- Bonding interactions in uranyl α-diimine complexes: A spectroscopic and electrochemical study of the impacts of ligand electronics and extended conjugation
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Uranyl complexes of aryl-substituted α-diimine ligands gbha (UO2-1a-f) and phen-BIAN (UO2-2a-f) [gbha (1) = glyoxal bis(2-hydroxyanil); phen-BIAN (2) = N,N′-bis(iminophenol)acenaphthene; R = OMe (a), t-bu (b), H (c), Me (d), F (e), a
- Niklas, Julie E.,Hunter, Katherine M.,Gorden, Anne E. V.
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- Reaction of 1,5-dimethyl-2,3,3,4-tetrachloro-1,5,2,4-diazadiphosphorinan-6- one with aniline derivatives, heptamethyldisilazane and tert.-butylamine: Oxidative addition of tetrachloro-o-benzoquinone to some P(III)-containing products
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The reaction of the title compound 1 with the p-R-aniline derivatives (R=H, F, OCH3, NO2, and NH2) led to the formation of the aza-2σ3, 4σ3-diphosphetidines 2a-2e, whereas 2-trimethylsiloxyaniline fur
- Krill, Jochen,Shevchenko, Igor V.,Fischer, Axel,Jones, Peter G.,Schmutzler, Reinhard
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- Synthesis and structural features of N-[(2-(trimethylsilyl)oxy)phenyl]-arylsulfonamides
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N-[(2-(Trimethylsilyl)oxy)phenyl]-4-methylbenzenesulfonamide and N-[(2-trimethylsilyloxy)phenyl]-4-chlorobenzenesulfonamide were prepared by two different methods. Their structures were studied by X-ray single-crystal analysis and DFT calculations includi
- Nikonov, Alexey Yu,Sterkhova, Irina V.,Serykh, Valeriy Yu,Kolyvanov, Nikita A.,Lazareva, Natalya F.
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- 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
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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).
- Mohammadiyan, Esmaeel,Ghafuri, Hossein,Kakanejadifard, Ali
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p. 171 - 178
(2018/09/12)
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- Pos [...] 4 group metal olefin polymerization catalyst
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Embodiments are directed to phosphaguanidine metal complexes of formula I and using those complexes in α-olefin polymerization systems.
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Paragraph 0506-0508
(2019/08/27)
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- Nano Fe3O4@ZrO2/SO42?: A highly efficient catalyst for the protection and deprotection of hydroxyl groups using HMDS under solvent-free condition
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In this work, we introduce a new procedure for the protection and deprotection process of various types of alcohols and phenols by HMDS in the presence of nano magnetic sulfated zirconia (Fe3O4@ZrO2/SO42?) as a solid acid catalyst under very mild and solvent-free condition. This method has interesting advantages like short reaction times and a simple workup process. With regard to some outstanding benefits of this new heterogeneous catalyst such as excellent yield, reusability of the catalyst and easy thermal stability, high acidity, strong and excellent magnetic properties, this method can be very interesting in aspect of green chemistry Principles.
- Ghafuri, Hossein,Paravand, Fatemeh,Rashidizadeh, Afsaneh
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supporting information
p. 129 - 135
(2016/12/24)
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- Chlorozincate(II) acidic ionic liquid: Efficient and biodegradable silylation catalyst
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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.
- Abbasi, Faezeh,Azizi, Najmedin,Abdoli-Senejani, Masumeh
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- 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
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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.
- Seddighi, Mohadeseh,Shirini, Farhad,Goli-Jolodar, Omid
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p. 23564 - 23570
(2016/03/12)
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- Nanomagnetic zirconia-based sulfonic acid (Fe3O4@ZrO2-Pr-SO3H): A new, efficient and recyclable solid acid catalyst for the protection of alcohols: Via HMDS under solvent free conditions
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In the present work, sulfonic acid functionalized nanomagnetic zirconia is prepared by the reaction of (3-mercaptopropyl)trimethoxysilane and nanomagnetic zirconia. Then, nanomagnetic zirconia-based sulfonic acid (Fe3O4@ZrO2/su
- Tadjarodi, Azadeh,Khodikar, Rahim,Ghafuri, Hosssein
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p. 63480 - 63487
(2016/07/19)
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- RuIII(OTf)SalophenCH2-NHSiO2-Fe: An efficient and magnetically recoverable catalyst for trimethylsilylation of alcohols and phenols with hexamethyldisilazane
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Efficient trimethylsilylation of alcohols and phenols with hexamethyldisilazane (HMDS) catalyzed by ruthenium(III) complex of chloromethylated Salophen supported on nanomagnetic materials is reported. First, the iron nanomagnets were silica coated, functi
- Torki, Maryam,Tangestaninejad, Shahram,Mirkhani, Valiollah,Moghadam, Majid,Mohammadpoor-Baltork, Iraj
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p. 304 - 309
(2014/04/03)
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- A survey of pendant donor-functionalised (N,O) phosphine ligands for Cr-catalysed ethylene tri- and tetramerisation
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In this study three classes of ligands are explored for ethylene tri-/tetramerisation in conjunction with chromium and both triethylaluminium (AlEt3) and methylaluminoxane (MAO) co-catalysts. Hydrazine based ligands containing an N-H functionality [PN(NH)P], analogous to Rosenthal's previously reported PNPNH system, show selectivity towards 1-hexene and 1-octene formation in conjunction with AlEt3, and act as PNP tetramerisation analogues when MAO is employed. PNP ligands containing non-protic pendant donor moieties generally show poor activity and selectivity when AlEt3 is employed as an activator, however when MAO is used good activities and selectivities are achieved. n-Propylcyclopentane and 2-propenylcyclopentane, and higher homologues, are produced during catalysis when oxygen is the donor atom. The formation of such products is discussed with respect to the generation of methylenecyclopentane and methylcyclopentane by PNP based tetramerisation catalysts. Simple phosphine ligands containing O-H functionalisation are also explored and it was shown that the catalyst selectivity is highly dependent on both the activator and structural features of the ligand employed.
- Suttil, James A.,Wasserscheid, Peter,McGuinness, David S.,Gardiner, Michael G.,Evans, Stephen J.
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p. 2574 - 2588
(2014/07/22)
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- Preparation, characterization and use of 1,3-disulfonic acid imidazolium hydrogen sulfate as an efficient, halogen-free and reusable ionic liquid catalyst for the trimethylsilyl protection of hydroxyl groups and deprotection of the obtained trimethylsilanes
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Novel 1,3-disulfonic acid imidazolium hydrogen sulfate, a halogen-free ionic liquid, is a recyclable and eco-benign catalyst for the trimethylsilyl protection of hydroxyl groups at room temperature under solvent free conditions to afford trimethylsilanes in excellent yields (92-100%) and in very short reaction times (1-5 min). Deprotection of the resulting trimethylsilanes can also be achieved using the same catalyst in methanol. The catalyst was characterized by IR, 1H NMR, 13C NMR and MS studies. All the products were extensively characterized by IR, 1H NMR, MS, and elemental and melting point analyses. This new method consistently has the advantages of excellent yields and short reaction times. Further, the catalyst can be recovered and reused for several times without loss of activity. The work-up of the reaction consists of a simple separation, followed by concentration of the crude product and purification.
- Shirini, Farhad,Khaligh, Nader Ghaffari,Akbari-Dadamahaleh, Somayeh
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- Poly(4-vinylpyridine) catalyzed chemoselective O-TMS protection of alcohols and phenols and N-Boc protection of amines
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Poly(4-vinylpyridine) (PVP) acts as an efficient and reusable catalyst for the selective and efficient trimethylsilylation of alcohols and phenols with hexamethyldisilazane (HMDS) and N-tert-butoxycarbonylation of amines with (Boc)2O. All reactions were performed under mild conditions in good to high yields. Iranian Chemical Society 2012.
- Shirini, Farhad,Khaligh, Nader Ghaffari
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p. 495 - 502
(2013/02/22)
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- Preparation, characterization and use of 3-methyl-1-sulfonic acid imidazolium hydrogen sulfate as an eco-benign, efficient and reusable ionic liquid catalyst for the chemoselective trimethylsilyl protection of hydroxyl groups
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New and novel ionic liquid (3-methyl-1-sulfonic acid imidazolium hydrogen sulfate) is a recyclable and eco-benign catalyst for the chemoselective trimethylsilyl protection of hydroxyl groups under solvent-free conditions to afford trimethylsilanes in excellent yields (92-100%) and in very short reaction times (1-8 min). The catalyst was characterized by FT-IR, 1H NMR and 13C NMR studies. All the products were extensively characterized by 1H NMR, IR, GC-MS and melting point analyses. A mechanism for the catalytic activity is proposed. The catalyst can be recovered and reused without loss of activity. The work-up of the reaction consists of a simple separation, followed by concentration of the crude product and purification.
- Khaligh, Nader Ghaffari
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experimental part
p. 63 - 70
(2011/12/02)
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- Tetrabutylammonium phthalimide-N-oxyl: An efficient organocatalyst for trimethylsilylation of alcohols and phenols with hexamethyldisilazane
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Tetrabutylammonium phthalimide-N-oxyl (TBAPINO) was found to be an effective organocatalyst for rapid, simple and chemoselective protection of the hydroxyl group of alcohols and phenols using hexamethyldisilazane (HMDS) under mild conditions. The low catalyst loading, high to quantitative yields and simple removal of the catalyst from the reaction mixture illustrate the other attractive features of this protocol.
- Dekamin,Yazdaninia,Mokhtari,Naimi-Jamal
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experimental part
p. 537 - 544
(2012/06/18)
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- Succinimide-N-sulfonic acid: A mild, efficient, and reusable catalyst for the chemoselective trimethylsilylation of alcohols and phenols
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Succinimide-N-sulfonic acid (SuSA) is easily prepared by the reaction of succinimide with chlorosulfonic acid. This reagent is able to efficiently catalyze the chemoselective trimethylsilylation of alcohols and phenols with hexamethyldisilazane (HMDS). All reactions were performed under mild reaction conditions, giving excellent yields. Copyright Taylor & Francis Group, LLC.
- Shirini,Khaligh, Nader Ghaffari
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experimental part
p. 2156 - 2165
(2012/04/10)
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- NOVEL SULFONAMIDE DERIVATIVE
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A compound of the formula (1): wherein m, n and p is independently an integer of 0 to 4 with the proviso that 3 a?| m + n a?| 8; X is the formula: NR4, etc.; R1, R3 and R4 are a substituted or unsubstituted aryl group, etc.; R2 is a hydrogen atom, etc.; a, b, c, d, e and f are a hydrogen atom or a substituted or unsubstituted alkyl group, etc.; Y is the formula: -SO2-, etc.; and Z is an oxygen atom, etc.; or a prodrug thereof or a pharmaceutically acceptable salt of the same has an activity of potentiating an expression of a low density lipoprotein receptor and thus is useful as an agent for treating hyperlipidemia or arteriosclerosis.
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Page/Page column 51
(2010/11/25)
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- A study of ortho- and para-siloxyanilines for the synthesis of mono-, bi-, and tetra-nuclear early transition metal-imido complexes
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The siloxyanilines o-Me3SiOC6H4NH2 (1) and p-RMe2SiOC6H4NH2 (R = H (2); R = Me (3)), and their N-silylated derivatives p-Me3SiOC6H4NHS
- Benito,Arévalo, Silvia,De Jesús,De La Mata,Flores,Gómez
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- Fluorophosphoranes as Lewis acids. The conditions of access to hexacoordinated neutral adducts via the intramolecular addition of an electrondonor
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The possibility of obtaining bicyclic neutral hexacoordinated fluorophosphorus adduct of type 2 was investigated for R=F, Me, Ph and X=O, S, NH, NMe, NtBu NPh.Adduct 2g was formed predominantly only in the case where R=F and X=S.In all the othe
- Robert, Dominique,Gawad, Hoda Abdel,Riess, Jean G.
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p. 511 - 516
(2007/10/02)
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- Drug Latentiation by γ-Glutamyl Transpeptidase
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The N-γ-glutamyl derivatives of L-thiazolidine-4-carboxylic acid, 4-aminobutyric acid, 1-aminocyclopentanecarboxylic acid, 2-aminophenol, and p-fluoro-L-phenylalanine (compounds 6, 8, 9, 10, and 12 respectively) were synthesized using the synthom phthaloylglutamic anhydride.Their relative rates of cleavage by the enzyme γ-glutamyl transpeptidase (γ-GT) were determined in order to evaluate the possibility for their selective release by this enzyme which is elevated in certain pathological conditions.Compounds 6, 8, and 9 were not readily solvolyzed by γ-GT, but compounds 10 and 12, as well as the N-γ-glutamylated derivatives of 3- and 4-aminophenol, were readily cleaved.
- Magnan, Sanne D. J.,Shirota, Frances N.,Nagasawa, Herbert T.
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p. 1018 - 1021
(2007/10/02)
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