14856-74-7Relevant academic research and scientific papers
An asymmetric Salamo-based Zn complex supported on Fe3O4MNPs: a novel heterogeneous nanocatalyst for the silyl protection and deprotection of alcohols under mild conditions
Yao, Hongyan,Wang, Yongsheng,Razi, Maryam Kargar
, p. 12614 - 12625 (2021/04/14)
In this study, a magnetic asymmetric Salamo-based Zn complex (H2L = salen type di-Schiff bases)-supported on the surface of modified Fe3O4(Fe3O4@H2L-Zn) as a new catalyst was designed and characterizedvianumerous analytical techniques such as FT-IR spectroscopy, XRD, EDS, ICP-AES, SEM, TEM, TGA and VSM. An efficient and sustainable synthetic protocol has been presented for the synthesis of silyl ether substructuresviathe silyl protection of alcohols under mild conditions. The synthetic protocol involves a two-component solvent-free reaction between various hydroxyl-bearing substrates and hexamethyldisilazane (HMDS) as an inexpensive silylating agent using Fe3O4@H2L-Zn MNPs as a magnetically separable, recyclable and reusable heterogeneous catalyst. Fe3O4@H2L-Zn MNPs were also applied for the removal of silyl protecting groups from hydroxyl functions using water in CH2Cl2under green conditions. The catalyst demonstrated good to excellent catalytic yield efficiency for both the reactions compared to the commercial metal-based catalysts under green conditions for a wide range of substrates.
KF/clinoptilolite NPs: An efficient and heterogeneous catalyst for chemoselective silylation of alcohols and phenols
Oladee, Razieh,Zareyee, Daryoush,Khalilzadeh, Mohammad A.
, p. 731 - 737 (2021/03/31)
Potassium fluoride incorporated on clinoptilolite nanoparticles (KF/CP NPs) by ion exchanging is found to be an effective and inexpensive heterogeneous nanocatalyst for chemoselective silylation of alcohols and phenols with 1,1,1,3,3,3-hexamethyldisilazane (HMDS) at room temperature. Nano-powder of clinoptilolite (CP) was prepared using a planetary ball mill mechanically method and characterized by dynamic light scattering (DLS), X-ray powder diffraction (XRD) and scanning electron microscope (SEM) analyses. Almost all of products were obtained in high yields as well as short reaction times and the catalyst was also reused eight times without loss of its catalytic activity.
Synthesis and characterization of a bifunctional nanomagnetic solid acid catalyst (Fe3O4@CeO2/SO42?) and investigation of its efficiency in the protection process of alcohols and phenols via hexamethyldisilazane under solvent-free conditions
Mohammadiyan, Esmaeel,Ghafuri, Hossein,Kakanejadifard, Ali
, p. 171 - 178 (2018/09/12)
In this research, Fe3O4@CeO2 (FC) was synthesized using the coprecipitation method and functionalized by an ammonium sulfate solution to achieve a heterogeneous solid acid Fe3O4@CeO2/SO42? (FCA) catalyst. The synthesized bifunctional catalyst was used in the protection process of alcohols and phenols using hexamethyldisilazane (HMDS) at ambient temperature under solvent-free conditions. Due to its excellent magnetic properties, FCA can easily be separated from the reaction mixture and reused several times without significant loss in its catalytic activity. Excellent yield and selectivity, simple separation, low cost, and high recyclability of the nanocatalyst are outstanding advantages of this procedure. The characterization was carried out using different techniques such as Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and vibrating sample magnetometry (VSM).
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.
A simple and efficient room temperature silylation of diverse functional groups with hexamethyldisilazane using CeO2 nanoparticles as solid catalysts
Anbu, Nagaraj,Vijayan, Chellappa,Dhakshinamoorthy, Amarajothi
, (2019/06/08)
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.
Fast and efficient method for Silylation of alcohols and phenols with HMDS in the presence of bis-thiourea complexes of cobalt, nickel, copper and zinc chlorides
Zeynizadeh, Behzad,Sorkhabi, Serve
, p. 127 - 135 (2018/02/06)
Bis-thiourea complexes of cobalt, nickel, copper and zinc chlorides were used efficiently for rapid and efficient trimethylsilylation of alcohols and phenols with hexamethyldisilazane (HMDS) in CH3CN. All reactions were carried out at room temperature within immediate-120?min timeframe to afford trimethylsilyl ether derivatives in high to excellent yields. Investigation of the results exhibited that the prepared bis-thiourea metal complexes show the activity as Co(tu)2Cl2> Ni(tu)2Cl2> Cu(tu)2Cl2> Zn(tu)2Cl2 in their silylation reactions.
Graphene oxide-bound electron-deficient tin(IV) porphyrin: a highly efficient and selective catalyst for trimethylsilylation of alcohols and phenols with hexamethyldisilazane
Zarrinjahan, Alireza,Moghadam, Majid,Mirkhani, Valiollah,Tangestaninejad, Shahram,Mohammadpoor-Baltork, Iraj
, (2017/02/05)
The catalytic activity of graphene oxide-bound tetrakis(p-aminophenyl)porphyrinatotin(IV) trifluoromethanesulfonate, [SnIV(TNH2PP)(OTf)2], in the trimethylsilylation of alcohols and phenols with hexamethyldisilazane (HMDS) is reported. The prepared catalyst was characterized using inductively coupled plasma analysis, scanning electron microscopy, transmission electron microscopy, and Fourier transform infrared and diffuse reflectance UV–visible spectroscopies. This heterogeneous catalyst was used for selective trimethylsilylation of various alcohols and phenols with HMDS in short reaction times and high yields. Also, the catalyst is of high reusability and stability, in that it was recovered several times without loss of its initial activity. The chemoselectivity of this catalytic system in the silylation of primary alcohols in the presence of secondary and tertiary alcohols and also phenols was investigated.
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
supporting information, 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.
Preparation and characterization of a RHA/TiO2 nanocomposite: Introduction of an efficient and reusable catalyst for chemoselective trimethylsilyl protection and deprotection of alcohols and phenols
Seddighi, Mohadeseh,Shirini, Farhad,Goli-Jolodar, Omid
, p. 23564 - 23570 (2016/03/12)
In this work, rice husk ash (RHA), as a natural source of amorphous silica, was used as a support for the synthesis of anatase-phase titania nanoparticles leading to the RHA/TiO2 nanocomposite. This nanocomposite was used as an efficient catalyst for the chemoselective trimethylsilylation of various alcohols and phenols and deprotection of the obtained trimethylsilyl ethers. The procedure gave the products in excellent yields in very short reaction times. Also this catalyst can be reused at least six times without loss of its catalytic activity.
