- Short synthesis of carbazole alkaloids: Ekeberginine, murrayaquinone A, and glycozoline
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Three differently substituted, naturally occurring, biologically active carbazole derivatives (viz. ekeberginine, murrayaquinone A, and glycozoline) were synthesized in good yield using short and simple routes. The prenyl group was selectively introduced at the C4 position using a Stille coupling reaction in the synthesis of ekeberginine. Murrayaquinone A was synthesized using Raney nickel–mediated desulfurization of dithiane as a key step. Synthesis of glycozoline was achieved in two steps from 3-methyl carbazole via an intermediate 3-bromo-6-methyl carbazole.
- Momin, Aadil A.,Urmode, Tukaram D.,Bhosale, Shrikar M.,Kusurkar, Radhika S.
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- Synthesis of Carbazoles by a Diverted Bischler-Napieralski Cascade Reaction
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An unforeseen twist in a seemingly trivial Bischler-Napieralski reaction led to the selective formation of an unexpected carbazole product. The reaction proved to be general, providing access to a range of diversely substituted carbazoles from readily available substrates. Judicious variation of substituents revealed a complex cascade mechanism comprising no less than 10 elementary steps, that could be diverted in multiple ways toward various other carbazole derivatives.
- Faltracco, Matteo,Ortega-Rosales, Said,Janssen, Elwin,Cioc, Rǎzvan C.,Vande Velde, Christophe M. L.,Ruijter, Eelco
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p. 3100 - 3104
(2021/05/05)
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- A one-pot "back-to-front" approach for the synthesis of benzene ring substituted indoles using allylboronic acids
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Synthesis of only benzene ring functionalized indoles and poly-substituted carbazoles is reported via a one-pot triple cascade benzannulation protocol. Usage of differently substituted and readily accessible allylboronic acids as a 3-carbon annulating partner enables diverse aliphatic and aromatic substitution patterns, which is still a daunting task. This scalable synthetic protocol tolerates broad scope, thus enabling further downstream modifications. As an application, carbazole based natural products glycozoline and glycozolinol were synthesized. This journal is
- Karan, Ganesh,Sahu, Samrat,Maji, Modhu Sudan
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supporting information
p. 5274 - 5277
(2021/06/06)
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- Scalable Electrochemical Transition-Metal-Free Dehydrogenative Cross-Coupling Amination Enabled Alkaloid Clausines Synthesis
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Reported herein is an environmentally benign electrochemical C?H bond dehydrogenative amination protocol for the construction of privileged carbazole moiety with broad generality. Preliminary mechanistic investigations implied a radical reaction pathway.
- Zhang, Pan,Li, Baoying,Niu, Liwei,Wang, Ling,Zhang, Guofeng,Jia, Xiaofei,Zhang, Guoying,Liu, Siyuan,Ma, Li,Gao, Wei,Qin, Dawei,Chen, Jianbin
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supporting information
p. 2342 - 2347
(2020/05/05)
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- Total synthesis of carbazole alkaloids
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A Suzuki-Miyaura cross coupling, followed by triphenylphosphine mediated Cadogan reductive cyclization sequence provided efficient access to a series of carbazole alkaloids. In the present work, this approach was applied to the total synthesis of mukonine, clauszoline K, koenoline, murrayanine, murrayafoline A, mukoeic acid, glycoborine, glycozolicine, mukolidine, mukoline, glycozoline, 3-methoxy-9H-carbazole-1-carboxylic acid methyl ester, (3-methoxy-9H-carbazol-1-yl)-methanol, 3-methoxy-9H-carbazole-1-carbaldehyde, 3-methoxy-9H-carbazole-1-carboxylic acid, 2-methyl-9H-carbazole and nonsteroidal anti-inflammatory drug (NSAID) carprofen and its derivatives.
- Bhatthula, Bharath kumar goud,Kanchani, Janardhan reddy,Arava, Veera reddy,Subha
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p. 874 - 887
(2019/01/11)
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- Substituent-Guided Palladium-Ene Reaction for the Synthesis of Carbazoles and Cyclopenta[ b]indoles
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An efficient palladium-catalyzed intramolecular Trost-Oppolzer type Alder-ene strategy was developed for the synthesis of carbazoles and cyclopenta[b]indoles from easily accessible(3-allyl-1H-indol-2-yl)methyl acetates. This strategy was extended for the synthesis of naphthalenes and dibenzobenzofurans as well. In addition, a short synthesis of antibacterial and antifungal natural product glycozoline and its analogues was also achieved.
- Yadav, Sonu,Hazra, Raju,Singh, Animesh,Ramasastry
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- Substituent-Guided Palladium-Ene Reaction for the Synthesis of Carbazoles and Cyclopenta[b]indoles
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An efficient palladium-catalyzed intramolecular Trost-Oppolzer type Alder-ene strategy was developed for the synthesis of carbazoles and cyclopenta[b]indoles from easily accessible(3-allyl-1H-indol-2-yl)methyl acetates. This strategy was extended for the synthesis of naphthalenes and dibenzobenzofurans as well. In addition, a short synthesis of antibacterial and antifungal natural product glycozoline and its analogues was also achieved.
- Yadav, Sonu,Hazra, Raju,Singh, Animesh,Ramasastry
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p. 2983 - 2987
(2019/05/10)
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- "on Water" Promoted Ullmann-Type C-N Bond-Forming Reactions: Application to Carbazole Alkaloids by Selective N-Arylation of Aminophenols
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The Ullmann-type cross coupling of a variety of aromatic, aliphatic amines with aryl halides is reported using a CuI-based catalytic system in combination with an easily accessible prolinamide ligand in aqueous media. The method is mild and tolerant to air, moisture, and a wide range of functional groups, providing a novel way to access a variety of aminated products. Secondary amines like heteroaromatic amines and nucleobases have also been used, affording the corresponding coupling products in good to excellent yields. Moreover, this method has been employed for chemoselective C-N arylation of aminophenols and further utilized for the synthesis of carbazole natural products, avoiding the protection and deprotection steps.
- Chakraborti, Gargi,Paladhi, Sushovan,Mandal, Tirtha,Dash, Jyotirmayee
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p. 7347 - 7359
(2018/07/29)
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- Divergent and Orthogonal Approach to Carbazoles and Pyridoindoles from Oxindoles via Indole Intermediates
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The previously unexplored Grignard addition to oxindoles provides a regiospecific approach to 2- and 2,3-disubstituted indole derivatives in high yields via a one-pot aromatization driven dehydration pathway. This method allows a convenient preparation of diallyl indoles that are used as ring-closing metathesis (RCM) precursors for the orthogonal synthesis of pyrido[1,2-a]indoles and carbazoles. The synthetic utility of this method is illustrated by the synthesis of a microtubulin inhibitor and naturally occurring carbazole alkaloids.
- Mandal, Tirtha,Chakraborti, Gargi,Karmakar, Shilpi,Dash, Jyotirmayee
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p. 4759 - 4763
(2018/08/24)
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- Copper(II) catalyzed aromatization of tetrahydrocarbazole: An unprecedented protocol and its utility towards the synthesis of carbazole alkaloids
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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.
- Dalvi, Bhakti A.,Lokhande, Pradeep D.
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p. 2145 - 2149
(2018/05/08)
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- Denitrogenative Suzuki and carbonylative Suzuki coupling reactions of benzotriazoles with boronic acids
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Unprecedented palladium-catalyzed denitrogenative Suzuki and carbonylative Suzuki coupling reactions of benzotriazoles with boronic acids have been realized, which afforded structurally diverse ortho-amino-substituted biaryl and biaryl ketone derivatives. The key to this success is due to the development of a rationally designed strategy to achieve the ring opening of benzotriazoles with a synergistic activating-stabilizing effect, which enables the in situ generation of the corresponding ortho-amino-arenediazonium species. The present work opens up a new avenue to utilize benzotriazoles as synthetic equivalents of ortho-amino-arenediazoniums, which otherwise could not be directly accessed by existing synthetic methods.
- Wang, Yuanhao,Wu, Yunfei,Li, Yuanhe,Tang, Yefeng
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p. 3852 - 3857
(2017/07/11)
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- A Palladium-Catalyzed Ullmann Cross-Coupling/Reductive Cyclization Route to the Carbazole Natural Products 3-Methyl-9H-carbazole, Glycoborine, Glycozoline, Clauszoline K, Mukonine, and Karapinchamine A
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The title natural products 2-7 have been prepared by reductive cyclization of the relevant 2-arylcyclohex-2-en-1-one (e.g. 20) to the corresponding tetrahydrocarbazole and dehydrogenation (aromatization) of this to give the target carbazole (e.g. 4). Compounds such as 20 were prepared using a palladium-catalyzed Ullmann cross-coupling reaction between the appropriate 2-iodocyclohex-2-en-1-one and o-halonitrobenzene.
- Yan, Qiao,Gin, Emma,Wasinska-Kalwa, Malgorzata,Banwell, Martin G.,Carr, Paul D.
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p. 4148 - 4159
(2017/04/27)
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- One-pot synthesis of carbazoles via tandem C-C cross-coupling and reductive amination
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We have developed a highly efficient synthetic route to carbazoles that employs sequential C-C/C-N bond formation via Suzuki cross-coupling and Cadogan cyclization using commercially available or easily preparable starting materials. The developed method is compatible with electron neutral, rich or deficient substrates. The synthetic utility of this method was demonstrated by the concise syntheses of four natural products (glycozoline, glycozolicine, glycozolidine and clausenalene).
- Goo, Deuk-Young,Woo, Sang Kook
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supporting information
p. 122 - 130
(2015/12/30)
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- A one-pot direct iodination of the Fischer-Borsche ring using molecular iodine and its utility in the synthesis of 6-oxygenated carbazole alkaloids
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An efficient regioselective iodination of the Fischer-Borsche ring has been achieved using molecular iodine, in a one-pot synthesis. The acid-, metal-, and oxidant-free conditions of the present method are highly convenient and practical. Furthermore, the one-pot direct iodination process is extended to the concise synthesis of glycozoline, 3-formyl-6-methoxy-carbazole, and 6-methoxy-carbazole-3-methylcarboxylate natural alkaloids. This method has been proven to be tolerant to a broad range of functional groups, with good to excellent yields.
- Naykode, Mahavir S.,Humne, Vivek T.,Lokhande, Pradeep D.
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p. 2392 - 2396
(2015/05/04)
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- Iodine-catalyzed aromatization of tetrahydrocarbazoles and its utility in the synthesis of glycozoline and murrayafoline A: A combined experimental and computational investigation
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A new protocol for the aromatization of tetrahydrocarbazoles has been achieved using a catalytic amount of iodine, giving high yields. The role of iodine in the aromatization has been explained by DFT, and its wide scope is extended to the total synthesis of glycozoline and murrayafoline A. This method has proven to be tolerant of a broad range of functional groups. This journal is the Partner Organisations 2014.
- Humne, Vivek,Dangat, Yuvraj,Vanka, Kumar,Lokhande, Pradeep
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supporting information
p. 4832 - 4836
(2014/07/07)
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- C-N bond formation via Cu-catalyzed cross-coupling with boronic acids leading to methyl carbazole-3-carboxylate: Synthesis of carbazole alkaloids
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Copper promoted N-arylation of methyl 4-amino-3-iodobenzoate with boronic acids followed by Pd-catalyzed intramolecular C-H arylation provides an efficient route to methyl carbazole-3-carboxylate derivatives. This methodology was implemented in the synthe
- Rasheed, Sk.,Rao, D. Nageswar,Reddy, K. Ranjith,Aravinda,Vishwakarma, Ram A.,Das, Parthasarathi
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p. 4960 - 4969
(2014/01/23)
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- A tandem reduction-oxidation protocol for the conversion of 1-keto-1,2,3,4-tetrahydrocarbazoles to carbazoles via tosylhydrazones through microwave assistance: Efficient synthesis of glycozoline, clausenalene, glycozolicine, and deoxycarbazomycin B and the total synthesis of murrayafoline A
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A novel and efficient methodology for the synthesis of carbazoles from 1-keto-1,2,3,4-tetrahydrocarbazoles via the corresponding tosylsulfonhydrazones by a one-pot tandem reduction-oxidation protocol using a combination of NaBH4 and Pd-C on MgSO4·7H2O, a solid support, under microwave is developed. The reaction is successfully extended toward the synthesis of several naturally occurring carbazole alkaloids, namely 3-methylcarbazole, glycozoline, clausenalene, glycozolicine, murrayafoline A, and deoxycarbazomycin B, a carbazole derivative that is known to have a promising antimicrobial activity.
- Chakraborty, Suchandra,Chattopadhyay, Gautam,Saha, Chandan
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- Transition-metal-free direct arylation of anilines
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Aryne arylation: A new method of direct arylation is reported for aniline substrates. The reaction uses benzyne to synthesize a variety of aminobiaryls under mild conditions (see scheme), requiring no stoichiometric metalation or transition-metal catalysis. An ene mechanism is implicated, and conveys excellent functional group tolerance relative to metal-mediated processes. Copyright
- Pirali, Tracey,Zhang, Fengzhi,Miller, Anna H.,Head, Jenna L.,McAusland, Donald,Greaney, Michael F.
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p. 1006 - 1009
(2012/02/16)
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- Pd-catalyzed intramolecular oxidative C-H amination: Synthesis of carbazoles
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A Pd-catalyzed oxidative C-H amination of N-Ts-2-arylanilines under ambient temperature using Oxone as an inexpensive, safe, and easy-to-handle oxidant has been developed. This process represents a green and practical method for the facile construction of carbazoles with a broad substrate scope and wide functional group tolerance.
- Youn, So Won,Bihn, Joon Hyung,Kim, Byung Seok
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supporting information; experimental part
p. 3738 - 3741
(2011/09/13)
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- Solvent-free synthesis of δ-carbolines/carbazoles from 3-nitro-2-phenylpyridines/2-nitrobiphenyl derivatives using DPPE as a reducing agent
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A green and efficient preparation of functionalized δ-carbolines/ carbazoles via reductive ring closure by 1,2-bis(dipenylphosphino)ethane under solvent-free conditions is described. The starting materials 3-nitro-2-phenylpyridines/2-nitrobiphenyl derivatives are readily prepared through Suzuki-Miyaura cross-coupling reaction from commercially available compounds. And the polar by-product ethane-1,2-diylbis(diphenylphosphine oxide) is easily removed from the relatively polar reaction mixture. Various substituted δ-carbolines/carbazoles are obtained in acceptable yields. It is particularly worth mentioning that substrates with electron-withdrawing groups (EWG) also give the desired products in good yield.
- Peng, Haixia,Chen, Xuxing,Chen, Yanhong,He, Qian,Xie, Yuyuan,Yang, Chunhao
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p. 5725 - 5731
(2011/08/09)
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- A synthetic approach to carbazoles using electrochemically generated hypervalent iodine oxidant
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Carbazoles were successfully synthesized by oxidative cyclization of the corresponding diaryl derivatives using electrochemically generated hypervalent iodine oxidant. Electron-withdrawing nitro and donating methoxy groups at the para position of the acetamide group interfered with cyclization. Glycozoline (8) was successfully synthesized in five steps with 50% overall yield.
- Kajiyama, Daichi,Inoue, Keisuke,Ishikawa, Yuichi,Nishiyama, Shigeru
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p. 9779 - 9784
(2011/03/17)
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- Transition metals in organic synthesis - Part 83#: Synthesis and pharmacological potential of carbazoles
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A series of carbazole derivatives with promising pharmacological properties has been prepared using either an iron-mediated or a palladium-catalyzed synthetic approach. The carbazole alkaloids carbazoquinocin C, carbazomadurin A and B, epocarbazolin A and
- Choi, Taylor A.,Czerwonka, Regina,Forke, Ronny,Jaeger, Anne,Knoell, Jan,Krahl, Micha P.,Krause, Tilo,Reddy, Kethiri R.,Franzblau, Scott G.,Knoelker, Hans-Joachim
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p. 374 - 385
(2008/12/23)
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- Transition metals in organic synthesis, part 82.1 First total synthesis of methyl 6-methoxycarbazole-3-carboxylate, glycomaurrol, the anti-TB active micromeline, and the furo[2,3-c]carbazole alkaloid eustifoline-D
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The palladium(0)-catalyzed animation followed by palladium(II)-catalyzed oxidative cyclization of the resulting diarylamine provides a short route to a series of 6-oxygenated carbazole alkaloids: glycozoline, 3-formyl-6- methoxycarbazole, methyl 6-methoxy
- Forke, Ronny,Krahl, Micha P.,Krause, Tilo,Schlechtingen, Georg,Kn?lker, Hans-Joachim
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p. 268 - 272
(2007/10/03)
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- Two new carbazole alkaloids from Murraya koenigii
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Two new alkaloids, 1-formyl-3-methoxy-6-methylcarbazole 1 and 6,7-dimethoxy-1-hydroxy-3-methylcarbazole 2, have been isolated from the leaves of Murraya koenigii. Both the compounds have been identified by spectral as well as chemical evidences, and their structures confirmed by synthesis. Compound 2 is found to be active against Gram-positive and Gram-negative bacteria and fungi.
- Chowdhury,Jha,Bhattacharyya,Mukherjee
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p. 490 - 494
(2007/10/03)
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- One-step Conversion of Oxotetrahydrocarbazole into Carbazole
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Oxotetrahydrocarbazoles (Ia-e) when heated with a 1:1 mixture of KOH + NaOH furnish the corresponding carbazoles (IIa-e) in good yields (ca. 80percent).The method appears to be of general applicability.
- Bhattacharyya, P.,Jash, S. S.
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- Structure and Synthesis of Glycozolinol, a New Carbazole Alkaloid from Glycosmis pentaphylla (Retz) DC.
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Glycozolinol, a new carbazole alkaloid isolated from Glycosmis pentaphylla (Retz) DC. has been formulated as 6-hydroxy-3-methylcarbazole (I) based on physical data, chemical reactions and spectral evidences.The structure (I) has been confirmed by synthesis.
- Bhattacharyya, P.,Sarkar, T.,Chakraborty, A.,Chowdhury, B. K.
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- GLYCOZOLININE, A CARBAZOLE DERIVATIVE FROM GLYCOSMIS PENTAPHYLLA
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Key Word Index - Glycosmis pentaphylla; Rutaceae; seeds; alkaloids; glycozolinine; carbazole. A new carbazole derivative, glycozolinine, was isolated from the seeds of Glycosmis pentaphylla.From physical and chemical evidence its structure is 6-hydroxy-3-methylcarbazole.
- Mukherjee, S.,Mukherjee, M.,Ganguly, S. N.
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p. 1064 - 1065
(2007/10/02)
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