time. 0-10 were characterized by their physical and chemical properties, and their structures were confirmed by analyses, IH NMR and mass spectroscopy (only for 0-7). The pharmacological and toxicological data of 8, 9 and 10 are reported.