共查询到20条相似文献,搜索用时 46 毫秒
1.
2.
3.
4.
近几年来, 过渡金属催化的碳氢键活化的三氟甲基化反应取得了重要的进展. 该领域的反应主要集中于端炔的sp碳氢键活化三氟甲基化反应、芳烃和杂环的sp2碳氢键活化的三氟甲基化反应以及烯丙基sp3碳氢键活化的三氟甲基化反应. 本文简要介绍了该类反应的特点, 概述了该领域的最新进展、面临的挑战及以后研究发展的重点和方向. 相似文献
5.
含氟杂环化合物由于其优异的物理化学性质,在有机化学、药物化学、材料科学等诸多领域扮演着重要的角色.但自然界中,天然含氟杂环化合物屈指可数,开发高效的含氟杂环化合物的合成方法显得尤为重要.随着过渡金属催化、光催化以及电催化自由基反应的迅速发展,自由基化学在合成领域取得了突破性进展,激发了有机化学家利用自由基化学构建含氟杂环的兴趣.主要以不饱和烃的单氟烷基化、二氟烷基化、三氟甲基化、三氟烷氧/硫/硒基化、全氟烷基化以及杂环的直接C—H氟烷基化进行分类,从过渡金属催化、光催化以及电催化等几个方面,对自由基介导的含氟侧链杂环化合物的构建进行讨论. 相似文献
6.
全氟烷基化反应,特别是三氟甲基化反应一直是有机化学领域的研究热点。近几年来,可见光促进的光氧化还原催化的有机化学反应,因其本身所固有的条件温和、绿色和环保等优点而倍受合成化学家的青睐。该方法学也被成功地应用于一系列三氟甲基化反应。本文主要按照三氟甲基源分类,总结了近年来可见光促进的光氧化还原催化的三氟甲基化反应的研究进展,并对其发展趋势进行了展望。 相似文献
7.
三氟甲基的选择性碳氟键活化是获得偕二氟类化合物的重要途径.鉴于三氟甲基烯烃在合成上的重要性以及反应选择性的多样性,近年来利用这类化合物的选择性碳氟键活化引起了极大的关注.综述了这一领域的研究进展,主要包括亲核加成/脱氟反应(SN2’类型)、酸促进的脱氟傅克芳基化反应、(形式)原位脱氟官能团化反应以及过渡金属催化的迁移插入/脱氟反应. 相似文献
8.
9.
10.
在温和的铜盐促进反应条件下,四氮杂杯[1]芳烃[3]吡啶化合物发生高效、高选择性芳香碳氢键三氟甲基化反应,高产率地生成了一系列三氟甲基官能化的大环分子.基于结构明确的芳基二价铜和芳基三价铜的三氟甲基化反应的结果,铜促进的芳香碳氢键三氟甲基化反应依据三氟甲基化试剂的性质经历了两条完全不同的途径.当使用亲核性的Ruppert-Prakash试剂时,芳基三价铜与三氟甲基阴离子生成[ArCu(Ⅲ)CF3]+配合物及发生还原消除是反应的关键步,而当使用亲电性的Umemoto试剂时,反应经历了芳基二价铜与三氟甲基自由基的直接偶联过程. 相似文献
11.
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
12.
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
13.
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
14.
The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula. 相似文献
15.
Rebecca J. Burton Mandy L. CrowtherNeal J. Fazakerley Shaun M. FilleryBarry M. Hayter Jason G. KettleCaroline A. McMillan Paula PerkinsPeter Robins Peter M. SmithEmma J. Williams Gail L. Wrigley 《Tetrahedron letters》2013
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines. 相似文献
16.
KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields. 相似文献
17.
N. A. Nedolya 《Chemistry of Heterocyclic Compounds》2008,44(10):1165-1219
The review contains a concise historical account and information on the most significant researches undertaken by the staff
at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry
of Heterocyclic Compounds.
Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee.
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008. 相似文献
18.
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
19.
Regiospecific and direct imidation of the methyl C(sp3)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products. 相似文献
20.
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