Dimerizations of 2-bromo-3-methyl-1,4-naphthoquinone and 2-methyl-1,4-naphthoquinone in tetra-n-butylammonium bromide
Dimerizations of 2-bromo-3-methyl-1,4-naphthoquinone and 2-methyl-1,4-naphthoquinone in tetra-n-butylammonium bromide
复制标题
DOI：
10.1016/j.tet.2019.130899
复制
发表时间：
2020-02-07
期刊：
影响因子：
2.1
通讯作者：
Kuramochi, Kouji
中科院分区：
文献类型：
--
作者：
Onuki, Mai;Ota, Motohiro;Kuramochi, Kouji
2-溴-3-甲基-1，4-萘酚和2-甲基-1，4-萘酚是已知的以各种方式进行二聚的高活性物种。每种化合物的二聚化产物主要取决于所用的溶剂。离子液体代表了一类具有非分子(离子)性质的新型溶剂。用离子溶剂取代传统的有机溶剂往往会改变反应的机理。本文研究了2-溴-3-甲基-1，4-萘酚与2-甲基-1，4-萘酚在离子液体中的反应。2-溴-3-甲基-1，4-萘酚或2-甲基-1，4-萘酚与N-甲基环己胺在离子液体四丁基溴化铵(TBAB)中在好氧气氛下进行二聚反应，分别得到5，7，12，14-五环三酮和1-甲基库喹酮。与以前报道的方法相比，使用四叔丁基溴化铵作为溶剂提高了产品的产率。并对各二聚反应的机理进行了探讨。(C)2019爱思唯尔有限公司。保留所有权利。
2-Bromo-3-methyl-1,4-naphthoquinone and 2-methyl-1,4-naphthoquinone are highly reactive species known to dimerize in various ways. The product obtained in the dimerization of each compound is primarily dependent upon the solvent used. Ionic liquids represent a new class of solvents having non-molecular (ionic) character. Replacement of a conventional organic solvent with an ionic solvent frequently changes the mechanism of a reaction. In this study, reactions of 2-bromo-3-methyl-1,4-naphthoquinone and 2-methyl-1,4-naphthoquinone in ionic liquids were examined. Dimerization of 2-bromo-3-methyl-1,4-naphthoquinone or 2-methyl-1,4-naphthoquinone with N-methylcyclohexylamine in tetra-n-butylammonium bromide (TBAB), an ionic liquid, under an aerobic atmosphere afforded 5,7,12,14-pentacenetetrone and 1-methylKuQuinone, respectively. The use of TBAB as a solvent improved the yields of the products as compared with previously reported methods. The mechanism of each dimerization was also investigated. (C) 2019 Elsevier Ltd. All rights reserved.