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221.
AbstractThe high functionality compound namely 2-cyano-3-(1,3-diphenyl-1H-pyrazol-4-yl)acryloyl chloride (1) was utilized as a building block synthon via reactions with some nitrogen and sulfur nucleophilic reagents. The present work was planned to study the effect of 2-cyano group on the reactivity and stability of C2–C3 double bond toward different strong-to-weak nucleophiles, in addition to its facility of nucleophilic addition at C2–C3 double bond to construct new heterocyclic derivatives. The proclivity toward some mono-, 1,2-, 1,3-, 1,4-, and 1,5-binucleophiles was investigated. The reaction with 2-cyanoacetohydrazide was mainly dependent on the reaction conditions. Some new heterocycles integrated with pyrazole scaffold were successfully synthesized, such as benzoxazinone, indoline, isoindoline, pyrazolone, chromene, and pyrimidopyrimidine derivatives. Some of the newly synthesized compounds were screened for their antioxidant activity using ABTS method, and the results revealed that some compounds exhibited promising inhibitory antioxidant activity. 相似文献
222.
Zaghal Mukarram H. Abu-Obeid Mona A. Atfah Mohammad A. El-Qisairi Arab K. Qaseer Hanan A. Ali Basem F. 《Transition Metal Chemistry》2001,26(4-5):517-522
3,6-Bis(2-pyridyl)pyridazine derivatives (n-dppn) react with hydrated rhodium(III) chloride and bromide (prepared in situ) to give cis-[Rh(n-dppn)2Cl2]PF6·xH2O (n = 5, 6, 7, 8) and cis-[Rh(n-dppn)2Br2]Br·xH2O (n = 5, 7) complexes, which have been characterized by elemental analyses, conductivity measurements, i.r., electronic and 1H- and 13C-n.m.r. spectra. 相似文献
223.
Synthesis and properties of the elusive ruthenium(II) complexes of 4'-cyano-2,2':6',2' '-terpyridine
The heteroleptic and homoleptic ruthenium(II) complexes of 4'-cyano-2,2':6',2' '-terpyridine are synthesized by palladium catalyzed cyanation of the corresponding Ru(II) complexes of 4'-chloro-2,2':6',2' '-terpyridine. The introduction of the strongly electron-withdrawing cyano group into the Ru(tpy)(2)(2+) moiety dramatically changes its photophysical and redox properties as well as prolongs its room temperature excited-state lifetime. 相似文献
224.
225.
Thierry Thami Gihane Nasr Hanan Bestal Arie Van Der Lee Bruno Bresson 《Journal of polymer science. Part A, Polymer chemistry》2008,46(11):3546-3562
Thin films of crosslinked polymethylhydrosiloxane (PMHS) have been grafted on silica using the sol–gel process allowing further functionalization by effective quantitative hydrosilylation of SiH groups by olefins within the network. Postfunctionalization gives the polysiloxane network with n‐alkyl side chains. The PMHS coating was prepared by room temperature polycondensation of a mixture of methyldiethoxysilane HSiMe(OEt)2 monomer and triethoxysilane HSi(OEt)3 (TH) as crosslinker. The surface‐attached films are chemically stable and covalently bonded to the silica surface. Subsequently, films were functionalized without delamination. We showed by FTIR spectroscopy how the crosslinking ratio and the molecular size of the alkenes precursors influence the extent of the hydrosilylation reaction of SiH groups in the PMHS network. We have determined that quasi‐full olefin addition catalyzed by a platinum complex occurred within soft networks of less than 5% TH with 1‐alkenes CH2?CH(CH2)n‐2CH3 of various alkyl chain lengths (n = 5, 11, 17). Powders of PMHS gel were also modified with 1‐alkenes by hydrosilylation. The SiH groups within the soft gel (5% crosslinked) were fully functionalized as shown by 29Si and 1H solid‐state NMR. The structure of functionalized polysiloxane with n‐octadecyl and n‐dodecyl side chains was studied by FTIR, wide angle X‐ray diffraction, and DSC showing crystallization of the long n‐alkyl chains in the network. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3546–3562, 2008 相似文献
226.
Hanan Luss 《The Journal of the Operational Research Society》1980,31(3):239-245
This note describes a model for advanced reservations extended to systems which can serve many customers at the same time. The new model has been developed for a communication network which provides intercity visual conferencing services via a satellite capable of accommodating many conferences simultaneously. Each customer calls in advance to reserve time on a future date. A scheduler either satisfies the request, or offers available alternatives which may or may not be acceptable to the customer. The model is used to examine different measures of quality-of-service and system utilization. 相似文献
227.
Inspection policy models deal with stochastically failing systems, in which failure is detected by inspection only. Previous authors assume that the time required for checking is zero, while the current study deals with preparedness models when duration of checking is non-negligible. Costs are introduced for checking, unknown lost time and repairing (or replacing) the failed system. Furthermore, uncertainty probabilities associated with inspections are introduced. Optimal checking policies are calculated for three different objective functions: expected loss per cycle, per time unit and per unit of good time. The models are solved by differentiation and by dynamic programming. Numerical results indicate that the optimal policy for IFR distributions is characterized by decreasing checking time intervals, with a marked difference only between the first and second intervals. 相似文献
228.
AbstractIn this study, a new series of quinazoline and their annulated derivatives have been synthesized. A number of quiazolinone derivatives substituted at position-3 were prepared from 3, 1-benzoxazinone by the treatment of 3,1-benzoxazinone with different nitrogen nucleophiles such as, hydrazine hydrate, phenylhydrazine, ethanolamine, and cyano acetohydrazide afforded the quinazolinone derivatives 7–11. The reaction of hydrazide derivative 5 with aromatic aldehydes gave the Schiff’s bases derivative 16a–c. Some of the synthesized compounds were tested against the breast cancer cell line (MCF-7). The structures of all the newly synthesized compounds were established based on IR, 1H, 13C NMR, mass spectral data, and elemental analyses. 相似文献
229.
The reaction of the sterically crowded dinuclear gold(I) amidinate complex Au2(2,6-Me2Ph-form)2, 1, with the less bulky bidentate nitrogen ligands results in the formation of tetranuclear gold(I) complexes. When the less bulky amidinate, K(4-MePh-form), A, was reacted with 1 in a 1:1 stoichiometric ratio, crystals containing equal amounts of the tetranuclear and dinuclear gold(I) aryl formamidinates, Au4(4-MePh-form)4 and Au2(2,6-Me2Ph-form)2, where 2,6-Me2Ph-form = B, were found in the same unit cell, 2 x 2THF: space group P, a = 10.794(11) A, b = 14.392(15) A, c = 25.75(3) A, alpha = 82.564(17) degrees, beta = 85.443(18) degrees, gamma = 82.614(19) degrees. The reaction of K(4-MePh-form), A, and 1 in a 1:2 ratio (excess) produced the tetranuclear complex only, 3. The potassium salt of the exchanged bulky ligand, K(2,6-Me2Ph-form), formed as a byproduct. The reaction of the dinuclear gold(I) complex Au2(2,6-Me2Ph-form)2 with the 3,5-diphenylpyrazolate salt, K(3,5-Ph2pz), resulted in the formation of two tetranuclear mixed-ligand complexes, Au4(3,5-Ph2pz)2(2,6-Me2Ph-form)2 x 2THF, 4 x 2THF (space group P21/c, a = 11.5747(19) A, b = 25.497(4) A, c = 21.221(3) A, beta = 96.979(3) degrees) and Au4(3,5-Ph2pz)3(2,6-Me2Ph-form) x THF, 5 x THF (space group P21/c, a = 23.058(5) A, b = 14.314(3) A, c = 18.528(4) A, beta = 90.94(3) degrees. The block crystals from the tetranuclear complex, 4 x 2THF, contain mixed ligands with each pyrazolate ring facing an amidinate ring. The tetranuclear mixed ligand complex, 5 x THF, was isolated as needles with ligands alternating above and below the Au4 plane. The two tetranuclear mixed-ligand complexes emit at 490 and 530 nm, respectively, under UV excitation. 相似文献
230.