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标题反应于室温在F_(113)(CClF_2CCl_2F)溶液中瞬间完成,产物经分析确定,该反应由硝基烷烃阴离子(R~1R~2CNO_2)向全氟酰基过氧化物(R_FCO_2)_2的单电子转移的决速步骤,生成全氟羧酸盐,全氟酰氧基自由基之脱羧偶合产物R_F—R_F(1)及硝基烷烃自由基偶合产物DN(2);但主要的产物是自由基笼内结合所生成的中间体立即发生1,2-消除得到的醛或酮.本文提供了一个由硝基烷烃合成相应醛和酮的新反应。 相似文献
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通过EPR技术观察到一系列典型的烷基或甲氧基取代的苯基烷基酮ArCOR(Ar=2,5-二甲基苯基(1);2,5-二甲氧基苯基(2);4-叔丁基-2,5-二甲氧基苯基(3))与t-BuMgCl反应中形成的自由基阴离子中间体[ArC(R)OMgCl]。产物分析表明,反应主要生成还原产物[ArCH(R)OH]和1,2-加成产物[ArC(R)(t-Bu)OH]。降低溶剂极性及反应温度都有利于还原产物的生成。对上述反应的可能历程作了简单讨论。 相似文献
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测定了过氧化月桂酰(1),过氧化辛酰(2),过氧化己酰(3)和过氧化3,5,5-三甲基己酰(4)在热分解过程中生成的羧基转化产物[RC(O)OC(O)OR,R=正十一烷基(5),正庚基(6),正戊基(7),2,4,4-三甲基戊基(8)]的含。在同样条件小,4生成的羧基转化产物比1,2和3的多。羧基转化反应受溶剂极性和粘度的影响,但温度的影响较小。转化产物的分解受体系中相应脂肪酸的催化。直接光照可生成少量转化产物,二苯酮光敏化不产生羧基转化产物,文中对反应机理进行了讨论。 相似文献
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测定了过氧化月桂酰(1),过氧化辛酰(2),过氧化己酰(3)和过氧化3,5,5-三甲基己酰(4)在热分解过程中生成的羧基转化产物[RC(O)OC(O)OR,R=正十一烷基(5),正庚基(6),正戊基(7),2,4,4-三甲基戊基(8)]的含量,在同样条件下,4生成的羧基转化产物比1,2和3的多,羧基转化反应受溶剂极性和粘度的影响,但温度的影响较小,转化产物的分解受体系中相应脂肪酸的催化,直接光照可生成少量转化产物,二苯酮光敏化不产生羧基转化产物,文中对反应机理进行了讨论。 相似文献
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由全氟(2-丙氧基丙酰)过氧化物[n-C3F7OCF(CF3)COO]2与亚硝酸钠制得新型的“魔蓝”试剂[n-C3F7OCF(CF3)]2N(O)(1)和n-C3F7OCF(CF3)NO2的F113(CCl2FCClF2)溶液,在室温下与一系列对位取代苯甲醛(3)发生攫氢/自旋截捕反应,生成稳定的全氟(1-丙氧基乙基)对位取代苯甲酰基氮氧自由基(4).由自由基4的超精细偶合常数αN和αFβ与取代基的Hammett极性参数和自旋离域参数的相关分析得知,虽然自旋离域因素影响αN值,但取代基的极性是决定αN值的主要因素. 相似文献
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Robert N. MacDonald Allan Cairncross J. B. Sieja W. H. Sharkey 《Journal of polymer science. Part A, Polymer chemistry》1974,12(3):663-678
The recent demonstration of an easy synthesis of diiminosuccinonitrile (DISN) from hydrogen cyanide and cyanogen, the reduction of DISN to diaminomaleonitrile (DAMN), and the use of these compounds to form difunctional heterocycles has made several new polyamide intermediates accessible. The 1- and 2-methyl-1,2,3-triazole-4,5-dicarbonyl chlorides have been polymerized interfacially to form high-melting polyamides of good heat stability. Interfacial polymerization of 1-methylimidazole-4,5-dicarbonyl chloride and trans-2,5-dimethylpiperazine has given a polyamide that is water-soluble. The 2,6- and 2,3-pyrazinedicarbonyl chlorides have been similarly converted to high-melting polyamides. 2,6-Dicyano-3,5-dipiperazinylpyrazine has been prepared from tetracyanopyrazine and piperazine and reacted with toluene diisocyanate to form a strong, stiff polyurea. Polyamides were also made from 2,3-diaminoquinoxaline, 1,4,5,6-tetrahydro-5,6-dioxo-2,3-pyrazinedicarbonitrile, and DAMN. 相似文献
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Romina Marín Abdelilah Alla Sebastin Muoz‐Guerra 《Macromolecular rapid communications》2006,27(22):1955-1961
Summary: The formation of stereocomplexes from the pair of enantiomorphs of the chiral polyamide poly(hexamethylene di‐O‐methyl tartaramide) was investigated for a variety of experimental conditions. DSC and X‐ray diffraction data evidenced that efficiency in enantiomeric association is highly sensitive to the procedure used for preparing the complex. A comparative isothermal crystallization study revealed that the stereocomplex crystallized from the melt at a rate lower than the enantiomerically pure components. The radial growth of individual spherulites was also delayed in the crystallization of the complex. No evidence of stereocoupling was detected for other poly(alkylene di‐O‐methyl tartaramide)s with the alkylene unit length different from six. It was concluded that molecular interlocking of hydrogen bonds in the enantiomeric pair is highly selective in this family of polymers.
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The isolation and characterisation of two fish attractants, a new dipeptide (Arcamine, hypotauryl-2-carboxyglycine),1 and Strombine (C-methyl-imino diacetic acid),2 are described. 相似文献
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As the integration of microfluidics into cell biology research proceeds at an ever-increasing pace, a critical question for those working at the interface of both disciplines is which device material to use for a given application. While PDMS and soft lithography methods offer the engineer rapid prototyping capabilities, PDMS as a material has characteristics that have known adverse effects on cell-based experiments. In contrast, while polystyrene (PS), the most commonly used thermoplastic for laboratory cultureware, has provided decades of grounded and validated research conclusions in cell behavior and function, PS as a material has posed significant challenges in microfabrication. These competing issues have forced microfluidics engineers and biologists to make compromises in how they approach specific research questions, and furthermore, have attenuated the impact of microfluidics on biological research. In this review, we provide a comparison of the attributes of PDMS and PS, and discuss reasons for their popularity in their respective fields. We provide a critical evaluation of the strengths and limitations of PDMS and PS in relation to the advancement and future impact on microfluidic cell-based studies and applications. We believe that engineers have a responsibility to overcome any challenges associated with microfabrication, whether with PS or other materials, and that engineers should provide options and solutions that assist biologists in their experimental design. Our goal is not to advocate for any specific material, but provide guidelines for researchers who desire to choose the most suitable material for their application, and suggest important research directions for engineers working at the interface between microfabrication technology and biological application. 相似文献
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Abas SA Hossain MB van Der Helm D Schmitz FJ Laney M Cabuslay R Schatzman RC 《The Journal of organic chemistry》1996,61(8):2709-2712
Two new alkaloids, polycarpine (1) and N,N-didesmethylgrossularine-1 (4), have been isolated from extracts of the ascidian Polycarpa aurata collected in Chuuk, Federated States of Micronesia. Three degradation products of 1 were also isolated. The structures of 1, 2, and 4 were determined by X-ray crystallography. The dimeric disulfide 1 inhibited the enzyme inosine monophosphate dehydrogenase, but the inhibition could be reversed by addition of excess dithiothreitol suggesting that 1 reacts with sulfhydryl groups on the enzyme. 相似文献
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In this review, information on the production of isoxazolines and condensed isoxazoline systems by the intramolecular 1,3-bipolar cycloaddition of unsaturated nitrile N-oxides generated in situ from nonconjugated nitroalkenes is generalized and systematized. The isoxazoline derivatives formed as the result of these reactions are promising synthons in the synthesis of various natural compounds and their analogues.Krakow Polytechnic Institute, Poland. Translated from Khimiya Prirodnykh Soedinenii, Nos. 3,4, pp. 291–305, May–August, 1992. 相似文献