21064-48-2Relevant academic research and scientific papers
Acceptorless dehydrogenative condensation: synthesis of indoles and quinolines from diols and anilines
Bellezza, Delia,Zaragozá, Ramón J.,José Aurell,Ballesteros, Rafael,Ballesteros-Garrido, Rafael
supporting information, p. 677 - 683 (2021/02/06)
The use of diols and anilines as reagents for the preparation of indoles represents a challenge in organic synthesis. By means of acceptorless dehydrogenative condensation, heterocycles, such as indoles, can be obtained. Herein we present an experimental and theoretical study for this purpose employing heterogeneous catalysts Pt/Al2O3and ZnO in combination with an acid catalyst (p-TSA) and NMP as solvent. Under our optimized conditions, the diol excess has been reduced down to 2 equivalents. This represents a major advance, and allows the use of other diols. 2,3-Butanediol or 1,2-cyclohexanediol has been employed affording 2,3-dimethyl indoles and tetrahydrocarbazoles. In addition, 1,3-propanediol has been employed to prepare quinolines or natural and synthetic julolidines.
Ruthenium-catalyzed synthesis of indoles from anilines and epoxides
Pena-Lopez, Miguel,Neumann, Helfried,Beller, Matthias
supporting information, p. 1818 - 1824 (2014/03/21)
A general synthetic route to indoles from readily available anilines and epoxides by using ruthenium catalysis is described. This straightforward transformation allows a variety of indoles to be obtained in good yields by using [Ru3(CO)12]/1,1-bis(diphenylphosphino)ferrocene as the catalytic system. Water and hydrogen are formed as the only stoichiometric by-products, making this process highly atom efficient.
Improved indole syntheses from anilines and vicinal diols by cooperative catalysis of ruthenium complex and acid
Zhang, Min,Xie, Feng,Wang, Xiaoting,Yan, Fengxia,Wang, Ting,Chen, Mengmeng,Ding, Yuqiang
, p. 6022 - 6029 (2013/05/09)
By developing a new and efficient dinuclear catalyst [Ru(CO) 2(Xantphos)]2 [Xantphos = 4,5-bis(diphenylphosphino)-9,9- dimethyl-9H-xanthene], an improved synthesis of indole from vicinal diols and anilines by cooperative catalysis of ruthenium complex and p-TSA (para-toluenesufonic acid) has been demonstrated. The presented synthetic protocol allows assembling a wide range of products in an efficient manner. Comparing to the existed protocols, our indole syntheses can be achieved at lower reaction temperature, in shorter reaction time, and with improved substrate tolerance.
N-Heterocyclization of naphthylamines with 1,2- And 1,3-Diols catalyzed by an iridium Chloride/BINAP system
Aramoto, Hiroomi,Obora, Yasushi,Ishii, Yasutaka
scheme or table, p. 628 - 633 (2009/06/28)
Benzoquinoline derivatives were successfully synthesized by iridium-catalyzed N-heterocyclization of naphthylamines with diols. For instance, the reaction of 1-naphthylamine with 1,3-propanediol catalyzed by IrCl3 combined with BINAP as a ligand produced 7,8-benzoquinoline in quantitative yield. The VV-heterocyclization reaction was found to be markedly influenced by the ligands employed. Benzoindoles were also synthesized by the same strategy from napthylamines with 1,2-diols. A reaction mechanism for the N-heterocyclization of naphthylamines with 1,3-diols by IrCl3 was proposed.
