100986-21-8Relevant articles and documents
Iron(II)-Catalyzed Aerobic Biomimetic Oxidation of N-Heterocycles
Manna, Srimanta,Kong, Wei-Jun,B?ckvall, Jan-E.
, p. 13725 - 13729 (2021)
Herein, an iron(II)-catalyzed biomimetic oxidation of N-heterocycles under aerobic conditions is described. The dehydrogenation process, involving several electron-transfer steps, is inspired by oxidations occurring in the respiratory chain. An environmentally friendly and inexpensive iron catalyst together with a hydroquinone/cobalt Schiff base hybrid catalyst as electron-transfer mediator were used for the substrate-selective dehydrogenation reaction of various N-heterocycles. The method shows a broad substrate scope and delivers important heterocycles in good-to-excellent yields.
Fischer indole synthesis in bronsted acidic ionic liquids: A green, mild, and regiospecific reaction system
Xu, Dan-Qian,Yang, Wen-Long,Luo, Shu-Ping,Wang, Bing-Tao,Wu, Jian,Xu, Zhen-Yuan
, p. 1007 - 1012 (2007)
A novel one-pot Fischer indole synthesis approach has been developed by using Bronsted acidic ionic liquids as dual solvent-catalysts. Yields of 83-97 % were obtained after reaction in BMImHSO4 at 70-110°C in 0.5-6 h, and exclusive formation of 2,3-disubstituted indoles was observed in the reaction of alkyl methyl unsymmetrical ketones. The indoles produced could be conveniently separated from the reaction mixture without any volatile organic solvents, and the BMImHSO4 could be readily reused without efficiency loss after simple treatment involving only 1 equiv. of HCl for neutralization followed by filtration. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
Total Synthesis of (-)-Alloaristoteline, (-)-Serratoline, and (+)-Aristotelone
Stoermer, Doris,Heathcock, Clayton H.
, p. 564 - 568 (1993)
The Aristotelia alkaloids (-)-alloaristoteline (4), (-)-serratoline (12), and (+)-aristotelone (13) have been prepared as summarized in Scheme IV.Thus, via the method of Stevens, (1S)-(-)-β-pinene (9) and 3-indolylacetonitrile (10) were coupled by a Hg(NO3)2-mediated Ritter reaction followed by reduction of the resulting imine to give (+)-makomakine (11).An intramolecular Friedel-Crafts reaction delivered (+)-aristoteline (3), which was oxidized by reaction with oxygen and platinum.Reduction of the intermediate hydroperoxide delivered alkaloid 12.Base-catalyzed skeletal rearrangement of 12 provided alkaloid 13, which was reduced with LiAlH4 to obtain a mixture of secondary alcohols, 14a,b.Treatment of each of these alcohols with HCl in methanol afforded (-)-alloaristoteline (4).
Fischer indole synthesis catalyzed by novel SO3H-functionalized ionic liquids in water
Xu, Dan-Qian,Wu, Jian,Luo, Shu-Ping,Zhang, Ji-Xu,Wu, Jia-Yi,Du, Xiao-Hua,Xu, Zhen-Yuan
, p. 1239 - 1246 (2009)
Novel SO3H-functionalized ionic liquids bearing two alkyl sulfonic acid groups in the imidazolium cations were designed and successfully applied as catalysts for the one-pot Fischer indole synthesis in water medium. The sequence of the catalytic activity observed in the transformation was in good agreement with the Bronsted acidity order determined by the Hammett method. Various types of indoles from single-carbonyl ketones/aldehydes and cyclohexandiones were provided in 68-96% yields using the catalytic system of [(HSO3-p)2im][HSO4]/H2O. The indole products could be conveniently separated from the reaction mixture by filtration and the dissolved catalyst could be regenerated by treatment with a strongly acidic cation exchange resin, which meant the whole process was performed in water without using any organic solvents.
Copper(II) catalyzed aromatization of tetrahydrocarbazole: An unprecedented protocol and its utility towards the synthesis of carbazole alkaloids
Dalvi, Bhakti A.,Lokhande, Pradeep D.
supporting information, p. 2145 - 2149 (2018/05/08)
An efficient protocol for the aromatization of tetrahydrocarbazole is described by using catalytic copper(II) chloride dihydrate in DMSO. This newly established methodology has utilized towards the synthesis of naturally occurring carbazole alkaloids, namely 3-methylcarbazole, 3-formyl carbazole, glycozoline, glycozolicine and clauszoline-K. In addition, the protocol is generalized for the aromatization of N-substituted tetrahydrocarbazole, 1,2,3,4-tetrahydroquinoline, 1,2,3,4-tetrahydroisoquinoline and 1,2,3,4-tetrahydro β-carboline to give the corresponding heteroaromatic compounds from very good to excellent yield. Moreover, this method has been proven to be tolerant to a broad range of functional groups with excellent yields.
Method for preparing indole compounds through catalysis of ionic liquid
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Paragraph 0034-0036, (2018/02/04)
The invention relates to a green synthesis method of one type of indole derivatives. The method is characterized by taking sulfonic acid ionic liquid as a catalyst, taking aliphatic ketone, aromatic ketone and aromatic hydrazine hydrochloride as raw materials, reacting in water, filtering and drying a reaction mixture to obtain indole compounds. The method is simple to operate; the raw materials are low intoxicity and low in costs; the reaction condition is mild; the product is easy to separate; the synthesis process is environmentally-friendly; the indole compounds are high in purity; the catalyst can be directly reused without treatment; the method is green and environmentally-friendly, and is suitable for industrial production.
