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将重氮化合物的水溶液加热水解以制取酚,是实验室中制备酚最简便的方法。例如,由苯胺经重氮化后,再水解即得苯酚是这类反应中典型的例子。一般有机实验书中,总是将重氮苯硫酸鉴水溶液先加热水解、再进行水蒸汽蒸馏。由于生成的酸与未分解的重氮化物偶合,生成脂状产物,往往得不到满意的产量。Lambooy(注)改进了操作手续,将重氮盐的水解与水蒸汽蒸馏同时进行,不但省略了一道手续,而且使产量 相似文献
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1.将十二种芳伯胺和亚硝酸正丁酯或异戊酯在沸苯溶液中反应,合成联苯、各种异构的甲基-、氯-和硝基-联苯以及苯基萘。产率令人满意。2.基于各种因素对联苯产率的影响的详细研究,找出用于合成的最适宜条件。3.实验证明在反应中产生的氢氧化重氮化合物与芳(?)胺偶合而生成的重氮氨基化合物是反应的中间产物之一。但氢氧化重氮化合物直接与苯作用而生成联苯和芳基苯也是可能的;这是在稀溶液中反应的主要途径。反应产物的生成可能是自由基历程。 相似文献
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聚苯乙烯基偶氮聚合物的合成研究 总被引:4,自引:0,他引:4
改进了聚苯乙烯的硝化、还原、重氮化和偶合反应路线 (NRDC) ,使每步反应都得到很高的产率 ,并利用大分子重氮盐 (MDS)分别与苯胺、N 烃基苯胺和酚等三类化合物偶合 ,得到相应的聚苯乙烯基偶氮聚合物 .核磁共振分析结果证明了产物的高偶联率 .通过对大分子重氮盐热稳定性的研究 ,发现偶合反应之后需要一步加热反应以消除残余重氮基团 .还研究了这些聚合物的紫外 可见吸收光谱性质 ,氨 (胺 )基偶氮产物的水溶液表现出了明显的pH敏感性 相似文献
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在水溶液中,很多试剂,如浓硝酸,Cu~(++)/Py,Bi_2O_3/H~+,Fe(CN)_6~(3-)/OH~-等可将苯偶姻(Benzoin)氧化生成苯偶酰(Benzil),而在有机介质且中性条件下反应的例子不多。Ho曾报道,Ph_3P·Br_2在无水乙腈中能氧化苯偶姻制得苯偶酰,产率75~98%。Swern还使用过Me_2SO/(COCl)_2/CH_2Cl_2,产率64~95%。 相似文献
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《化学学报》2015,(11)
尽管近年来有关受限路易斯酸碱对(FLPs)化学的研究受到了国内外的广泛关注,但有关芳香胺类FLPs的应用研究却极少涉及.设计了一种研究芳香胺类FLPs的新型方法,以芳香胺盐酸盐与路易斯酸三(五氟苯基)硼(BCF)组成新的反应体系,以氢化硅烷作为氢源.研究了在计量条件下一系列芳香胺盐酸盐/BCF体系与硅烷的反应特征.与烷基胺盐酸盐/BCF体系所不同的是,芳香胺盐酸盐/BCF体系在溶液中与氢化硅烷反应时所形成的芳香硼氢化胺盐[Ar_2NH_2]+[HBCF]-由于不稳定,在反应过程中会立即释放出氢气,并分解为芳胺和BCF.但是,恰恰是由于硼氢化芳香胺盐分解后重新产生的BCF,使得这类体系可用于催化反应,可作为一种新型高效的非金属催化体系用于硅烷的氯代反应.本文对在BCF的催化下,芳香胺盐酸盐与氢化硅烷在不同比例下反应,制备单氯或二氯代硅烷的反应过程及机理也做了详细地研究.同时,根据实际需要,可在反应结束后向反应体系中通入HCl气体的方法实现原料芳胺盐酸盐的重新利用,更加绿色环保. 相似文献
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苯骈咪唑-N-Mannich碱与苯乙酮的交换反应 总被引:3,自引:0,他引:3
Mannich反应是在有机合成中广泛采用的反应,是甲醛与胺及含有活性氢的分子(如甲基酮等)发生缩合反应,是制备β-胺基酮类的方便方法.但一般认为芳香胺不能参加这个反应,因此,可先制成脂肪胺的Mannich碱,然后用芳香胺交换来制备β-芳胺基酮[1-5]. 相似文献
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用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%. 相似文献
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Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields. 相似文献
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Uroš Grošelj Mojca Žorž Amalija Golobič Branko Stanovnik Jurij Svete 《Tetrahedron》2013,69(52):11092-11108
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives. 相似文献
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The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion. 相似文献
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A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL. 相似文献
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Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction
Laurent Gavara Thomas Boisse Jean-Pierre Hénichart Adam Daïch Philippe Gautret 《Tetrahedron》2010,66(38):7544-5571
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments. 相似文献
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A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions. 相似文献
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N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%). 相似文献
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Shashikant U. Dighe Surya K. Samanta Shivalinga Kolle Sanjay Batra 《Tetrahedron》2017,73(17):2455-2467
An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y1 and Y2. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones. 相似文献
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In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates. 相似文献