共查询到20条相似文献,搜索用时 93 毫秒
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以二苯硫醚为主要原料,以过氧化氢为氧化剂,在室温条件下氧化得到了二苯亚砜.然后,二苯亚砜与二苯硫醚在硫酸的作用下,进行缩合反应制备了双[(4-二苯硫)苯]硫醚-双-六氟磷酸盐,收率由文献报道的39%提高到75%;对其结构进行了UV、IR、H NMR和元素分析. 相似文献
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用双羟基偶氮(或氧化偶氮)苯化合物与对苯二甲酰氯缩聚反应合成了端羟基偶氮(或氧化偶氮)苯低聚物。将其与丁醇醚化氨基树脂进行电场极化交联反应合成交联型非线性光学聚合物。利用红外光谱和紫外可见吸收光谱分别对交联反应、电场极化取向稳定性进行了研究。 相似文献
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采用循环伏安法和恒电位电解法研究了离子液体EMimBF4中硝基苯在微铂电极上的选择性电还原特性. 研究结果表明, 硝基苯在铂电极上的电还原反应为双分子八电子三步骤电化学过程: 第一步反应为准可逆单电子转移步骤, 产生阴离子自由基; 第二步为二电子转移步骤, 并伴有随后的双分子不可逆自由基偶合反应和快速质子化及脱水反应, 主要产物为氧化偶氮苯; 第三步是二电子转移产生偶氮苯的过程. 通过控制电位, 可以选择性地合成氧化偶氮苯和偶氮苯; 在EMimBF4中, 硝基苯和水的浓度变化对电化学行为产生较大影响. 相似文献
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以4.4′-二羟基氧化偶氮苯和1,10-癸二醇作为含羟基单体,按不同的重量配比,合成了一系列含氧化偶氮苯液晶基元的共聚液晶高分子,改变液晶基元的含量,共聚物相变温度可以调节。 相似文献
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采用锌-柠檬酸氢二铵溶液还原体系,以偶氮苯为原料合成出氢化偶氮苯.合成反应的最佳反应条件:当偶氮苯用量是0.625 mmol时,偶氮苯与锌的物质的量之比为1:5,0.2 g/mL柠檬酸氢二铵溶液用量5.0 mL,室温,时间约3 min,平均收率90.63%. 相似文献
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以1,6-二溴己烷(A)和1,10-二溴癸烷(B)为共缩聚单体,按不同摩尔配比与4,4'-二羟基氧化偶氮苯经相转移催化共聚醚化反应,合成了一系列主链上含有氧化偶氮苯介晶基元的共聚醚,它们均有好的液晶性,其取向膜观察到条带织构,当A/B的摩尔比为1时液晶态范围最宽。 相似文献
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Abstract: Aryl or alkyl propargyl ethers have been isomerized efficiently with good to excellent yield into corresponding allenyl ethers in the presence of potassium tert-butoxide under the microwave irradiation. 相似文献
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A new zirconium-mediated, regio- and stereospecific SN2' substitution of allylic ethers with a nitrogen nucleophile has been developed. Cbz-protected amine products were isolated in high yield from reactions with a wide range of Z allylic ethers. A mechanism of the allylic substitution consistent with the results of the kinetics and kinetic isotope effect studies was proposed. 相似文献
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E. Troyano A. Olano M. Fernández-Díaz J. Sanz I. Martínez-Castro 《Chromatographia》1991,32(7-8):379-382
Summary Three silylation methods for the gas chromatographic analysis of ketohexoses have been compared for yield and tautomeric composition
of trimethylsilyl ethers. One of them has been applied to the analysis of milk monosaccharides and evaluated for precision
and accuracy. Of the different stationary phases employed, OV-215 and AT-1000 were the best suited to resolve the TMS ethers
of the studied sugars. 相似文献
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Dolly Kataki 《Tetrahedron letters》2009,50(17):1958-375
Iodine has been found to be an effective catalyst for one-pot synthesis of homoallyl benzyl ethers under mild reaction conditions. Various homoallyl benzyl ethers were synthesized in moderate to high yield by three-component condensation of aldehydes, benzyloxytrimethylsilane, and allyltrimethylsilane in presence of iodine (10 mol %) in dichloromethane at 0 °C. 相似文献
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Bradley D. Robertson 《Tetrahedron letters》2008,49(13):2088-2090
A new method for the regioselective preparation of silyl enol ethers from acyloin derivatives using silyllithium reagents has been developed. Both dimethylphenyl- and methyldiphenylsilyllithium were found to be effective, the latter providing greater stereocontrol. The reaction is believed to proceed via Brook rearrangement assisted by expulsion of the adjacent leaving group. A number of acyclic acyloin derivatives were reacted to form the corresponding silyl enol ethers in good to excellent yield. 相似文献
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Heather K. Baker 《Tetrahedron letters》2009,50(28):4012-2464
A new method for the stereoselective preparation of proximal β-hydroxy silyl enol ethers from α,β-epoxyketones using silyllithium reagents has been developed. The reaction is believed to proceed via Brook rearrangement assisted by opening of the adjacent epoxide. A number of α,β-epoxyketones were reacted with methyldiphenylsilyllithium to form the corresponding proximal β-hydroxy silyl enol ethers in good to excellent yield and excellent stereoselectivity. 相似文献
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A mild and efficient protocol for the deprotection of silyl ethers using KF in tetraethylene glycol is reported. A wide range of alcoholic silyl ethers can be selectively cleaved in high yield in the presence of certain acid- and base-labile functional groups. Moreover, the phenolic silyl ethers were cleaved exclusively, without affecting the alcoholic silyl ethers, at room temperature. 相似文献
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Hydrobromites of bridged bicyclic alcohols have been decomposed to yield tetrahydrofuran-type ethers as well as fragmentation products. The latter results from the cleavage of the carbon-carbon bond α, β to the hydroxyl group. In the case of 3-hydroxy-3-methyl bicyclo[3.2.1]octane, conjugated ketones and brominated olefins are formed, whereas tetrahydrofuran-type ethers are formed only under different experimental conditions different from those applicable to general cases. The reaction mechanisms have been established. The influence of the various reaction parameters has been studied in order to obtain selectively either tetrahydrofuran-type ethers or a mixture of conjugated ketones and brominated olefins. 相似文献
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The triphenylmethyl (trityl) moiety is frequently used for the protection of alcohols but the mass spectra of such trityl ethers have hitherto escaped scrutiny. It has now been found that triphenylmethyl derivatives of primary alcohols yield abundant molecular ions which permit the determination of the isotopic purity of the parent alcohol. Upon electron impact the triphenyl-methyl entity directs the fragmentation of trityl ethers as demonstrated by a detailed study of n-pentyl trityl ether and its deuterated analogs. Ions formed by migration of phenyl groups were observed in the mass spectra of the trityl ethers investigated as well as in the spectrum of triphenyl-methane itself. 相似文献