624286-50-6Relevant articles and documents
Nanoporous Na+-montmorillonite perchloric acid as an efficient and recyclable catalyst for the chemoselective protection of hydroxyl groups
Mashhadinezhad, Maryam,Shirini, Farhad,Mamaghani, Manouchehr
, p. 2099 - 2107 (2019/01/03)
Nanoporous Na+-montmorillonite perchloric acid as a novel heterogeneous reusable solid acid catalyst was easily prepared by treatment of Na+-montmorillonite as a cheap and commercially available support with perchloric acid. The catalyst was characterized using a variety of techniques including X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), energy dispersive X-ray spectroscopy (EDX), pH analysis and determination of the Hammett acidity function. The prepared reagent showed excellent catalytic activity for the chemoselective conversion of alcohols and phenols to their corresponding trimethylsilyl ethers with 1,1,1,3,3,3-hexamethyldisilazane (HMDS) at room temperature. Deprotection of the resulting trimethylsilyl ethers can also be carried out using the same catalyst in ethanol. All reactions were performed under mild and completely heterogeneous reaction conditions in good to excellent yields. The notable advantages of this protocol are: short reaction times, high yields, availability and low cost of the reagent, easy work-up procedure and the reusability of the catalyst during a simple filtration.
Chlorozincate(II) acidic ionic liquid: Efficient and biodegradable silylation catalyst
Abbasi, Faezeh,Azizi, Najmedin,Abdoli-Senejani, Masumeh
, (2017/09/30)
A practical and highly efficient silylation of alcohol and phenol derivatives with hexamethyldisilazane (HMDS) using acidic ionic liquids under mild reaction conditions is described. A series of Br?nsted as well as Br?nsted–Lewis acidic ionic liquids were prepared and their performance investigated for the silylation of a wide variety of alcohols and phenols with HMDS. Imidazole- as well as N-methyl-2-pyrrolidone-based acidic ionic liquids have a higher catalytic activity for the protection of sensitive, hindered alcohols and phenols, thus providing an environmentally begin and versatile alternative to current acid catalysts. In addition, the acidic ionic liquids are reusable, being recovered easily and reused several times without significant deterioration in catalytic activity.
Introduction of PEG-SANM nanocomposite as a new and highly efficient reagent for the promotion of the silylation of alcohols and phenols and deprotection of the silyl ethers
Shirini, Farhad,Shojaei, Abdollah Fallah,Heirati, Seyedeh Zahra Dalil
, p. 944 - 951 (2016/07/06)
Poly (ethylene glycol)-sulfonated sodium montmorillonite (PEG-SANM) nanocomposite was prepared by a simple method and characterized using XRD, TGA, SEM, TEM, and FT-IR techniques. After preparation and characterization, this reagent was used as a highly efficient and reusable solid acid catalyst for the chemoselective silylation of alcohols and phenols and deprotection of the obtained silyl ethers. Themethod offers several advantages including high to excellent yields of the products, short reaction times, easy preparation of the catalyst and easy work-up procedure. In addition, the catalyst can be recycled and reused at least for five times without significant decrease in the catalytic activity.
