<i>N</i>-Bromosuccinimide (NBS)-Catalyzed C–H Bond Functionalization: An Annulation of Alkynes with Electron Withdrawing Group (EWG)-Substituted Acetyl Indoles for the Synthesis of Carbazoles

Wang, Han; Wang, Zhen; Wang, Yilong; Zhou, Rui-Rui; Wu, Guang-Chuan; Yin, Si-Yao; Yan, Xu; Wang, Bin

doi:10.1021/acs.orglett.7b03021

Cited by 39 publications

(12 citation statements)

References 92 publications

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“…In one approach, N ‐bromosuccinimide‐catalyzed the carbon‐hydrogen bond functionalization of indolyl oxonitriles with terminal and internal alkynes to give carbazoles 40 (Scheme 23). [65] The reaction was compatible with a wide range of terminal substituted aryl alkynes; however, alkyl, heteroaryl, and internal alkynes gave the carbazoles in poor yields. The reaction mechanism was studied in details indicating that the reaction starts with an oxidation of NBS and bromination of acetyl indole to give a bromide intermediate, followed by coupling with an alkyne and an intramolecular cycloaromatization to afford the carbazole products.…”

Section: Synthesis Of Carbazolesmentioning

confidence: 94%

Recent Developments in the Cyclization of Alkynes and Nitrogen Compounds for the Synthesis of Indole Derivatives

Neto

Zeni

2021

Asian J Org Chem

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This review is intended to highlight the most useful approaches for the synthesis of indole derivatives (azaindoles, carbazoles, carbolines, indazoles, 3H-indoles, indolines, indolizines, isoindoles, and isoindolines), which were described by using transition-metal catalyzed cyclization reactions of alkynes and nitrogen compounds. The methodologies carried out under metal-free conditions will also be illustrated herein. This review will cover the data published mostly in the past decade. Synthesis of 6-AzaindolesAzaindoles, although rare in nature, have attracted a significant attention because some synthetic structures containing this nucleus exhibit biological activities. [17] The synthetic methods describing the preparation of azaindoles are limited. Usually their synthesis was achieved from the cyclization reaction of substrates containing aminopyridines. [18] Transition Metal-Free Synthesis of 6-AzaindolesWe have nominated two methodologies for the preparation of 6-azaindoles, which were developed using alkynes and nitrogen compounds in a metal-free protocol. In the first, an electrophilic cyclization condition, using iodine as an electrophilic source, was applied to 2-(azidomethyl)-3-alkynyl-pyrroles in the preparation of 4-iodo-6-azaindoles 1 (Scheme 1, eq 1). [19] The second approach described the preparation of 2,5-disubstituted 6azaindoles 2 from base-catalyzed intramolecular cyclization of 2-(azidomethyl)-3-alkynyl-pyrroles (Scheme 1, eq 2). [20] 3. Synthesis of 7-Azaindoles Transition Metal-Catalyzed Synthesis of 7-Azaindoles Silver-Catalyzed Synthesis of 7-AzaindolesSilver-catalyzed cyclization reactions of alkynes constitute powerful strategies for the construction of heterocycles. In particular, the 7-azaindoles could be obtained by these approaches. A general method for the preparation of aryl-[a] Dr. J.

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Section: Synthesis Of Carbazolesmentioning

confidence: 94%

Recent Developments in the Cyclization of Alkynes and Nitrogen Compounds for the Synthesis of Indole Derivatives

Neto

Zeni

2021

Asian J Org Chem

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“…The formed precipitate on hot was filtered off, dried as a pure compound; colorless crystals with MP 224 –6 °C (reported mp. 224 °C) [ 29 ], yield 65%. 1 H NMR (500 MHz, DMSO-d 6 ) δ= 12.15 (s, NH), 8.33 (s, 1H), 8.10 (d, J = 5 Hz, 1H), 7.48 (d, J = 10 Hz, 1H), 7.22–7.19 (t, J = 15 Hz, 2H), 4.42 (s, CH 2 ).…”

Section: Methodsmentioning

confidence: 99%

“…The resulting α,β-unsaturated ketones 8a-e were converted into the corresponding bis(indolyl)pyridines 7a-e in excellent yields via their reaction with 3-(1H-indol-3-yl)-3-oxopro- First, we reported the synthesis of bis(indolyl)pyridine derivatives incorporated with a simple substituted phenyl. The starting 3-(1H-indol-3-yl)-3-oxopropanenitrile (1) was prepared via the electrophilic substitution reaction of indole with cyanoacetic acid [29]. Condensation of 3-(1H-indol-3-yl)-3-oxopropanenitrile (1) with various substituted aldehydes 2, 3-indolyl methyl ketone (3), and ammonium acetate under reflux in glacial acetic acid following a one-pot four-component domino protocol led to the formation of 2,6bis(1H-indol-3-yl)-4-(substituted-phenyl)pyridin-5-carbonitriles 4a-j (Scheme 1).…”

Section: Chemistrymentioning

confidence: 99%

Synthesis, Molecular Docking, and Biofilm Formation Inhibitory Activity of Bis(Indolyl)Pyridines Analogues of the Marine Alkaloid Nortopsentin

et al. 2021

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An efficient and simple protocol for the synthesis of a new class of diverse bis(indolyl)pyridines analogues of the marine alkaloid nortopsentin has been reported. A one-pot four-component condensation of 3-cyanocarbomethylindole, various aldehyde, 3-acetylindole, and ammonium acetate in glacial acetic acid led to the formation of 2,6-bis(1H-indol-3-yl)-4-(substituted-phenyl)pyridine-5-carbonitriles. Additionally, 2,6-bis(1H-indol-3-yl)-4-(benzofuran) pyridine-5-carbonitriles were prepared via a one-pot four-component condensation of 3-cyanocarbomethylindole, various N-substituted-indole-3-aldehydes, 2-acetylbenzofuran, and ammonium acetate. The synthesized compounds were evaluated for their ability to inhibit biofilm formation against the Gram-positive bacterial reference strains Staphylococcus aureus ATCC 6538 and the Gram-negative strain Escherichia coli ATCC 25922. Some of the new compounds showed a marked selectivity against the Gram-positive and Gram-negative strains. Remarkably, five compounds 4b, 7a, 7c, 7d and 8e demonstrated good antibiofilm formation against S. aureus and E. coli. On the other hand, the release of reducing sugars and proteins from the treated bacterial strains over the untreated strains was considered to explain the disruption effect of the selected compound on the contact cells of S. aureus and E. coli. Out of all studied compounds, the binding energies and binding mode of bis-indole derivatives 7c and 7d were theoretically the best thymidylate kinase, DNA gyrase B and DNA topoisomerase IV subunit B inhibitors.

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“…Recently, owing to ready availability of indoles, synthesis of 4-hydroxylcarbazoles from indole-derived substrates via formation of a phenol ring has emerged as a powerful strategy . To date, a variety of indolyl compounds have been prepared from indoles to serve as a four-, five-, six-carbon synthon (Scheme A). These methods suffer from multistep synthesis of the substrates, high reaction temperature, and/or use of transition metals.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of 4-Hydroxycarbazole Derivatives by Benzannulation of 3-Nitroindoles with Alkylidene Azlactones

Cao

Chen

et al. 2021

ACS Omega

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A general synthesis of 4-hydroxylcarbazoles by domino vinylogous conjugate addition/cyclization/elimination/ aromatization of easily prepared 3-nitroindoles with alkylidene azlactones under mild and transition-metal-free conditions has been developed. This method was also applicable to other nitrosubstituted benzofused heterocycles such as 3-nitrobenzothiophene, 2-nitrobenzothiophene, and 2-nitrobenzofuran. The valuable tetracyclic carbazole derivatives, such as 6H-oxazolo[4,5c]carbazole and 3,6-dihydro-2H-oxazolo[4,5-c]carbazol-2-one, were readily prepared from the product, demonstrating synthetic utility of this method.

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N-Bromosuccinimide (NBS)-Catalyzed C–H Bond Functionalization: An Annulation of Alkynes with Electron Withdrawing Group (EWG)-Substituted Acetyl Indoles for the Synthesis of Carbazoles

Cited by 39 publications

References 92 publications

Recent Developments in the Cyclization of Alkynes and Nitrogen Compounds for the Synthesis of Indole Derivatives

Recent Developments in the Cyclization of Alkynes and Nitrogen Compounds for the Synthesis of Indole Derivatives

Synthesis, Molecular Docking, and Biofilm Formation Inhibitory Activity of Bis(Indolyl)Pyridines Analogues of the Marine Alkaloid Nortopsentin

Synthesis of 4-Hydroxycarbazole Derivatives by Benzannulation of 3-Nitroindoles with Alkylidene Azlactones

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