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1.
O. V. Andreev M. N. Bochkarev T. V. Nekrasova A. V. Protchenko 《Russian Chemical Bulletin》1995,44(2):233-235
X-ray amorphous samarium(II) sulfide was prepared by the reaction of H2S with samarium(II) bis[bis(trimethylsilyl)amide] (1) in THF at 10–2 Torr. Compound1 was prepared by two methods: 1) the reaction of SmI2 with lithium bis(trimethylsilyl)amide and 2) the reaction of samarium naphthalide with bis(trimethylsilyl)amine. SmS was transformed to the polycrystalline state with the lattice parametera = 5.92 Å by annealing at 400–500 °C.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 241–243, February, 1995. 相似文献
2.
Qibao Wang Ruifang Ding Xinmin Wen Fujun Yin 《Phosphorus, sulfur, and silicon and the related elements》2013,188(7):895-903
Abstract Four diorganotin(IV) complexes, bis[(trimethylsilyl)methyl]tin salicylaldehyde thiosemicarbazonate monohydrate(1), bis[(trimethylsilyl)methyl]tin 3-methoxysalicylaldehyde thiosemicarbazonate (2), bis[(trimethylsilyl)methyl]tin 5-tert-butyl-3-methylsalicylaldehyde thiosemicarbazonate (3), and bis[(trimethylsilyl)methyl]tin 2-oxylnaphthaldehyde thiosemicarbazonate (4) have been synthesized by reactions of (Me3SiCH2)2SnCl2 with the corresponding semicarbazone. The four complexes were characterized by IR and NMR spectroscopy and elemental analyses. The X-ray studies of compounds 1 and 4 showed that the thiosemicarbazone ligands act as tridentate ligands chelating to the central tin atoms, and thus the tin atoms were five coordinated in trigonal bipyramidal geometry for both compounds. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. 相似文献
3.
Gabriele Kociok-Köhn Gareth J. Price Douglas R.G. Smith 《Supramolecular chemistry》2013,25(8):697-707
The structures of the silylated DNA bases, bis(trimethylsilyl)thymine (1), bis(trimethylsilyl)cytosine (2), bis(trimethylsilyl)adenine (3) and tris(trimethylsilyl)guanine (4), have been determined. 1 is O-silylated and displays no intermolecular interactions. 2 is silylated at both exocylic O, N positions and forms a chain structure through intermolecular NH…O and NH…N hydrogen bonds. 3 contains two SiMe3 groups, on the exocylic NH and endocyclic N9 position, respectively; of two independent molecules in the asymmetric unit, one dimerises through complementary NH…N hydrogen bonds, while the other forms a strained intramolecular hydrogen bond through the same pair of donor and acceptor centres. 4 incorporates N, N, O–SiMe3 moieties and forms chains via bifurcated CH…O/N hydrogen bonds, while the NH function remains unexploited. The effects of silylation on these pyrimidine and purine ring structures are also discussed in comparison with the native bases. The structures of the silylated DNA bases, bis-(trimethylsilyl)thymine (1), bis-(trimethylsilyl)cytosine (2), bis-(trimethylsilyl)adenine (3) and tris-(trimethylsilyl)guanine (4), have been determined. While 1 displays no intermolecular interactions. 2 forms a chain structure through intermolecular NH…O and NH…N hydrogen bonds, 3 incorporates two independent molecules in the asymmetric unit, one dimerises through complementary NH…N hydrogen bonds while the other forms a strained intramolecular hydrogen bond through the same pair of donor and acceptor centres and 4 forms chains via bifurcated CH…O/N hydrogen bonds while the NH function remains unexploited. 相似文献
4.
Norihiro Tokitoh Kazuto Nagata Nobuhiro Takeda 《Phosphorus, sulfur, and silicon and the related elements》2013,188(4-5):915-927
The reactions of overcrowded platinum(0) complexes [Pt{P(Ar)Me2}2] (Ar = 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl (Tbt), 2,6-bis[bis- (trimethylsilyl)methyl]-4-[tris(trimethylsilyl)methyl]phenyl (Bbt)) with elemental sulfur and selenium resulted in the formation of the first platinum disulfur and diselenium complexes, [Pt(S2){P(Ar)Me2}2] (4a (Ar = Tbt), 4b (Ar = Bbt) and [Pt(Se2){P(Ar)Me2}2] (5a (Ar = Tbt), 5b (Ar = Bbt)) respectively. The x-ray crystallographic analyses of 4b and 5b showed a novel three-membered PtE2 (E = S, Se) ring structure with a square planar geometry around the platinum center. The oxidation of 4b and 5b with an equimolar amount of m-chloroperbenzoic acid or tert-butyl hydroperoxide in dichloromethane yielded the corresponding disulfur and diselenium monoxide complexes [Pt(E2O){P(Bbt)Me2}2] (6 (E = S), 7 (E = Se)). The further reactions of 6 and 7 with an excess of oxidants gave the corresponding O,S-coordinated thiosulfato complex [Pt(S2 O3){P(Bbt)Me2}2] (8) and the O,O-coordinated selenito complex [Pt(SeO3){P(Bbt)Me2}2] (11), respectively. The dynamic behavior in solution was revealed by the variable-temperature NMR spectroscopy for 4b, 5b, 8, and 11, which indicates the existence of the intramolecular CH···E (E = O, S, Se) interactions between the methine hydrogens of the o-bis(trimethylsilyl)methyl groups and the Pt-bonded chalcogen atoms. 相似文献
5.
《Analytical letters》2012,45(12):799-806
Abstract Selenium can be chromatographed after the formation of the trimethylsilyl derivative. The TMSi derivative was formed from the ammonium salt of selenic acid by ion exchange on a cation exchange column. The eluted species was identified by mass spectrometry as SeO2(TMSi)2 相似文献
6.
Moncef Bellassoued Et Margarita Mladenova 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3-4):295-301
Abstract Bis(trimethylsilyl) ketene acetals RCH[dbnd]C[OSi(CH3)3]2 1 add to PhCH[dbnd]CH[sbnd]COR1 2 in the presence of catalytic amounts (10%) of TiCl4 leading, in good to excellent yields to the corresponding β-hydroxy or δ-ketoacids. Under kinetic control, the regioselectivity of the reaction markedly depends on the nature of R and R1. Mixtures of 1,2 and 1,4 products are formed in some of the cases; in others, solely Michael or aldol adducts are obtained. On the contrary, the stereoselectivity, which ranges from zero to moderate, is slightly influenced by R and R1. It is also shown that trimethylsilyl ester of α-trimethylacetic acid (CH3)3SiCH2CO2Si(CH3)3 5 add to 2 in the presence of TBAF (10%) in THF. 相似文献
7.
Yukihiro Isogai Tomoko Kawase Hideharu Ishida Makoto Kiso Akira Hasegawa 《Journal of carbohydrate chemistry》2013,32(8):1001-1023
ABSTRACT 3-O-Sulfo glucuronyl paragloboside derivatives (pentasaccharides) have been synthesized. The important intermediate designed for a facile sulfation in the last step and effective, stereocontrolled glycosidation, methyl (4-O-acetyl-2-O-benzoyl-3-O-levulinoyl-α-D-glucopyranosyl trichloroacetimidate)uronate (8) was prepared from methyl [2-(trimethylsilyl)ethyl β-D-glucopyranosid]uronate (3) via selective 4-O-acetylation, 2-O-benzoylation, 3-O-levulinoylation, removal of the 2-(trimethylsilyl)ethyl group and imidate formation. The glycosylation of 8 with 2-(trimethylsilyl)ethyl 2,4,6-tri-O-benzyl-β-D-galactopyranoside (9) using trimethylsilyl trifluoromethanesulfonate gave 2-(trimethylsilyl)ethyl O-(methyl 4-O-acetyl-2-O-benzoyl-3-O-levulinoyl-β-D-glucopyranosyluronate)-(1→3)-2,4,6-tri-O-benzyl-β-D-galactopyranoside (10), which was transformed via removal of the benzyl group, benzoylation, removal of the 2-(trimethylsilyl)ethyl group and imidate formation into the disaccharide donor 13. On the other hand, 2-(trimethylsilyl)ethyl O-(2-acetamido-3,6-di-O-benzyl-2-deoxy-β-D-glucopyranosyl)-(1→3)-O-(2,4,6-tri-O-benzyl-β-D-galactopyranosyl)-(1→4)-2,3,6-tri-O-benzyl-β-D-glucopyranoside (20) as the acceptor was prepared from 2-(trimethylsilyl)ethyl 3,6-di-O-benzyl-2-deoxy-2-phthalimido-β-D-glucopyranoside (14) via O-acetylation, removal of the 2-(trimethylsilyl)ethyl group, imidate formation, coupling with 2-(trimethylsilyl)ethyl O-(2,4,6-tri-O-benzyl-β-D-galactopyranosyl)-(1→4)-2,3,6-tri-O-benzyl-β-D-glucopyranoside (18), removal of the O-acetyl and N-phthaloyl group followed by N-acetylation. Condensation of 13 with 20 using trimethylsilyl trifluoromethanesulfonate afforded the desired pentasaccharide 21, which was transformed by removal of the benzyl group, O-acetylation, removal of the 2-(trimethylsilyl)ethyl group and imidate formation into the pentasaccharide donor 24. Glycosylation of (2S,3R,4E)-2-azido-3-O-benzoyl-4-octadecene-1,3-diol (25) with 24 gave the desired β-glycoside 26, which was transformed into the four target compounds, via reduction of the azido group, coupling with octadecanoic acid or tetracosanoic acid, selective removal of the levulinoyl group, O-sulfation, hydrolysis of the methyl ester group and O-deacylation. 相似文献
8.
V. I. Kadentsev N. D. Chuvylkin A. A. Stomakhin N. G. Kolotyrkina O. S. Chizhov 《Russian Chemical Bulletin》1998,47(6):1228-1229
The equilibrium constants of trimethylsilyl cation transfer reactions differ from those of proton transfer reactions by many
orders of magnitude. The basicity of MeCN (1), MeNO2 (2), and Et2NH (3) in the gas phase decreases in the series3≫1>2, whereas the affinity of the same compounds for trimethylsilyl cation decreases in the series1≫3≈2. Semiempirical quantum-chemical MNDO calculations indicate that the formation of MeCN·SiMe3
+ ions is thermodynamically more favorable than that of MeNH2·SiMe3
+ ions.
Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 6, pp. 1260–1261, June, 1998. 相似文献
9.
A. R. Hajipour S. E. Mallakpour I. Mohammadpoor-baltork H. Adibi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):155-163
Abstract Benzyltriphenylphosphonium peroxomonosulfate (BnPh3P+HSO5 ?) (1) is used as a new reagent for oxidative deprotection of trimethylsilyl and tetrahydropyranyl ethers and ethylene acetals to afford carbonyl compounds in refluxing acetonitrile in the presence of bismuth chloride. 相似文献
10.
《Journal of carbohydrate chemistry》2013,32(1-2):113-122
A variety of functionalized pseudoglycal C-glycosides (C-pseudoglycals or C-hex-2-enopyranosides) have been obtained in excellent yield and stereoselectivity from the trimethylsilyl triflate (Me 3SiOTf) catalyzed reaction of trichloroacetimidate derivative 2 with silylated nucleophiles such as allyl and propargyl silanes and silyl enol ethers. 相似文献
11.
Abstract Ganglioside GM4 and GM3 analogs, containing 3-deoxy-D-glycero-D-galacto-2-nonulopyranosonic acid (KDN) in place of N-acetylneuraminic acid, have been synthesized. KDN, prepared by the condensation of oxalacetic acid with D-mannose, was converted into methyl (phenyl 4,5,7,8,9-penta-O-acetyl-3-deoxy-2-thio-D-glycero-D-galacto-2-nonulopyranosid)onate (2) via methyl esterification, O-acetylation and replacement of the anomeric acetoxy group with phenyl thio. Glycosylation of 2 with 2-(trimethylsilyl)ethyl 6-O-benzoyl-β-D-galactopyranoside (3) or 2-(trimethylsilyl)ethyl O-(6-O-benzoyl-β-D-galactopyranosyl)-(1→4)-2,6-di-O-benzoyl-β-D-glucopyranoside (4) was performed, using N-iodosuccinimide-trimethylsilyl trifluoromethanesulfonate as the glycosyl promoter, to give 2-(trimethylsilyl)ethyl O-(methyl 4,5,7,8,9-penta-O-acetyl-3-deoxy-D-glycero-α-D-galacto-2-nonulopyranosylonate)-(2→3)-6-O-benzoyl-β-D-galacto-pyranoside (5) and 2-(trimethylsilyl)ethyl O-(methyl 4,5,7,8,9-penta-O-acetyl-3-deoxy-D-glycero-α-D-galacto-2-nonulopyranosylonate)-(2→3)-(6-O-benzoyl-β-D-galactopyrano-syl)-(l→4)-(2,6-di-O-benzoyl-β-D-glucopyranoside (9), respectively. Compounds 5 and 9 were converted via O-acetylation, selective removal of the 2-(trimethylsilyl)ethyl group and subsequent imidate formation, into the corresponding trichloroacetimidates 8 and 12, respectively. Glycosylation of (2S,3R,4E)-2-azido-3-O-benzoyl-4-octadecene-l,3-diol (13) with 8 and 12 in the presence of boron trifluoride etherate afforded the expected β-glycosides 14 and 17, which were transformed via selective reduction of the azido group, coupling with octadecanoic acid, O-deacylation and de-esterification, into the target gangliosides 16 and 19 in high yields. 相似文献
12.
Akira Hasegawa Takatoshi Murase Hideharu Ishida Makoto Kiso 《Journal of carbohydrate chemistry》2013,32(4):589-596
Abstract Methyl [2-(trimethylsilyl)ethyl 5-acetamido-3,5-dideoxy-L-glycero-α-D-galacto-2-nonulopyranosid]onate (6) and its 8-epi-N-acetylneuraminic acid derivatives were synthesized from methyl [2-(trimethylsilyl)ethyl 5-acetamido-4,7-di-O-acetyl-3,5-dideoxy-D-glycero-α-D-galacto-2-nonulo-pyranosid]onate (1) and methyl [2-(trimethylsilyl)ethyl 5-acetamido-3,5-dideoxy-4,7-di-O-2-(trimethylsilyl)ethoxymethyl-D-glycero-α-D-galacto-2-nonulopyranosid]onate (2). 相似文献
13.
Eva Eichler Harold J. Jennings Dennis M. Whitfield 《Journal of carbohydrate chemistry》2013,32(4-5):385-411
Abstract We have synthesized a single repeat unit of type VIII Group B Streptococcus capsular polysaccharide, the structure of which is {L-Rhap(β1→4)-D-Glcp(β1→4)[Neu5Ac(α2→3)]-D-Galp(β→4)}n. The synthesis presented three significant synthetic challenges namely: the L-Rhap(β→4)-D-Glcp bond, the Neu5Ac(α2→3)-D-Galp bond and 3,4-D-Galp branching. The L-Rhap bond was constructed in 60% yield (α:β 1:1.2) using 4-O-acetyl-2,3-di-O-benzoyl-α-L-rhamnopyranosyl bromide 6 as donor, silver silicate as promotor and 6-O-benzyl-2,3-di-O-benzoyl-1-thio-β-D-glucopyranoside as acceptor to yield disaccharide 18. The Neu5Ac(α2→3) linkage was synthesized in 66% yield using methyl [phenyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-2-thio-D-glycero-D-galacto-nonulopyranosid]onate as donor and triol 2-(trimethylsilyl) ethyl 6-O-benzyl-β-D-galactopyranoside as acceptor to give disaccharide 21. The 3,4-D-Galp branching was achieved by regioselective glycosylation of disaccharide diol 21 by disaccharide 18 in 28% yield to give protected tetrasaccharide 22. Tetrasaccharide 22 was deprotected to give as its 2-(trimethylsilyl)ethyl glycoside the title compound 1a. In addition the 2-(trimethylsilyl)ethyl group was cleaved and the tetrasaccharide coupled by glycosylation (via tetrasaccharide trichloroacetimidate) to a linker suitable for conjugation. 相似文献
14.
Majid M. Heravi Dariush Ajami Kioumars Aghapoor Mitra Ghassemzadeh 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):151-156
Abstract A simple and selective oxidative deprotection of trimethylsilyl ethers to carbony1 compounds is described that occurs on PdCl2(PhCN)2-CrO3 and bis(trimethylsily1) chromate under solvent free conditions and is expedited by microwave irradiation. 相似文献
15.
Sonogashira coupling of (E)-α-iodovinylsilanes 1 with (trimethylsilyl)-acetylene gave (Z)-1,3-bis(trimethylsilyl)alk-3-en-1-ynes 2, which underwent a desilylation reaction to afford (Z)-3-(trimethylsilyl)alk-3-en-1-ynes 3 in good yields. (1E,3Z)-1-Arylseleno-3-(trimethylsilyl)-substituted 1,3-dienes 5 could be synthesized stereoselectively via hydrozirconation of (Z)-3-(trimethylsilyl)alk-3-en-1-ynes 3, followed by trapping with arylselenenyl bromides. 相似文献
16.
Huijun Liu Kailun He Jing Zhou 《Phosphorus, sulfur, and silicon and the related elements》2013,188(9):933-936
AbstractStrecker reaction of various substituted aromatic aldehydes, heteroaromatic aldehydes, aliphatic aldehydes and α,β-unsaturated aldehydes with trimethylsilyl cyanide (TMSCN) was realized in the presence of 5?mol % of MgI2 etherate in a mild, efficient and highly chemoselective manner under solvent-free conditions. 相似文献
17.
Kazem D. Safa Afsaneh Zeinolabedini Hassan Abbasi Reza Teimuri-Mofrad 《Journal of the Iranian Chemical Society》2013,10(3):447-452
A three-component efficient procedure is described for the synthesis of α-aminonitriles containing bis(trimethylsilyl)ethenyl groups from 4-[2,2-bis(trimethylsilyl)ethenyl]benzaldehyde (1), aromatic amines and trimethylsilyl cyanide (TMSCN). Reactions have been studied in the presence of various Lewis acids as catalysts or in ionic liquids under mild conditions. Compound (1) was obtained via Peterson olefination of terephthaldehyde with tris(trimethylsilyl)methyllithium, (Me3Si)3CLi, in THF at 0 °C. 相似文献
18.
《合成通讯》2013,43(21):3653-3660
Abstract Silica chloride (SiO2-Cl), as a heterogeneous reagent, has been used for the efficient dehydration of tertiary alcohols under mild reaction conditions. For comparison, we have also used trimethylsilyl chloride (TMSCl) as a homogeneous reagent for this purpose. We have found that silica chloride is a more efficient reagnet than trimethylsilyl chloride for this purpose. Handling of SiO2-Cl is much safer and easier than TMSCl, especially for large-scale operation. The selectivity of the method is also demonstrated by several competitive reactions. Ether formation, rearranged products, and polymerization have not been observed in the reactions. 相似文献
19.
I. L. Odinets E. A. Antonov P. V. Petrovsky Yu. I. Morozik Yu. A. Krivolapov B. I. Freger V. Ya. Starkov T. A. Mastryukova M. I. Kabachnik 《Russian Chemical Bulletin》1993,42(1):154-161
The reaction of 2-methyl-2,5-dioxo-1,2-oxaphospholane (1) with trimethylsilyl cyanide was found to give, depending on conditions, three organophosphorus compounds: trimethylsilyl methyl(2-cyanocarbonylethyl)phosphinate (2), trimethylsilyl methyl(3-trimethylsiloxy-3,3-dicyanopropyl)phosphinate (3) and trimethylsilyl methyl(3-trimethyl-siloxy-3-cyano-2-propenyl)phosphinate (4), On hydrolysis of3 under mild conditions, methyl(3-hydroxy-3,3 dicarboxypropyl)phosphinic acid (7) was obtained. The latter is readily decarboxylated on heating to give methyl(3-hydroxy-3-carboxy-propyl)phosphinic acid (8). The interaction of2 and4 with water or alcohols gives, correspondingly, methyl[2-carboxy(alkoxycarbonyl) ethyl]phosphinic acids (11–13). Methyl(2-oxamoyiethyl)phosphinic acid (14) was prepared by successive treatment of propenylphosphinate4 with HCl gas and water.Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 170–177, January, 1993. 相似文献
20.
Michel Sanchez Marie-Rose Mazieres Rainer Bartsch Robert Wolf Jean-Pierre Majoral 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-2):487-490
Abstract New phosphenium cations of general formula R2N-P+-X, with a variety of X group (-N=P+R2, -N=PR3, -C°N, -C=N=S, OR) are synthesized using trimethylsilyl derivatives as reagents. 相似文献