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91.
Néstor M. Carballeira David Sanabria Norma L. Ayala Clarisa Cruz 《Tetrahedron letters》2004,45(19):3761-3763
A stereoselective synthesis for the (5Z,9Z)-14-methyl-5,9-pentadecadienoic acid and the monounsaturated analog (Z)-14-methyl-9-pentadecenoic acid was accomplished in six to seven steps where double alkyne coupling was the key step. This synthesis will facilitate the study of the topoisomerase I inhibitory profile of this important class of fatty acids. 相似文献
92.
Uwe Rosenthal Andreas Ohff Wolfgang Baumann Annegret Tillack Helmar Grls Vladimir V. Burlakov Vladimir. B. Shur 《无机化学与普通化学杂志》1995,621(1):77-83
Structure, Properties, and NMR Spectroscopical Characterization of Cp2Zr(pyridine)(Me3SiC?CSiMe3) Displacement of the THF ligand in Cp2Zr(THF)(Me3SiC?CSiMe3) ( 1 ) with pyridine yields Cp2Zr(η1-NC5H5)(Me3SiC?CSiMe3) (3). Unlike 1 , the complex 3 is stable in hydrocarbon solvents. According to the temperature dependent 1H and 13C NMR spectra, the structure of complex 3 in solution is dynamic due to a rotation of the alkyne ligand. In addition, when 3 is dissolved in pyridine an easy exchange between coordinated and free molecules of pyridine takes place. In the solid state complex 3 displays a tetrahedral coordination sphere at the zirconium center composed of Cp ligands, alkyne and pyridine as shown by an X-ray structure analysis. The complex 3 reacts readily with water and carbon dioxide giving the same products as in the case of 1 . 相似文献
93.
The reaction of 2,5-didodecyl-1,4-dipropynylbenzene with different molybdenum sources (Mo(CO)6, norbornadiene-Mo(CO)4, cyclooctadiene-Mo(CO)4, cycloheptatriene-Mo(CO)3, (PhCCPh)3Mo(CO), (acac)2MoO2/AlEt3) was investigated in the presence of 4-chlorophenol or 2-fluorophenol. Upon heating to 105-130 °C, the formation of didodecyl-PPE resulted. The degree of polymerization of the PPE is dependent on the used phenol and to the utilized molybdenum precursor. The most active catalyst forms from (acac)2MoO2, AlEt3 and 2-fluorophenol. This catalyst combination gives high molecular weight PPEs after 6 h at 105 °C. 相似文献
94.
A practical approach has been developed for the catalytic synthesis of short oligomers, dimers and/or trimers of terminal alkynes. The method allows control of the extent and, in some cases, the regiospecificity in the catalyzed oligomerization of terminal alkynes promoted by bis(pentamethylcyclopentadienyl)uranium dimethyl complex (Cp*2U(CH3)2, Cp*=C5Me5). The metallocene precursor is known to promote the simultaneous production of a large number of differently sized oligomers in the presence of terminal alkynes. However, the addition of a specific secondary silane ensures the selective synthesis of short oligomers. 相似文献
95.
Evelia RasolofonjatovoBret Tréguier Olivier ProvotAbdallah Hamze Estelle MorvanJean-Daniel Brion Mouad Alami 《Tetrahedron letters》2011,52(9):1036-1040
A convenient and efficient procedure for the synthesis of 4-arylchromenes, thiochromenes, and related heterocycles via a four step-sequence has been developed. The first three steps, which involve hydration of alkynes, hydrazones formation, and their Pd-coupling with ortho substituted aryl halides, furnished stereoselectively Z-trisubstituted olefins without any purification of the intermediates generated in each stage. These latter proved to be suitable precursors, in the last step, for the synthesis of the desired heterocycles of biological interest. 相似文献
96.
We describe in this work an alkyne-hydrosilylation approach to synthesize a series of novel polysiloxane sidechain LCPs attaching end-on or side-on mesogenic side groups. Their properties are characterized by NMR, FTIR, gel permeation chromatography, thermogravimetric analysis, differential scanning calorimetry, polarized optical microscopy and small-angle X-ray scattering. These obtained alkenylsilane linked novel LCPs exhibit higher glass transition temperatures and clearing points, and especially display the tendency of forming smectic phases, in strong contrast with the nematic phases of their comparative conventional alkylsilane linked analogues, which manifests more rigid features of the alkenylsilane linkages and their significant influence on the mesomorphic properties. 相似文献
97.
Balakrishna Dulla Sunder Kumar Kolli Upendar Reddy Chamakura Giridhar Singh Deora R. Ramesh Raju 《合成通讯》2014,44(10):1466-1474
A simple and inexpensive synthesis of novel 2-(3-oxo-3-arylpropyl)-2,3-dihydro-1H-inden-1-one derivatives has been achieved via Pd/C-mediated arylation followed by I2-mediated regioselective hydration of 2-(prop-2-ynyl)-2,3-dihydro-1H-inden-1-ones. A wide variety of 3-aryl substituted 2-propynyl indanone derivatives were conveniently prepared by using 10% Pd/C-PPh3-CuI as a catalyst system, some of which were used to prepare the corresponding ketones via alkyne hydration in the presence of catalytic I2. In an in vitro study a representative compound showed inhibition of PDE4B (phosphodiesterase type 4B) and binding with this protein in silico 相似文献
98.
Balakrishna Dulla E. Sailaja Upendar Reddy CH Madhu Aeluri Arunasree M. Kalle S. Bhavani D. Rambabu M.V. Basaveswara Rao Manojit Pal 《Tetrahedron letters》2014
Indole based novel small molecules were designed as potential anticancer agents. Multi step synthesis of these compounds was carried out by using Pd/C–Cu mediated coupling–cyclization strategy as a key step. The single crystal X-ray diffraction study was used to confirm the molecular structure of a representative compound unambiguously. Many of these compounds were evaluated for their anti-proliferative properties in vitro against six cancer cell lines as well as noncancerous cells. All these compounds showed selective growth inhibition of cancer cells and several of them were found to be promising with IC50 values in the range of 0.1–1.2 μM, comparable to the known anticancer drug doxorubicin. 相似文献
99.
A novel and efficient synthesis of N-substituted pyrrolo-pyrazinone derivatives has been developed. A trichloroacetyl group connected to the pyrrole ring was converted into the desired carboxamide derivatives. Promoted by NaH, the pyrrole carboxamide derivatives underwent a tandem reaction with propargyl bromide to afford pyrrolo-pyrazinones with high efficiency under very mild conditions. The mechanism for the formation of the products is discussed and supported by DFT calculations. 相似文献
100.
《Journal of Saudi Chemical Society》2014,18(2):115-119
Silica supported polyphosphoric acid (SiO2-PPA) as an efficient heterogeneous catalyst was found to be effective for the one-pot three-component condensation reaction of phenyl acetylene/1-hexyne, aromatic aldehyde and benzamide/acetamide to produce a series of N,N′-alkylidene bisamides. The desired products were obtained in good to high yields. The assistance of alkynes has been confirmed by using thin layer chromatographic (TLC) studies. All the reactions were done at 100 °C using 0.025 g of catalyst. The developed method is valid for either substituted aldehyde, thus it constitutes a general synthetic method for these kinds of compounds. In all the cases aromatic aldehydes containing electron-withdrawing groups gave shorter time than that with electron-donating groups. Additionally, the reaction of butyraldehyde with benzamide failed to have any product in the presence of phenyl acetylene but with 1-hexyne the product was formed in moderate yield. 相似文献