共查询到20条相似文献,搜索用时 0 毫秒
1.
A simple, efficient, and rapid method for high-yielding regioselective mono bromination of phenols and anilines has been achieved by treatment with N-bromasaccharin in the presence of a catalytic amount of tungstophosphoric acid. 相似文献
2.
A simple, efficient, and mild method for selective bromination of some activated aromatic compounds using potassium bromide in the presence of benzyltriphenylphosphonium peroxodisulfate in nonaqueous solution is reported. The results obtained revealed good to excellent selectivity between ortho and para positions of phenols and methoxyarenes. 相似文献
3.
N-Benzyl-DABCO tribromide, a stable, solid organic ammonium tribromide, has been used as a bromine source for the regioselective and high-yielding bromination of aromatic amines and phenols. Mono-bromination proceeds well in the presence of a stoichiometric amount of bromine source at room temperature. 相似文献
4.
芳香胺和酚溴化的新工艺 总被引:1,自引:0,他引:1
研究了在室温下,N-溴丁二酰亚胺对芳香胺和酚的溴化工艺,在CHCl3、EtOH或EtOH/CHCl3溶剂中,用等摩尔的N-溴丁二酰亚胺可将某些芳香胺和酚(考察了5种反应底物)选择性地一溴化,产率92%~98%,N-溴丁二酰亚胺和反应底物摩尔比为2∶1;某些芳香胺和酚被专一地二溴化(考察了5种反应底物),产率90%~97%。 反应无须催化剂,投料后室温搅拌,反应条件温和,产品只需过滤洗涤即可纯化,操作简便。 相似文献
5.
A mild and selective procedure for the bromination of activated arenes using o-iodoxybenzoic acid and tetraethylammonium bromide is presented. The reactions were carried out at room temperature and gave moderate to excellent yields. 相似文献
6.
Reaction of substituted benzene rings with N‐bromophthalimide, under neutral conditions, gave the corresponding bromo derivatives with a preference for the formation of the para bromo isomer over the ortho isomer. The simple work‐up procedure minimizes loss of product and the yields are good. 相似文献
7.
8.
9.
HongMinMA ZhanZhuLIU ShiZhiCHEN 《中国化学快报》2003,14(4):371-374
The selective brominationsd of 3,4-dimethoxytoluene with N-bromosuccinimide were reported.The nuclear and side-chain brominated products were obtained under different reaction conditions.The mechanism was also discussed. 相似文献
10.
Yu Lin JIANG 《中国化学快报》1998,(1)
Thedirectintroductionofbromineintotheringsofaromaticethersisawell-establishedprocedure,withbromineinasuitablesolventsuchascarbontetrachloride'oraceticacid2.Recently,quatemaryammoniumsaltswerefoundtobeusedasco-catalystforthedirectbrominationofanilinederivatives3.Thus,quaternaryammoniumtribro-mide,acomplexofquatemaryammoniumbromideandbromine4couldbeappliedforbrominationofaromaticethers5'6.However,theproceduresareverytroublesomeandunsafe.RozenandBrand'reportedthatbrominefluoridecouldbeappliedasa… 相似文献
11.
12.
Bromination of different aromatic substrates have been described using 2,4,4,6‐tetrabromo‐2,5‐cyclohexadienone in conjunction with microwave and ultraviolet radiations. Important features of the work include high regioselectivity obtained in very short to moderate reaction time, atom economy, and recyclability of the reagent. 相似文献
13.
Tadej Stropnik 《Tetrahedron letters》2008,49(11):1729-1733
A regioselective method for the bromination of phenols, ethers and anilines using a ZrBr4/diazene mixture is described. The reaction takes place under mild reaction conditions and the bromine atom adds first at the para unsubstituted position with respect to the OH, OR or NR2 group of the activated aromatic substrate. Less reactive compounds such as toluene, phenyl acetate, benzonitrile and trifluoromethylbenzene remain intact under the same conditions. 相似文献
14.
Hexamethylene bis(N-methylimidazolium) bis(dichloroiodate) (HMBMIBDCI), an ionic liquid iodinating reagent, have been prepared and characterized. Its ability to perform iodination reactions with a variety of substrates has been explored. In general, iodination reactions of aromatic and heteroaromatic amines proceed with good yields in the absence of solvent. Reactions of terminal alkynes in the presence of 1,8-diazabicyclo [5.4.O] undec-7-ene and tetrahydrofuran have been investigated as well. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource: Full experimental and spectral details.] 相似文献
15.
D. E. Chumakov A. V. Khoroshutin A. V. Anisimov K. I. Kobrakov 《Chemistry of Heterocyclic Compounds》2009,45(3):259-283
Methods for the bromination of porphyrins and their derivatives at the meso and β-positions are examined. The dependence of the course of the reactions on the conditions and on the structure of the
initial compounds is discussed.
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 323-353, March, 2009. 相似文献
16.
17.
A mild and expeditious method for α‐bromination of 1,3‐dicarbonyl compounds using Dess–Martin periodinane and tetraethylammonium bromide is described. 相似文献
18.
19.
Qiang Chen Di Wang Martin Baumgarten Dieter Schollmeyer Klaus Müllen Akimitsu Narita 《化学:亚洲杂志》2019,14(10):1703-1707
Dibenzo[hi,st]ovalene (DBOV) is a nanographene with a combination of zigzag and armchair edges, consisting of 38 sp2 carbons. Excellent optical properties with strong red emission have been demonstrated. Here we report the regioselective bromination of DBOV bearing two mesityl groups ( DBOV‐Mes ) by treatment with N‐bromosuccinimide (NBS) under mild conditions. The dibrominated DBOV was further subjected to transition‐metal‐catalyzed cross‐coupling reactions, that is, Suzuki and Sonogashira coupling, demonstrating the edge‐decoration of DBOV with different functional groups. Notably, DBOVs arylated at the bay regions showed intense red emission and enhanced fluorescence quantum yields of up to 0.97. Amphoteric reduction and oxidation behavior were observed by cyclic voltammetry (CV) measurements. Chemical oxidation to stable radical cation species was also demonstrated, followed by reduction back to their neutral species. 相似文献
20.
Gram‐Scale Synthesis and Highly Regioselective Bromination of 1,1,9,9‐Tetramethyl[9](2,11)teropyrenophane
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Kiran Sagar Unikela Dr. Tracey L. Roemmele Václav Houska Kaitlin E. McGrath David M. Tobin Prof. Louise N. Dawe Prof. René T. Boeré Prof. Graham J. Bodwell 《Angewandte Chemie (International ed. in English)》2018,57(6):1707-1711
An improved synthetic pathway to the nanobelt‐like 1,1,9,9‐tetramethyl[9](2,11)teropyrenophane has been developed, and enables the synthesis of gram quantities of material. Key innovations are the development of a sequential chlorination/Friedel–Crafts alkylation reaction, a sequential iodination/Wurtz coupling reaction, and a room‐temperature teropyrene‐forming reaction. The teropyrenophane was found to form a very stable radical cation and undergo a completely regioselective fourfold bromination reaction. 相似文献