呋喃类化合物在离子液体和硅胶负载离子液体中的Diels-Alder反应

以1-丁基-3-甲基咪唑盐作为离子液体阳离子,与3种不同阴离子BF4、PF6、Tf2N组成性质不同的3种离子液体,催化呋喃类和丁炔二羧酸酯之间发生Diels-Alder反应,合成了一系列化合物,研究了离子液体的催化效果.研究结果表明,呋喃类化合物的极性越低, Diels-Alder反应的活性越高.在含硫的呋喃类化合物的反应中,当以[Bmim]PF6作离子液体时,Diels-Alder反应产率可达53%.当[Bmim]PF6离子液体被吸附在硅胶表面上时,Diels-Alder的反应产率有所提高.     

超声辐射下几种腙类化合物的合成研究

以乙酰丙酮为起始原料,经三步反应制得了w-溴代-1-苯基-5-甲基吡唑-4-乙酮(5).中间体5在超声波辐射下与芳基乙酮缩氨基硫脲类化合物(1a-1g)反应生成了新型的N-(1-芳基乙酮)-N1-[(1-苯基-5-甲基吡唑-4-基)噻唑-2-基]腙(6a-6g).以1H NMR,IR,MS和元素分析对产物进行了确证及表...     

Cetyltrimethylammonium chloride (CTAC) catalyzed one-pot synthesis of novel coumarin-4H-pyran conjugates in aqueous media

Novel fluorescent coumarin-4H-pyran conjugates were achieved by three-component reactions of various synthetic β-ketoesters with aldehydes and malononitrile in aqueous media.Besides mild reaction conditions,operational simplicity,absence of tedious separation procedures,using of inexpensive and nontoxic commercially available cationic surfactant cetyltrimethylammonium chloride(CTAC) as a catalyst are the prominent advantage of this method.     

4-Dimethylaminopyridine-catalyzed multi-component one-pot reactions for the convenient synthesis of spiro[indoline-3,4′-pyrano[2,3-c]pyrazole] derivatives

An efficient and clean reaction process was developed for the convenient and cheap synthesis of spirooxindole derivatives. One-pot reactions of isatins, malononitrile (or ethyl cyanoacetate), hydrazine hydrate (or phenylhydrazine), and 1,3-dicarbonyl compounds were compared with one-pot reactions of isatins, malononitrile (or ethyl cyanoacetate), and 5-pyrazolone derivatives. Both sets of reaction were conducted in EtOH in the presence of 4-DMAP catalyst. A series of spiro[indoline-3,4′-pyrano[2,3-c]pyrazole] derivatives were quickly obtained in excellent yields by using the four-component one-pot reaction method.     

Coherent control of laser pulse temporal duration: An experimental proposal

We present a study of temporal compression resulting from the coherent control peculiarities of electromagnetically induced transparency propagation dynamics. We discuss the crucial conditions required to accomplish temporal compression in an experiment with a sample of hot atoms.     

Codes that attain minimum distance in every possible direction

The following problem motivated by investigation of databases is studied. Let be a q-ary code of length n with the properties that has minimum distance at least n − k + 1, and for any set of k − 1 coordinates there exist two codewords that agree exactly there. Let f(q, k)be the maximum n for which such a code exists. f(q, k)is bounded by linear functions of k and q, and the exact values for special k and qare determined.      

3-(2-萘基)-1-苯基-吡唑-4-甲醛腙衍生物的简便合成与表征

为寻找具有生物活性的先导化合物,以3-(2-萘基)-1-苯基-吡唑-4-甲醛为起始原料,在超声波辐射下经串联反应和"一锅法合成"两种途径制备了一系列新型的1-(3-β-萘基-1-苯基吡唑-4-亚甲基)-2-(4-芳基噻唑-2-基)-腙及其衍生物.与加热实验相比,在超声波辐射下可得到较好的产率.利用1H NMR,MS,IR谱和元素分析对产物进行了结构表征.初步的生物活性测试结果表明,化合物4b和4d对H2O2诱导的PC12细胞损伤具有明显的保护作用.     

Zur Abschätzung der Fourierkoeffizienten ganzer Modulformen

Ohne ZusammenfassungAls Inaugural-Dissertation von der Philosophischen Fakultät der Universität Leipzig zugelassen.