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71.
Masanori Watanabe 《Tetrahedron》2005,61(18):4409-4418
Magnesium alkylidene carbenoids were generated from 1-chlorovinyl p-tolyl sulfoxides with i-PrMgCl at −78 °C in THF or toluene via the sulfoxide-magnesium exchange reaction. Reaction of the generated magnesium alkylidene carbenoids with lithium acetylides or lithium thiolates gave conjugated enynes or vinyl sulfides, respectively, in moderate to good yields. The intermediate of this reaction was found to be the alkenyl anion and it could be trapped with some electrophiles to give tetra-substituted conjugated enynes and vinyl sulfides. 相似文献
72.
Summary A simple gas chromatographic method has been developed for analysis of hydrogen sulfide in hydrogen at the 0.5 to 100 ppm level. After enriching the traces of hydrogen sulfide by absorption in a gas loop packed with the chosen column support at 77 K it was determined by using a Chromosorb G column with silicone 550 and phthalic anhydride as liquid phases, hydrogen as carrier gas and a thermal conductivity detector. The detection limit was found to be about 0.5 ppm of hydrogen sulfide. 相似文献
73.
Mingzhong Cai Yizheng Huang Rongli Zhang 《Journal of organometallic chemistry》2004,689(15):2436-2440
A silica-supported poly-γ-diphenylarsinopropylsiloxane palladium(0) complex has been prepared from γ-chloropropyltriethoxysilane via immobilization on fumed silica, followed by reacting with potassium diphenylarsenide and palladium chloride, and then the reduction with hydrazine hydrate. The palladium(0) complex has been found to catalyze the allylation of aldehydes via the formation of π-allylpalladium complexes, using allylic chlorides as allylating agent and SnCl2 as reducing agent. This polymeric palladium complex can be recovered and reused. 相似文献
74.
The initial formation of organotin derivatives with Sn-S-N bonds in heterolytic reactions of hexamethylditin or trimethyltin sulfide withN-(chlorothio)phthalimide is suggested. Subsequent interaction of these compounds with sulfenyl chloride affordsN, N-thioorN, N-dithiobisphthalimide. Homolytic reaction of hexamethylditin withN, N-dithiobisphthalimide also occursvia an organotin intermediate, which, in the absence of a nucleophilic reagent, eliminates sulfur and converts intoN-trimethylstannylphthalimide.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2111–2114, December, 1993. 相似文献
75.
Bis- as well as tris-tetrahydropyranone ring systems were obtained via multiple tandem cyclization-1,3-dipolar cycloaddition reactions of α-diazo ketones with ketone as well as aldehyde functional groups in a chemoselective manner. 相似文献
76.
Yuandong Wu 《Journal of solid state chemistry》2005,178(5):1569-1574
The new ternary alkali tantalum polysulfide K2Ta2S10 has been synthesized by reacting TaS2 with an in situ formed melt of K2S3 and S at 773 K. The compound crystallizes with four formula units in the monoclinic space group P21/n (No. 14) with lattice parameters of . The structure contains two different zigzag chain anions [TaS5]−, running parallel to the crystallographic b-axis separated by potassium cations. The two crystallographically independent tantalum atoms are in a distorted bi-capped trigonal prismatic environment of eight sulfur atoms which was never observed before. The TaS8 polyhedra share three S atoms on each side to form the anionic chains. The compound was characterized with FIR and Raman spectroscopy. 相似文献
77.
Vnira R. Akhmetova Guzel R. Nadyrgulova Tat'yana V. Tyumkina Mikhail Yu. Antipin Usein M. Dzhemilev 《Tetrahedron》2007,63(47):11702-11709
Cyclocondensation of aliphatic diamines with CH2O and H2S (1:3:2 ratio, 0 °C) was carried out to give thiadiazabicyclanes and dithiadiazabicyclanes (1:6:4 ratio), which were previously difficult to synthesize. Symmetric α,ω-bis-1,3,5-dithiazinanes were synthesized at 80 °C by this reaction. The stereochemistry of thiadiazabicyclanes was assigned by 1H and 13C NMR spectroscopy and by theoretical DFT calculations, and of bis-dithiazinanes by X-ray diffraction study in the solid state. 相似文献
78.
The preparation of concentrated sols and transparent stiff gels of II-VI semiconductors nanocrystals is reported. A two-step process for the production of cadmium sulfide is reported. Sol stabilization and gelation control are achieved through successive passivation and depassivation of the surface of the nanocrystals which are complexed with thiols. The mechanisms driving the aggregation and the gelation are explained on the basis of NMR and SAXS experiments. Thin films as well as monoliths can be produced. The general principles of the method presented are not restricted to chalcogenide systems and thus enlarge the domain of application of the inorganic sol-gel process. 相似文献
79.
A method for the determination of sulfide based on its interference with the determination of Hg by cold vapor atomic absorption spectrometry is described. The decrease in mercury absorbance at 253.7nm is proportional to the concentration of sulfide over the range of 10–320ngmL–1. The limit of detection was found to be 7ngmL–1 and the relative standard deviation (R.S.D.) for the determination of different concentrations of sulfide was in the range of 1.8–2.2%. This method was applied to the determination of sulfide in whole human blood after gas-phase separation. 相似文献
80.
Hidetake Sakuraba Hiroshi Maekawa 《Journal of inclusion phenomena and macrocyclic chemistry》2006,54(1-2):41-45
The two modified β-cyclodextrin (β-CD) derivatives having catechol-type ligand (2,3- and 3,4-dihydroxy groups on the benzoate
ring) were synthesized. The chiral catalytic activity of their MoV and CuII complexes was examined in the asymmetric oxidation of aromatic sulfides using hydrogen peroxide in water (pH 6.0). The oxidation
with the MoV complexes of two β-CD derivatives were more accelerated than that with the CuII complexes. The sign of the optical rotation of the sulfoxides obtained in the above two cases showed the opposite configuration
in the oxidation of the same sulfide. The difference of the enantioselectivity appeared also between the two complexes of
the 2,3- and 3,4-dihydroxybenzoate derivatives with the same metal ion. While the use of the MoV complexes with the catechol derivatives yielded the sulfoxides with 35–65% ee, the use of the CuII complexes gave the products with the␣opposite configuration at 26–52% ee. The chiral induction in the oxidation, observed
conversely between the␣catalysts, was reflected on the chiral conformation of the respective metal catalysts, showed in Induced
Circular Dichroism (ICD) spectra. The highest optical yield, 65%, was observed in the oxidation of butyl phenyl sulfide using
the catalytic amount (0.1 equiv) of the MoV complex with mono-6-O-(3,4-dihydroxybenzoyl)-β-CD. The reaction gave predominantly the (S)-sulfoxide in 95% chemical yield. 相似文献