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141.
T. I. Yaroshenko V. N. Elokhina A. S. Nakhmanovich L. I. Larina T. N. Komarova S. V. Amosova 《Russian Journal of General Chemistry》2009,79(6):1197-1200
Propargyl bromide with quinoxaline-2,3-dithiol in DMSO in the presence of K2CO3 affords 2,3-bis-(2-propynylsulfanyl)quinoxaline in good yield whereas in absolute methanol in the presence of sodium methoxide at 20°C a 1:2 mixture of 2,3-bis(2-propynylsulfanyl)quinoxaline and 3-(2-propynylsulfanyl)-2(1H)-quinoxalinethione is formed. Individual 3-(2-propynylsulfanyl)-2(1H)-quinoxalinethione was obtained by crystallization of this mixture from ether. The reaction of 1,3-dibromopropyne with quinoxaline-2,3-dithiol in ethanol in the presence of NaOH at heating results in 2-bromomethylidene-1,4-(3H)-dithiino[2,3-b]quinoxaline in 77% yield. Performing this reaction in methanol in the presence of sodium methoxide during long heating (16 h) led to 2,3-bis[(3-bromo-2-propynyl)sulfanyl]quinoxaline in 72% yield. 相似文献
142.
E. I. Biryukova S. V. Amosova S. A. Zhivet’eva E. D. Bedoshvili Y. V. Likhoshway 《Polymer Science Series B》2009,51(3-4):117-123
The kinetics of the free-radical copolymerization of styrene with divinyl sulfide in the presence of N,N′-bis(vinyloxyethyl)thiuram disulfide as an iniferter has been studied. The rate of polymerization is shown to decrease with increasing iniferter concentration. The structure of the copolymers isolated in the course of copolymerization has been investigated by electron microscopy and compared with that of the copolymers synthesized using AIBN as an initiator. Evolution in the morphology of the polymer phase during the process, which consists in self-organization of the secondary supramolecular structure into spheroids with diameters of 0.1–10 μm, has been revealed. The stages of the formation of polymer particles of various structures are described by the scheme of morphogenesis. 相似文献
143.
144.
Jan ?ermák Alena Krupková Milan Zamrzla Pavel Vojtíšek 《Journal of organometallic chemistry》2010,695(3):375-381
Tetramethyl(perfluoroalkyl)cyclopentadienyl rhodium(I) complexes with ethylene or diene (norbornadiene, cycloocta-1,5-diene, 2,3-dimethylbuta-1,3-diene, cyclohexa-1,3-diene) ligands were obtained by reduction of tetramethyl(perfluoroalkyl)rhodium(III) dichloro dimers by zinc in THF or by propan-2-ol/sodium carbonate in the presence of the ligands. Reduction in the presence of cycloocta-1,3-diene gave a different product, an η3-cyclooctenyl complex, which was not reduced further. During the reduction in the presence of ethylene, a new tetramethyl(perfluoroalkyl)-η4-cyclopentadiene complex was observed by NMR. This compound, formed by hydrogen transfer from the metal to the ligand, is probably in an equilibrium with the parent hydridocyclopentadienyl complex. Crystal and molecular structure of dicarbonyltetramethyl(perfluorohexyl)cyclopentadienylrhodium(I) complex was determined by X-ray diffraction. The structure shows a moderate ring slippage of the rhodium atom which was not observed in the only other known structure of a complex with the same ligand, the rhodium(III) dichloro dimer. 相似文献
145.
den Hartog T Rudolph A Maciá B Minnaard AJ Feringa BL 《Journal of the American Chemical Society》2010,132(41):14349-14351
Cu-TolBINAP-catalyzed conjugate addition of Grignard reagents to 4-chloro-α,β-unsaturated esters, thioesters, and ketones leads to 4-chloro-3-alkyl-substituted thioesters and ketones in up to 84% yield and up to 96% ee upon protonation of the corresponding enolates at low temperature. Tandem conjugate addition-enolate trapping, however, yields trans-1-alkyl-2-substituted cyclopropanes in up to 92% yield and up to 98% ee. The versatility of this reaction is illustrated by the formation of key intermediates for the formal syntheses of cascarillic acid and grenadamide. 相似文献
146.
A. V. Martynov N. A. Makhaeva L. I. Larina S. V. Amosova 《Russian Journal of Organic Chemistry》2010,46(11):1675-1677
The electrophilic additiob of sulfur dichloride and selenium tetrachloride to diallyldimethylsilane proceeds strictly according
Markownikoff rule and results in the formation of previously unknown saturated siliconcontaining heterocycles, 5,5-dimethyl-3,7-dichloro-1,5-thiasilacyclooctane
and 5,5-dimethyl-1,1,3,7-tetrachloro-1,5-selena(IV)silacyclooctane. The structure of heterocycles obtained was confi rmed
by 1H, 13C NMR spectra, in the case of selenium-containing heterocycle, by 77Se NMR spectrum, among them the 2D HMBC spectrum. 相似文献
147.
Inna P. Tsypysheva Alexander N. Lobov Alena V. Kovalskaya Polina R. Petrova Sergey P. Ivanov Shamil A. Rameev 《Natural product research》2015,29(2):141-148
The first example of aza-Michael reaction of 12-N-carboxamide of quinolizidine alkaloid (–)-cytisine with α,β-unsaturated ketones, dimethyl acetylenedicarboxylate and β-nitrostyrene under high pressure condition has been described. It has been shown that the [4+2]-cycloaddition takes place in the case with N-phenylmaleimide. 相似文献
148.
149.
The spectrochemical behavior of nonvolatile tungsten and boron was tested by adding different buffers and using 12 A ac arc excitation. The oxidization and sulfidization processes were found to be most effective for facilitating the volatilization. The optimal admixture was the copper oxide buffer for both the detection limit and the precision of the method. The reference values of the background or a palladium line blackening were used. 相似文献
150.
The addition of diorganyl disulfides and dimethyl diselenide to cyclohexene in the presence of tin(IV) chloride proceeded stereoselectively affording trans-adducts of 1:1 composition. No reaction occurs in the absence of tin(IV) chloride. 相似文献