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重氮盐是日益广范应用的光敏和热敏材料。国内外学者对重氮盐热解稳定性等问题的研究早有报道.前人研究认为:重氮盐热分解时发生C—N键的断裂,分为异裂和均裂两种.在酸性水溶液中为异裂反应,生成芳烃正离子;在碱性水溶液或醇溶液中,大多发生均裂反应,生成游离基.Brown及角田等研究发现:在苯环重氮基对位上引入强正极性基能增加重氮盐的热稳定性,但Crossley等人发现,在重氮基对位上的取代基,无论是吸电子的硝基(-NO_2)或是给电子的甲氧基(-OCH_3),都能增加重氮盐的热稳定性.然而人们还未能从理论上对于上述问题予以深入明确的探讨.取代基的不同、热解产物的不同以及 相似文献
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合成了几种芳香重氮盐感光材料,发现1的最大吸收峰位于343 nm,与355 nm激光器的光谱能很好地重叠.2和3的吸收光谱分别红移至453 nm和 433 nm,在可见光范围内与高压汞灯有很大的光谱重叠.2具有比3更好的热稳定性及快速的光分解速度. 相似文献
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取代苯可与烯类发生:[2+2],[3+2]和[4+2]三种类型的光环加成反应,本文重点阐述[2+2]与[3+2]光环加成反应的选择性-周环选择性,及反应在取代苯的什么位置上进行-区位选择性,及取代烯类取代基的内型与外型-立体选择性。 相似文献
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C60的[3+2]环加成反应 总被引:2,自引:0,他引:2
综述了C60的[3+2]环加成反应的研究进展。包括C60与亚胺叶立德、重氮化合物、叠氮化合物、氧化腈、腈亚胺、cis-HOCH2CH=CHCH2OCO2Et、1,8-二碘萘、环丙烯酮缩醛和Pyrazolidinium叶立德发生的[3+2]环加成反应。 相似文献
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长期以来,我们一直在研究化合物的性能与结构关系的定量化问题,其目的是为了寻求一个定量确定反应物反应活性的简易方法。本文研究了一种确定环加成反应区域选择性的新方法。早在七十年代初期,对于环加成反应的区域选择性问题就有报导,可以通过分子轨道法等加以确定。但是,应用分子轨道法的计算程序过于繁琐,所以应用并不广泛。1989年,S.K.Pal提出了处理这个问题的一个方程,即可以通过活性中心原有的电负性进行推算。这种原有的电负性可以用Huheey方法计算,但是这种计算方法在应用中仍然是相当复杂 相似文献
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本文回顾了分子间Diels-Alder反应的定义和类型,详细总结了自由基正离子催化的Diels-Alder环加成反应方式,包括铵基阳离子、电化学、三价铁和光催化等方法,对不同催化体系的优缺点进行了说明。同时总结了自由基正离子Diels-Alder环加成反应的现状、面临的挑战,以及未来的发展趋势。 相似文献
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Aryl diazonium salts occupy a privileged role in synthetic chemistry owing to their ready availability and versatile reactivity. While their applications in accessing diversely functionalized arene derivatives via denitrogenation‐coupling and reduction/addition reactions have been well recognized by practitioners in both academia and industry, recent renaissance in chemical transformations of retaining the key N2‐unit has emerged as a powerful technique to construct various N‐heterocycles. This review covers the history and latest advances in cyclization and cycloaddition reactions using aryl diazonium salts as N2‐annulation synthons. The scope, applications, and opportunities in exploring new chemical space by this sustainable strategy are summarized and discussed. 相似文献
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Samuel Andrejčák Dr. Péter Kisszékelyi Dr. Michal Májek Prof. Dr. Radovan Šebesta 《European journal of organic chemistry》2023,26(5):e202201399
Arylboronates are helpful building blocks in organic synthesis. Here, we present an efficient mechanochemical synthesis of arylboronates from arene diazonium salts. Importantly, this transformation was significantly enhanced by sodium chloride, which probably promotes the decomposition of diazonium salts via anion exchange. Chloride anions also participate in the formation of strongly reducing Cl−B anion radical intermediate that promotes radical chain reaction. The reaction proceeds more efficiently with a small amount of polar solvent as a liquid-assisted grinding additive. Quantum chemical calculations support the mechanistic proposal. 相似文献
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Jiang Wu Yang Gu Dr. Xuebing Leng Prof. Dr. Qilong Shen 《Angewandte Chemie (International ed. in English)》2015,54(26):7648-7652
An efficient copper‐promoted difluoromethylthiolation of aryl and heteroaryl diazonium salts is described. The reaction is conducted under mild reaction conditions and various functional groups were compatible. In addition, reactions of heteroaryl diazonium salts such as pyridyl, quinolinyl, benzothiazolyl, thiophenyl, carbazolyl, and pyrazolyl diazonium salts occurred smoothly to afford the medicinally important difluoromethylthiolated heteroarenes. Furthermore, a more practical one‐pot direct diazotization and difluoromethylthiolation protocol was developed, and it converts the aniline derivatives into difluoromethylthiolated arenes. The utility of the method is demonstrated by difluoromethylthiolation of a number of natural products and drug molecules. 相似文献
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M. Sc. Durga Prasad Hari Prof. Dr. Burkhard König 《Angewandte Chemie (International ed. in English)》2013,52(18):4734-4743
The use of diazonium salts for aryl radical generation and C? H arylation processes has been known since 1896 when Pschorr first used the reaction for intramolecular cyclizations. Meerwein developed it further in the early 1900s into a general arylation method. However, this reaction could not compete with the transition‐metal‐mediated formation of C(sp2)? C(sp2) bonds. The replacement of the copper catalyst with iron and titanium compounds improved the situation, but the use of photocatalysis to induce the one‐electron reduction and activation of the diazonium salts is even more advantageous. The first photocatalyzed Pschorr cyclization was published in 1984, and just last year a series of papers described applications of photocatalytic Meerwein arylations leading to aryl–alkene coupling products. In this Minireview we summarize the origins of this reaction and its scope and applications. 相似文献
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Substituted aryl diazonium fluoroborates have been selectively reduced to the corresponding phenylhydrazines by using borohydride exchange resin (BER). 相似文献
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Céline A. Mandon Dr. Loïc J. Blum Prof. Christophe A. Marquette Dr. 《Chemphyschem》2009,10(18):3273-3277
A method for the immobilization of proteins at the surface of surface plasmon resonance imaging (SPRi) chips is presented. The technology, based on the electro‐deposition of a 4‐carboxymethyl aryl diazonium (CMA) monolayer is compared to a classical thioctic acid self‐assembled monolayer. SPRi live recording experiments followed by the quantification of the diazonium surface coverage demonstrate the presence of a monolayer of electro‐deposited molecules (11*1012 molecules mm?²). This monolayer, when activated through a classical carbodiimide route, generates a surface suitable for the protein immobilization. In the present study, protein A and BSA are immobilized as specific and control spots (150 μm id), respectively. The AFM characterization of the spots deposited onto CMA or thioctic acid modified chips prove the presence of 4.7 nm protein monolayers. Finally, the SPRi detection capabilities of the two surface chemistries are compared according to specific signal, non‐specific interaction and regeneration possibilities. Advantages are given to the CMA surface modification since no measurable non‐specific signal is obtained while reaching a higher specific signal. 相似文献