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On the Condensation Behaviour of Silanols. IV. Acid Catalyzed Condensation of Organodimethylsilanols in Dioxane/Water The condensation has been followed by GLC for silanols of the type XMe2SiOH in aqueous dioxane with HCl as catalyst. The obtained kinetic data and equilibrium constants are discussed with respect to the substituent dependence and the reaction mechanism.  相似文献   

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On the Condensation Behaviour of Silanoles. I. Condensation of Trimethylsilanol Using trimethylsilanol as model compound possibilities have been investigated to follow the silanol condensation by means of GLC, 1H-NMR, and IR. Kinetic data have been obtained for the acid and the base catalyzed condensation in aqueous dioxane and in toluene/water.  相似文献   

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On the Condensation Behaviour of Silanols. II. Acid Catalyzed Condensation of Dimethylsilanediol and Siloxanediols in Toluene/Water The acid catalyzed condensation of dimethylsilanediol and four methylsiloxanediols has been followed by GLC and IR, resp. The kinetic data are discussed with respect to the substituent dependence of the reaction rates, the reaction mechanism and the competition of silanol condensation and siloxane splitting.  相似文献   

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On the Condensation Behaviour of Silanoles. III. Base Catalyzed Condensation of Dimethylsilanediol and Siloxanediols in Toluene/Water The base catalyzed condensation of dimethylsilanediol and four methylsiloxanediols in toluene/water has been followed by GC and IR, resp. The kinetic data are discussed with respect to the substituent dependence of the reaction rates, the reaction mechanism, and the competition of silanol condensation and siloxane splitting.  相似文献   

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Zusammenfassung Die Umlagerung von N-Aryl-S,S-dimethylsulfimiden in Toluol/Triäthylamin liefert in hohen Ausbeuten o-Methylthiomethylaniline. In Alkohol verläuft die Umlagerung ohne Zusatz von Basen rascher, als Nebenreaktion läuft aber die Spaltung zu dem zugrunde liegenden aromatischen Amin ab. 2,6-Di-substituierte N-Arylsulfimide ergeben durch analoge Umlagerung Cyclohexadienimine. Die Umlagerung von N-Aryl-S,S-dialkylsulfimiden erfolgt langsamer als die der S-Methylderivate; sie führte in einem Fall in hohen Ausbeuten zu einem durch 1,2-Wanderung entstandenen N-Alkylthioalkylprodukt. Die Ergebnisse liefern Aufschlüsse über den Mechanismus von Methylthiomethylierungen von anilinen und Phenolen.
Methylthiomethylation of anilines and phenols, VII: Basecatalysed rearrangement of N-aryl-S.S-dialkyl sulfimides to o-methylthiomethyl anilines
Rearrangement of N-aryl-S.S-dimethyl sulfimides in toluene/triethyl amine yields high amounts of o-methylthiomethylated anilines. Rearrangement in ethanol without addition of base proceeds faster, but yields also the original aniline as by-product. 2.6-Di-substituted N-aryl sulfimides yielded on analogous rearrangement cyclohexadiene imines. The rearrangement of N-aryl-S.S-dialkyl sulfimides is slower than that of the S-methyl derivatives, and yielded in one case high amounts of N-alkylthioalkyl product formed via 1.2-migration. The results offer some informations on the mechanism of methylthiomethylations of anilines and phenols.


Herrn Prof. Dr.H. Nowotny gewidmet.

6. Mitt.:P. Claus, N. Vavra undP. Schilling, Mh. Chem.102, 1072 (1971).  相似文献   

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Analytical and Bioanalytical Chemistry -  相似文献   

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Zusammenfassung Die Kondensation von Rhodanin und seinen 3-Äthyl-, Allyl-, Carboxymethyl-und Phenylderivaten mit Indol-3-aldehyd und 5-Bromindol-3-aldehyd wurde in saurem Medium untersucht und die Reaktionsfähigkeit der einzelnen Aldehyde bei dieser Reaktion miteinander verglichen und diskutiert. Zehn in dieser Weise dargestellte Indolmethylenrhodanine sollen auf ihre fungiciden und antibakteriellen Eigenschaften geprüft werden.An den Zuschriften zu richten sind.  相似文献   

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On the Mechanism of the Photoreduction of Water with Ruthenium-trisbipyrazil as Sensitizer Oxidative and reductive primary steps can be differentiated in using Ru(bipy) and Ru(bipz), respectively, as sensitizers in a photochemically induced, Pt-catalyzed sacrificial water reduction. Experimental evidence for the reductive primary step and kinetic data are given for the electron transfer to methylviologen as relay compound.  相似文献   

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