3768-55-6Relevant articles and documents
Formation of Aromatic O-Silylcarbamates from Aminosilanes and Their Subsequent Thermal Decomposition with Formation of Isocyanates
Gründler, Franziska,Herbig, Marcus,Kroke, Edwin,Scholz, Henrik,Schwarzer, Sandra,Wagler, J?rg
, p. 2211 - 2224 (2021/06/11)
A novel phosgene-free route to different isocyanates starts from CO2 and aminosilanes (cf. silylamines) to form so-called carbamoyloxysilanes (O-silylcarbamates), i. e., compounds with the general motif R1R2N?CO?O?SiR3R4R5 as potential precursors. We focused on the insertion reaction of CO2 into Si?N bonds of substrates with cyclic (mostly aromatic) amine substituents, i. e., PhNHSiMe3, (PhNH)2SiMe2, PhCH2NHSiMe3, p-(MeO)C6H4NHSiMe3, o-C6H4(NHSiMe3)2, 1,2-C6H10(NHSiMe3)2, o-C6H4(NHSiMe3)(CH2NHSiMe3) and 1,8-C10H6(NHSiMe3)2. Compared to previously investigated aminosilanes these reactions are hindered due to the reduced nucleophilicity/basicity of the N-atoms. Whereas slightly increased CO2 pressure (8 bar) and prolonged reaction times (24 h) were sufficient to overcome hindrance of the insertion into, e. g., PhNHSiMe3, intermolecular effects in some two-fold NHSiMe3 functionalized substrates led to partial mono-insertion (e. g., into o-C6H4(NHSiMe3)(CH2NHSiMe3)) or intra-molecular condensation of the intermediate insertion product in case of 1,8-C10H6(NHSiMe3)2 to form 1H-perimidin-2(3H)-one and other side products. Thermal treatment of mono-silylated O-silylcarbamates RHN?CO?O?SiR’3 resulted mainly in the formation of substituted ureas (RHN)2CO, whereas desired isocyanates could not be detected in these cases. Therefore, we continued our studies focussing on N,O-bissilylated precursors, which were obtained by an additional N-silylation of the O-silylated carbamates. This allowed the successful formation of isocyanates. As a sole byproduct hexamethyldisiloxane is formed. In all cases, known as well as yet unknown substances were characterised by 1H, 13C and 29Si NMR spectroscopy, along with X-ray diffraction analysis for crystallized solids.
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.
Trimethylsilyl-Induced N-O Bond Cleavage in Nitrous Oxide-Derived Aminodiazotates
Liu, Yizhu,Eymann, Léonard Y. M.,Solari, Euro,Fadaei Tirani, Farzaneh,Scopelliti, Rosario,Severin, Kay
, p. 11859 - 11863 (2018/09/25)
The chemical activation of nitrous oxide (N2O) typically results in O-atom transfer and the extrusion of N2 gas. In contrast, reactions of N-trimethylsilyl (TMS)-substituted amides with N2O give inorganic or organic azides
Insertion of phenyl isocyanate into monoand diaminosilanes
Kraushaar, Konstantin,Herbig, Marcus,Schmidt, Dana,Wagler, J?rg,B?hme, Uwe,Kroke, Edwin
, p. 909 - 921 (2018/01/19)
The aminosilanes MenSi(NRR')4-n (n = 2,3) with NRR' = ethylamino (NHEt), n-propylamino (NHnPr), sec-butylamino (NHsBu), n-octylamino (NHnOct), n-dodecylamino (NHnDodec), allylamino (NHAll), tert-butylamino (NHtBu), diethylamino (NEt2), and anilino (NHPh) were synthesized and their reactions with phenyl isocyanate were studied. In all cases of these silanes Me3SiNRR' and Me2Si(NRR')2 formal insertion of the -NCO group into their Si-N bonds was observed, i.e. formation of products with Si-N (rather than Si-O) bonds was found. In some cases, the products could be crystallized and their molecular structures have been elucidated with single-crystal X-ray diffraction analyses.
Ruthenium-catalyzed dealkenative N-silylation of amines by substituted vinylsilanes
Marciniec, Bogdan,Kostera, Sylwia,Wyrzykiewicz, Bozena,Pawlu, Piotr
supporting information, p. 782 - 786 (2015/02/19)
The ruthenium hydride complex-catalyzed N-silylation of primary and secondary amines with substituted vinylsilanes, with the general formula R1CHCHSiR′3 (where R1 = H, Ph, n-Bu, Si(OEt)3), leading to the formation of a Si-
Synthesis of 1,3-dichloro- cyclo -1,3-diphosphadiazanes from silylated amino(dichloro)phosphanes
Schulz, Axel,Villinger, Alexander,Westenkirchner, Andrea
supporting information, p. 11457 - 11468 (2013/10/22)
The synthesis of 1,3-dichloro-cyclo-1,3-diphosphadiazanes [ClP(μ-NR)]2 via elimination of Me3SiCl from silylated amino(dichloro)phosphanes, R-N(SiMe3)PCl2, was studied by different synthetic protocols starting from R-N(H)SiMe3 (R = Si(SiMe3)3 = Hyp, N(SiMe3)2, Mes* = 2,4,6-tri-tert-butylphenyl, Ter = 2,4-bis(2,4,6-trimethylphenyl) phenyl, Dipp = 2,6-diisopropylphenyl, Dmp =2,6-dimethylphenyl, Ad = Adamantyl, Trityl = Ph3C, Tos = tosyl = CH3C6H 4SO2, n-Oct = n-octyl, and Me3Si). A new synthetic route using trimethylsilyl-substituted amino(dichloro)phosphanes, R-N(SiMe3)PCl2, was developed to form cyclo-diphosph(III)- azanes simply by adding a mixture of RfOH/base (RfOH = hexafluoroisopropanole). By this method electron-rich/-poor aryl-, silyl-, and bissilylamino-substituted cyclo-diphosph(III)-azanes are accessible such as the unprecedented (Me3Si)2N-substituted species [ClP(μ-NN(SiMe3)2)]2 starting from tris(trimethylsilyl)hydrazine and PCl3. Additionally, the difficulties with the preparation of cyclo-diphosphadiazanes depending on the starting materials, solvents, and bases due to the competition of different reaction channels are studied.
A highly facile approach to the synthesis of novel 2-(3-benzyl-2,4-dioxo-1, 2,3,4-tetrahydropyrimidin-1-yl)-N-phenylacetamides
Novikov, Mikhail S.,Babkov, Denis A.,Paramonova, Maria P.,Chizhov, Alexander O.,Khandazhinskaya, Anastasia L.,Seley-Radtke, Katherine L.
supporting information, p. 576 - 578 (2013/02/23)
A series of heterocyclic compounds were designed as potential nonnucleoside HIV reverse transcriptase inhibitors. Although the compounds ultimately proved inactive against HIV, during the course of the synthesis, a new and highly facile method to realize N-phenylacetamides was developed. Notably, the new route avoids the intractable workups and byproducts previously reported procedures have been associated with, thereby making this approach highly attractive to adaptation with other heterocyclics.
Iron-catalyzed aromatic amination for nonsymmetrical triarylamine synthesis
Hatakeyama, Takuji,Imayoshi, Ryuji,Yoshimoto, Yuya,Ghorai, Sujit K.,Jin, Masayoshi,Takaya, Hikaru,Norisuye, Kazuhiro,Sohrin, Yoshiki,Nakamura, Masaharu
supporting information, p. 20262 - 20265 (2013/02/23)
Novel iron-catalyzed amination reactions of various aryl bromides have been developed for the synthesis of diaryl- and triarylamines. The key to the success of this protocol is the use of in situ generated magnesium amides in the presence of a lithium halide, which dramatically increases the product yield. The present method is simple and free of precious and expensive metals and ligands, thus providing a facile route to triarylamines, a recurrent core unit in organic electronic materials as well as pharmaceuticals.
Cu(NO3)2 · 3 H2O as an efficient reagent for the chemoselective trimethylsilylation of primary alcohols and oxidation of trimethylsilyl ethers
Shirini,Mashhadi-Nejad
experimental part, p. 376 - 381 (2012/04/04)
Cu(NO3)2 · 3 H2O can be used as an efficient reagent for the chemoselective trimethylsilylation of primary benzylic and aliphatic alcohols with hexamethyldisilazane (HMDS). This reagent is also able to oxidize the obtained trimethylsilyl ethers to the corresponding carbonyl compounds in the presence of wet SiO2 and KBr. In this study, all reactions are performed in the absence of a solvent and good-to-high yields are obtained.
N-bonded monosilanols: Synthesis and characterization of ArN(SiMe 3) SiMe2Cl and ArN(SiMe3)SiMe2OH (Ar = C6H5, 2,6-Me2C6H3, 2,6-iPr2C6H3)
Chandrasekhar, Vadapalli,Boomishankar, Ramamoorthy,Azhakar, Ramachandran,Gopal, Kandasamy,Steiner, Alexander,Zacchini, Stefano
, p. 1880 - 1885 (2007/10/03)
By the use of aniline and the sterically hindered aromatic primary amines, 2,6-Me2C6H3NH2 and 2,6-iPr 2C6H3NH2, N-bonded monochlorosilanes, ArN(SiMe3)SiMe2Cl [Ar = C 6H5 (1a), Ar = 2,6-Me2C6H 3 (1b) and Ar = 2,6-iPr2C6H3 (1c)] have been prepared by a sequential deprotonation at the nitrogen followed by reaction with silyl chlorides. Hydrolysis of the N-bonded monochlorosilanes afforded the N-bonded monosilanols ArN(SiMe3)SiMe2OH [Ar = C6H5 (2a), Ar = 2,6-Me2C6H 3 (2b) and Ar = 2,6-iPr2C6H3 (2c)]. The X-ray crystal structure of le reveals a positional disorder of the Cl and CH3 substituents on silicon. The X-ray crystal structure of 2c shows that it is involved in an intermolecular O-H...O hydrogen bonding in the solid state to afford a dimeric structure containing the O2H 2 ring. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.