Strukturvergleich bei 9,10-Dihydro-9,10-anthrylen-Verbindungen des Magnesiums und des Alkylaluminiums / Comparison between the Structures of 9,10-Dihydro-9,10-anthrylene Compounds of Magnesium and Alkylaluminium

1985 ◽  
Vol 40 (11) ◽  
pp. 1504-1510 ◽  
Author(s):  
Herbert Lehmkuhl ◽  
Abdul Shakoor ◽  
Klaus Mehler ◽  
Carl Krüger ◽  
Yi-Hung Tsay
Keyword(s):  
Ring Size ◽  
Coordination Geometry ◽  
Chemical Behaviour ◽  
Trimethylsilyl Derivatives ◽  
Derivatives Of

In magnesium as well as in aluminium derivatives of anthracene (1−4, 8) and its trimethylsilyl derivatives (5, 6 and 11), the metals occupy the axial positions at C9 and CIO, to form five-, seven- or ten-membered metallacycles, respectively, in 1−3, 5, 6 and 11. It appears that the metalla-ring size, and thus the coordination geometry of the bridging metal is of influence upon the chemical behaviour.

ChemInform Abstract: TRIMETHYLSILYL DERIVATIVES OF TITANIUM

1978 ◽  
Vol 9 (19) ◽  
Author(s):  
G. A. RAZUVAEV ◽  
V. N. LATYAEVA ◽  
L. I. VYSHINSKAYA ◽  
A. V. MALYSHEVA ◽  
G. A. VASI'EVA
Keyword(s):  
Trimethylsilyl Derivatives ◽  
Derivatives Of

scholarly journals The Fluoride Anion-Catalyzed Sulfurization of Thioketones with Elemental Sulfur Leading to Sulfur-Rich Heterocycles: First Sulfurization of Thiochalcones

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 822
Author(s):  
Grzegorz Mlostoń ◽  
Jakub Wręczycki ◽  
Katarzyna Urbaniak ◽  
Dariusz M. Bieliński ◽  
Heinz Heimgartner
Keyword(s):  
Elemental Sulfur ◽  
Fluoride Anion ◽  
Ring Size ◽  
Mild Conditions ◽  
Tetrabutylammonium Fluoride ◽  
Cesium Fluoride ◽  
Secondary Reactions ◽  
Derivatives Of

Fluoride anion was demonstrated as a superior activator of elemental sulfur (S8) to perform sulfurization of thioketones leading to diverse sulfur-rich heterocycles. Due to solubility problems, reactions must be carried out either in THF using tetrabutylammonium fluoride (TBAF) or in DMF using cesium fluoride (CsF), respectively. The reactive sulfurizing reagents are in situ generated, nucleophilic fluoropolysulfide anions FS(8−x)−, which react with the C=S bond according to the carbophilic addition mode. Dithiiranes formed thereby, existing in an equilibrium with the ring-opened form (diradicals/zwitterions) are key-intermediates, which undergo either a step-wise dimerization to afford 1,2,4,5-tetrathianes or an intramolecular insertion, leading in the case of thioxo derivatives of 2,2,4,4-tetramethylcyclobutane-1,3-dione to ring enlarged products. In reactions catalyzed by TBAF, water bounded to fluoride anion via H-bridges and forming thereby its stable hydrates is involved in secondary reactions leading, e.g., in the case of 2,2,4,4-tetramethyl-3-thioxocyclobutanone to the formation of some unexpected products such as the ring enlarged dithiolactone and ring-opened dithiocarboxylate. In contrast to thioketones, the fluoride anion catalyzed sulfurization of their α,β-unsaturated analogues, i.e., thiochalcones is slow and inefficient. However, an alternative protocol with triphenylphosphine (PPh3) applied as a catalyst, offers an attractive approach to the synthesis of 3H-1,2-dithioles via 1,5-dipolar electrocyclization of the in situ-generated α,β-unsaturated thiocabonyl S-sulfides. All reactions occur under mild conditions and can be considered as attractive methods for the preparation of sulfur rich heterocycles with diverse ring-size.

ChemInform Abstract: N-Trimethylsilyl Derivatives of Thiolactams in N-Amido- and N- Sulfonamidoalkylation.

ChemInform ◽  
2010 ◽  
Vol 25 (43) ◽  
pp. no-no
Author(s):  
V. N. SERGEEV ◽  
S. A. ARTAMKIN ◽  
YU. I. BAUKOV
Keyword(s):  
Trimethylsilyl Derivatives ◽  
Derivatives Of

scholarly journals Gas-Chromatographic Determination of the Trimethylsilyl Derivatives of Polyhydric Alcohol Humectants in Tobacco and in Tobacco Smoke

1971 ◽  
Vol 6 (2) ◽  
Author(s):  
N. Carugno ◽  
S. Rossi ◽  
G. Lionetti
Keyword(s):  
Gas Chromatography ◽  
Mass Spectra ◽  
Triethylene Glycol ◽  
Chromatographic Determination ◽  
Flame Ionization ◽  
Trimethylsilyl Derivatives ◽  
Gas Chromatographic Method ◽  
Derivatives Of ◽  
Quantitative Procedure

AbstractA qualitative and quantitative procedure has been developed for the determination of humectants in manufactured tobacco by gas-chromatographic method with a flame ionization detector. It consists of extraction with methanol, concentration of the extract and treatment with Tri-Sil reagents. The operating gas-chromatographic conditions are set forth. Samples of tobacco containing glycerine, propylene glycol, diethylene glycol, triethylene glycol, 1-3 butylene glycol and sorbitol have been analysed with recoveries, for the first five ones, in the range of 95-104 %. In order to verify that each chromatographic peak corresponded to the relative glycol, with no interference by other silylated compounds, the mass spectra were obtained through the combination of gas-chromatography with mass spectrometry. The results achieved confirm, as far as tobacco is concerned, that the procedure is accurate and precise. The same method for the determination of humectants was extended to cigarette smoke. Even though this involves morecomplicated problems, as compared to tobacco, because of the presence of silylated compounds, it was found that, for certain glycols, the gas-chromatography of the trimethyl derivatives can be also used as a method of analysis. The mass spectra of some polyhydric alcohols are shown

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