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371.
3‐Methyl‐2‐benzofurancarboxylic acid hydrazide ( 2 ) reacts with carbon disulfide and pota‐ ssium hydroxide to give the corresponding potassium carbodithioate salt 3 . Treatment of the latter salt with hydrochloric acid, hydrazine hydrate, and with phen‐ acyl bromide afforded the corresponding 1,3,4‐oxadia‐ zole‐5‐thione 4 , 4‐amino‐1,2,4‐triazole‐5‐thione 5 , and thiazolidine‐2‐thione 9 derivatives, respectively. The reaction of either 1,3,4‐oxadiazole‐5‐thione 4 or 4‐amino‐1,2,4‐triazole‐5‐thione 5 with phenacyl bromide resulted in the formation of 1,2,4‐triazolo[3, 4‐b]‐1,3,4‐thiadiazine derivative 8 . Treatment of compounds 3 or 4 with hydrazonoyl halides 10a–d furn‐ ished the same 1,3,4‐thiadiazol‐2‐ylidene derivatives 11a–d . The 7‐arylhydrazono‐1,2,4‐triazolo[3,4‐ b ]‐1, 3,4‐thiadiazine derivatives 12a–d were obtained either by treatment of 4‐amino‐1,2,4‐triazole‐5‐thione 5 with hydrazonoyl halides 10a–d or by coupling of the 1,2,4‐triazolo[3,4‐b]‐1,3,4‐thiadiazine derivative 8 with diazonium salts. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:621–627, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20162 相似文献
372.
Thierry Hamaide Magdalena Pantiru Hatem Fessi Paul Boullanger 《Macromolecular rapid communications》2001,22(9):659-663
Functionalised polycaprolactones have been obtained by anionic coordinated ring‐opening polymerisation with Al(OiPr)3 as the initiator in the presence of monosaccharides as transfer agents. 1H and 13C NMR spectroscopy, as well as MALDI‐TOF mass spectrometry clearly show the functionalisation of the polycaprolactone chains. Protected monosaccharides bearing primary hydroxyl groups are suited best to get well‐controlled polymer chains. Polycaprolactones functionalised with galactopyranose end groups have been used for the preparation of nanoparticles according to the emulsification‐diffusion procedure. Nanospheres and nanocapsules with diameters around 0.50 μm could be obtained. 相似文献
373.
Georgia Papavasiliou nan Birol Fouad Teymour 《Macromolecular theory and simulations》2002,11(5):533-548
Mathematical Modeling of non‐linear polymerization systems subject to gel formation is a challenging endeavor. At the gel point, the second and higher molecular weight moments diverge to infinity making it impossible to obtain the molecular weight distribution (MWD). The numerical fractionation (NF) technique utilizes a refinement of the method of moments to model non‐linear polymerization systems that form gel. Since the method of moments yields results in terms of average quantities, some information is lost when reconstructing the MWD using NF. As a consequence, a broad shoulder appears at the high chain length end of the MWD tail. This study demonstrates that the validity of the gamma distribution deteriorates for the broader branched polymer generations and evaluates the performance of various alternative model distributions. Proper selection of the model distribution enhances the NF‐reconstructed MWD. 相似文献
374.
Hatem A. Abuelizz Ahmed H. Bakheit Mohamed Marzouk Mohamed M. Abdellatif Rashad Al-Salahi 《Molecules (Basel, Switzerland)》2022,27(11)
The cyclic anhydrides are broadly employed in several fields, such as the chemical, plastic, agrochemical, and pharmaceutical industries. This study describes the chemical reactivity of 4,5-dichlorophthalic anhydride towards several nucleophiles, including thiosemicarbazide and different amines, to produce the carboxylic acid derivatives resulting from anhydride’s opening, namely, phthalimide and dicarboxylic acid (1–12) products. Their chemical structures are confirmed by NMR, IR and MS spectra analyses. Density–functional theory (DFT) studies are performed using (DFT/B3LYP) with the 6-311G(d, p) basis sets to recognize different chemical and physical features of the target compounds. 相似文献
375.
With a view to creating a specific unique chip, its wearable, flexible and conductor.utilizing conventional physical methods like grafting and assembling metals (silver, copper, and gallium indium alloy) on graphene as composite, then immersed inside PDMS matrix. However, there is an incompatibility between liquid gallium and graphene sheet. So we used the abridge of metallic nanoparticles as silver and copper as a boundary barrier to its different charges to maximize interfacial surface interaction in between amorphous carbon and liquid gallium. to evaluate the chip conduct during the fabrication process we utilize various characterization such as electrochemical EIS and CVT to justify conductivity besides electrochemical reaction and oxidation and reduction, addition to measure the dielectric constant (?) of a composite at a different range of frequencies which is equal to 3.73 compared to PDMS 2.69.moreover its thermal stability (DSC) of prepared composite and tensile stress as an inductor for enforcement and enhancement physical properties, as well as, surface Morphology techniques characterize using TEM IR, and UV absorption. 相似文献
376.
Zedek Rezika Djedjiga Hatem Megherbi Mohamed Belkaid Mohammed Said Ntsoenzok Esidor 《Journal of Sol-Gel Science and Technology》2021,100(1):44-54
Journal of Sol-Gel Science and Technology - In this research work, undoped and slight Fe-doped-TiO2 nanoparticles (Fe–TiO2 NPs) were prepared using simple chemical sol–gel method and... 相似文献
377.
378.
Bakr F. Abdel-Wahab Hatem A. Abdel-Aziz Essam M. Ahmed 《Monatshefte für Chemie / Chemical Monthly》2009,140(6):601-605
Abstract Potassium hydrazinecarbodithioate were prepared by treatment of acid hydrazides with carbon disulfide in the presence of potassium
hydroxide. Reaction of this potassium salt with hydrazine hydrate, phenacyl bromide, or hydrazonoyl chlorides afforded 1,2,4-triazole,
1,3-thiazole, and 1,3,4-thiadiazoles. Reaction of 1,2,4-triazole with phenacyl bromide or hydrazonoyl chlorides afforded the
corresponding 1,2,4-triazolo[3,4-b][1, 3, 4]-thiadiazines. All these new compounds were screened for antibacterial and antifungal activity. Some had promising
activity.
Graphical abstract
相似文献
379.
380.
Djaafar Zouache Abdelouahab Moussaoui Fouad Ben Abdelaziz 《European Journal of Operational Research》2018,264(1):74-88
We propose a novel cooperative swarm intelligence algorithm to solve multi-objective discrete optimization problems (MODP). Our algorithm combines a firefly algorithm (FA) and a particle swarm optimization (PSO). Basically, we address three main points: the effect of FA and PSO cooperation on the exploration of the search space, the discretization of the two algorithms using a transfer function, and finally, the use of the epsilon dominance relation to manage the size of the external archive and to guarantee the convergence and the diversity of Pareto optimal solutions.We compared the results of our algorithm with the results of five well-known meta-heuristics on nine multi-objective knapsack problem benchmarks. The experiments show clearly the ability of our algorithm to provide a better spread of solutions with a better convergence behavior. 相似文献