- A simple and efficient room temperature silylation of diverse functional groups with hexamethyldisilazane using CeO2 nanoparticles as solid catalysts
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In this study, a mild and efficient method is developed for the silylation of diverse functional groups using CeO2 nanoparticles (n-CeO2) as solid catalysts with hexamethyldisilazane (HMDS) as silylating agent at room temperature. Alcohols, phenols and acids are silylated to their respective silyl derivatives with faster reaction rate while amines and thiols required relatively longer reaction time. Moreover, the solid catalyst is easily be separated from the reaction mixture and recycled more than five times without any obvious decay in its activity. Powder X-ray diffraction (XRD), transmission electron microscope (TEM), UV–vis diffuse reflectance spectra (UV-DRS) and Raman analyses revealed identical structural integrity, particle size, absorption edge and valence state for the reused solid compared to the fresh solid catalyst.
- Anbu, Nagaraj,Vijayan, Chellappa,Dhakshinamoorthy, Amarajothi
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- Highly atom economical uncatalysed and I2-catalysed silylation of phenols, alcohols and carbohydrates, using HMDS under solvent-free reaction conditions (SFRC)
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An uncatalysed silylation of phenols, regardless on the aggregate state and nature of the substituents with 0.55 equiv of HMDS under solvent-free reaction conditions (SFRC) at room temperature is reported. Sterically hindered phenols, carbohydrates and most of the alcohols additionally required a catalytic amount (up to 2 mol %) of iodine. The reaction protocol is very simple; obtaining a pure product, particularly of uncatalysed reactions, was frequently a completely solvent-free process.
- Jereb, Marjan
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experimental part
p. 3861 - 3867
(2012/06/30)
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- PROCESS FOR THE PREPARATION OF 2 -HYDROXY- 4 -PHENYL -3, 4 -DIHYDRO-2H-CHROMEN- 6 -YL -METHANOL AND (R) - FESO - DEACYL
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The present invention regards an improved and industrially advantageous process for the preparation of the 2-hyaroxy-4-phenyl-3,4-dihydro-2H-chromen-6-yl-methanol intermediates, also called "feso chromenyl" and (R)-2-[3-(diisopropylamino)-l- phenylpropyl]-4-(hydroxymethyl)phenol, also called "(R)-feso deacyl", which are in turn used in the synthesis of fesoterodine and in particular of fesoterodine furnarate. This process utilises reagents which are non-toxic and manageable at industrial level and enables obtaining a new stable and non-hygroscopic crystalline form of the key intermediate "(R)-feso deacyl", called form B.
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Page/Page column 16-17
(2012/01/05)
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- Rapid and efficient trimethylsilyl protection of hydroxyl groups catalyzed by niobium(V) chloride
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An efficient and convenient procedure for the trimethylsilylation of a wide variety of alcohols, including primary, benzylic, secondary, and phenols with hexamethyldisilazane, has been developed. The reactions were carried out at room temperature in the presence of a catalytic amount of niobium(V) chloride and afforded the corresponding trimethylsilyl ethers in high to excellent yields in short time. Copyright Taylor & Francis Group, LLC.
- Hou, Jun-Tao,Chen, Hong-Li,Zhang, Zhan-Hui
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experimental part
p. 88 - 93
(2011/04/22)
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- Heterogeneous catalysis in trimethylsilylation of alcohols and phenols by zirconium sulfophenyl phosphonate
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Layered zirconium sulfophenyl phosphonate was found to be an efficient heterogeneous catalyst for the trimethylsilylation of alcohols and phenols.
- Curini, Massimo,Epifano, Francesco,Marcotullio, Maria Carla,Rosati, Ornelio,Costantino, Umberto
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p. 541 - 546
(2007/10/03)
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- PHENOLIC COMPOUNDS FROM ROOTS OF URTICA DIOICA
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Root extracts from Urtica dioica were separated into several classes of compounds by extraction with organic solvents at different pH values.The phenolic fraction was analysed by GC-MS after trimethylsilylation.This procedure allowed the identification of 18 phenolic compounds as well as the detection of eight lignans.The occurrence of some of these substances in this plant was previously unknown.
- Kraus, Rupert,Spiteller, Gerhard
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p. 1653 - 1659
(2007/10/02)
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- PREPARATION AND MASS SPECTROMETRIC CHARACTERIZATION OF DEUTERIUM-LABELLED PHENOL-FORMALDEHYDE RESINS
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Resol-type prepolymers were prepared by the condensation of phenol and formaldehyde as well as their deuterated analogues under base-catalysed conditions.Mass spectra of the individual compounds recorded following trimethylsilylation and gas chromatographic separation revealed the retention of labels at their original positions.Crosslinking by heat resulted in the formation of high-molecular-weight resins containing methylene and dimethylene ether type bridges (or their deuterated analogues) across the phenolic units.Loss of formaldehyde from methylene ether bridges upon heating without any scrambling of isotopes was ascertained by direct pyrolysis mass spectrometry.
- Prokai, Laszlo
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p. 901 - 906
(2007/10/02)
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