- New syntheses of the marine alkaloids eudistomins D and U
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Short and convergent syntheses of eudistomins U and D are reported. The approach is based on a convergent methodology which involves such reactions as metalation and heteroring cross-coupling.
- Rocca,Rocca, Patrick,Marsais,Marsais, Francis,Godard,Godard, Alain,Queguiner,Queguiner, Guy,Adams,Adams, Luqman,Alo,Alo, Babajide
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- Access to 1-indolyltetrahydro-β-carbolines: via metal-free cross-dehydrogenative coupling: The total synthesis of eudistomin U, isoeudistomin U and 19-bromoisoeudistomin U
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A highly selective and captivating metal-free cross-dehydrogenative coupling for the cross-coupling of two reactive nucleophiles such as tetrahydro-β-carboline and indoles is developed. A series of 1-indolyltetrahydro-β-carboline derivatives were synthesized in excellent to moderate yields. Temperature, time and concentration control resulted in mono indolylation selectively. Moreover, the total synthesis of eudistomin U and isoeudistomin U and the first total synthesis of 19-bromoisoeudistomin U were accomplished.
- Ranjani, Ganapathy,Nagarajan, Rajagopal
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- Manipulation of Water for Diversified Functionalization of Tetrahydro-β-carbolines (THβCs) with Indoles
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Water plays a crucial role in organic synthesis. However, diversified functionalization manipulated by water is still rare and remains unexplored. Herein, we report the first water-manipulated protocol to achieve the diversified functionalization of tetrahydro-β-carbolines (THβCs) in an open flask at room temperature that exhibit a broad functional-group tolerance. More water leads to monoarylation, while less water leads to diarylation. Further one-step transformation afforded oxidized bis(indolyl)methanes, eudistomin U, and the related derivatives in satisfactory yields.
- Xu, Dekang,Ye, Fu,Ye, Jinxiang,Gao, Yu,Chen, Haijun
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- An iminophosphorane-mediated efficient synthesis of the alkaloid eudistomin U of marine origin
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The first synthesis of the alkaloid eudistomin U, by a four-step sequence is described. The key step, formation of the β-carboline ring, involves a tandem aza Wittig/electrocyclic ring closure process.
- Molina, Pedro,Fresneda, Pilar M.,Garcia-Zafra, Sagrario
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- Efficient synthesis of eudistomin U and evaluation of its cytotoxicity
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Eudistomin U is a member of a subclass of naturally occurring indole alkaloids known as β-carbolines. These molecules are reported to have diverse biological activity and high binding affinity to DNA, which make them attractive targets for total synthesis
- Roggero, Chad M.,Giulietti, Jennifer M.,Mulcahy, Seann P.
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- Visible light mediated selective oxidation of alcohols and oxidative dehydrogenation of N-heterocycles using scalable and reusable La-doped NiWO4nanoparticles
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Visible light-mediated selective and efficient oxidation of various primary/secondary benzyl alcohols to aldehydes/ketones and oxidative dehydrogenation (ODH) of partially saturated heterocycles using a scalable and reusable heterogeneous photoredox catalyst in aqueous medium are described. A systematic study led to a selective synthesis of aldehydes under an argon atmosphere while the ODH of partially saturated heterocycles under an oxygen atmosphere resulted in very good to excellent yields. The methodology is atom economical and exhibits excellent tolerance towards various functional groups, and broad substrate scope. Furthermore, a one-pot procedure was developed for the sequential oxidation of benzyl alcohols and heteroaryl carbinols followed by the Pictet-Spengler cyclization and then aromatization to obtain the β-carbolines in high isolated yields. This methodology was found to be suitable for scale up and reusability. To the best of our knowledge, this is the first report on the oxidation of structurally diverse aryl carbinols and ODH of partially saturated N-heterocycles using a recyclable and heterogeneous photoredox catalyst under environmentally friendly conditions.
- Abinaya, R.,Balasubramaniam, K. K.,Baskar, B.,Divya, P.,Mani Rahulan, K.,Rahman, Abdul,Sridhar, R.,Srinath, S.
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p. 5990 - 6007
(2021/08/24)
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- Application of metal free aromatization to total synthesis of perlolyrin, flazin, eudistomin U and harmane
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Application of our recently reported metal free reaction conditions to the total synthesis of the four different and selective biologically interesting β-carboline natural products is reported. Using this simple methodology, flazin, perlolyrine, eudistomin U and harmane containing heteroaryl and alkyl substituents at C1 position were synthesized in good yields. (Figure presented.).
- Santhanam, Srinath,Ramu, Abinaya,Baburaj, Baskar,Kalpatu Kuppusamy, Balasubramanian
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p. 2121 - 2127
(2020/03/04)
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- Reusable, homogeneous water soluble photoredox catalyzed oxidative dehydrogenation of N-heterocycles in a biphasic system: Application to the synthesis of biologically active natural products
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Herein, a simple and efficient method for the oxidative dehydrogenation (ODH) of tetrahydro-β-carbolines, indolines and tetrahydro-(iso)quinolines is described using a reusable, homogeneous cobalt-phthalocyanine photoredox catalyst in a biphasic medium. A biphasic system offers an advantage of easy separation of the product and an efficient reusability of the homogeneous photoredox catalyst. Also, the current system significantly helps to overcome the solubility issue of the substrate and catalyst at room temperature. Its potential applications to organic transformations are demonstrated by the synthesis of various biologically active N-heterocycles such as indoles, (iso)quinolines and β-carbolines and natural products such as eudistomin U, norharmane, and harmane and precursors to perlolyrine and flazin. Without isolation and purification, the catalyst solution can be reused up to 5 times with almost comparable reactivity. Furthermore, the efficiency of the reaction was demonstrated on a gram scale. To the best of our knowledge, this is the first report on ODH reactions using a non noble, reusable and homogeneous cobalt photoredox catalyst under environmentally friendly conditions.
- Abinaya, R.,Baskar, B.,Mariappan, M.,Prasanth, Arun,Sridhar, R.,Srinath, S.
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p. 2575 - 2587
(2020/05/13)
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- Organic base-promoted efficient dehydrogenative/decarboxylative aromatization of tetrahydro-β-carbolines into β-carbolines under air
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Organic base DBN has been identified as an efficient reagent for promoting the dehydrogenative/decarboxylative aromatization of tetrahydro-β-carbolines under air atmosphere, to access the corresponding β-carbolines in moderate to good yields. The utility of this protocol for the gram-scale synthesis of β-carboline alkaloids eudistomin U (7) and harmane (10) has also been demonstrated.
- Zhao, Ziquan,Sun, Yan,Wang, Lilin,Chen, Xuan,Sun, Yanpei,Lin, Long,Tang, Yulin,Li, Fei,Chen, Dongyin
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supporting information
p. 800 - 804
(2019/02/16)
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- Iodine-catalyzed chemoselective dehydrogenation and aromatization of tetrahydro-β-carbolines: A short synthesis of Kumujian-C, Eudistomin-U, Norharmane, Harmane Harmalan and Isoeudistomine-M
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Temperature controlled chemoselective dehydrogenation and aromatization of tetrahydro-β-carbolines, using molecular I2 and H2O2, in DMSO solvent affords a practical access to a series of corresponding 3,4-dihydro-β-carbolines and β-carbolines respectively. This method has been successfully employed in the short synthesis of Kumujian-C, Eudistomin-U, Norharmane Harmane Harmalan and Isoeudistomin-M.
- Gaikwad, Sunil,Kamble, Dayanand,Lokhande, Pradeep
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supporting information
p. 2387 - 2392
(2018/05/24)
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- Synthesis of tetrahydro-β-carbolines, β-carbolines, and natural products, (±)-harmicine, eudistomin U and canthine by reductive Pictet Spengler cyclization
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Reductive Pictet Spengler cyclization was used for the synthesis of naturally occurring β-carbolines, eudistomin U, and canthine. Other biologically important β-carbolines as well as tetrahydro-β-carboline, such as (±)-harmicine were also synthesized usin
- Pakhare, Deepali S.,Kusurkar, Radhika S.
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p. 6012 - 6015
(2015/10/28)
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- PhI(OAc)2-mediated one-pot oxidative decarboxylation and aromatization of tetrahydro-β-carbolines: Synthesis of norharmane, harmane, eudistomin U and eudistomin i
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Iodobenzene diacetate was employed as a mild and efficient reagent for one-pot oxidative decarboxylation of tetrahydro-β-carboline acids and dehydrogenation of tetrahydro-β-carbolines to access the corresponding aromatic β-carbolines. To the best of our knowledge this is the first synthesis of β-carbolines via a one-pot oxidative decarboxylation at ambient temperature. The utility of this protocol has been demonstrated in the synthesis of β-carboline alkaloids norharmane (2o), harmane (2p), eudistomin U (9) and eudistomin I (12).
- Kamal, Ahmed,Tangella, Yellaiah,Manasa, Kesari Lakshmi,Sathish, Manda,Srinivasulu, Vunnam,Chetna, Jadala,Alarifi, Abdullah
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p. 8652 - 8662
(2015/08/24)
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- An efficient one-pot decarboxylative aromatization of tetrahydro-β-carbolines by using N-chlorosuccinimide: total synthesis of norharmane, harmane and eudistomins
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A facile method for the synthesis of a variety of β-carbolines and their natural products such as norharmane (2a), harmane (2b), eudistomins I, N, T, and U (6, 7, 9 and 10, respectively) has been successfully developed via a decorboxylative aromatization tool by employing N-chlorosuccinimide (NCS) as a mild and efficient reagent. Gratifyingly, this reagent system proceeds in a one-pot manner and converted all the tetrahydro-β-carboline acids into their corresponding decorboxylative aromatic products with good to excellent yields. Additionally, this system works well in the case of tetrahydro-β-carboline esters to produce their aromatic partners in high yields.
- Kamal, Ahmed,Sathish, Manda,Prasanthi,Chetna, Jadala,Tangella, Yellaiah,Srinivasulu, Vunnam,Shankaraiah, Nagula,Alarifi, Abdullah
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p. 90121 - 90126
(2015/11/10)
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- Efficient synthesis of eudistomin U and evaluation of its cytotoxicity
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Eudistomin U is a member of a subclass of naturally occurring indole alkaloids known as β-carbolines. These molecules are reported to have diverse biological activity and high binding affinity to DNA, which make them attractive targets for total synthesis
- Roggero, Chad M.,Giulietti, Jennifer M.,Mulcahy, Seann P.
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supporting information
p. 3549 - 3551
(2015/02/19)
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- Synthesis of 1-indolyl substituted β-carboline natural products and discovery of antimalarial and cytotoxic activities
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A series of 1-indolyl substituted β-carbolines including the natural products hyrtiosulawesine, pityriacitrin and pityriacitrin B were prepared via Pictet-Spengler condensation - oxidation strategy from the corresponding indolyl-acetaldehydes and substituted tryptamines. Efforts to prepare the C-1 methylene-linked β-carboline analogues for structure-activity relationship studies were unsuccessful. Biological evaluation revealed two analogues (5 and 41) to exhibit weak inhibition of phospholipase A2 (IC50 171 and 131 μM, respectively), two to act as antioxidants (3 and 43), and 12 analogues with activity towards a chloroquine-resistant strain (FcB1) of Plasmodium falciparum (IC50 1.0-23 μM). Testing against a panel of 60 human tumour cell lines revealed a general lack of cytotoxic effect for most of the compounds with the exception of β-carboline 42 exhibiting modest antileukaemic activity towards the HL-60(TB) cell line (LC50 4.2 μM). In addition, two novel structures (30 and 32) resulting from aldol condensation followed by Pictet-Spengler cyclisation displayed cytotoxicity with pronounced subpanel specificities towards colon cancer (COLO 205 and HCC-2998) cell lines.
- Liew, Lydia P.P.,Fleming, Jessica M.,Longeon, Arlette,Mouray, Elisabeth,Florent, Isabelle,Bourguet-Kondracki, Marie-Lise,Copp, Brent R.
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p. 4910 - 4920
(2014/07/07)
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- Oxidative C-H/C-H coupling of azine and indole/pyrrole nuclei: Palladium catalysis and synthesis of eudistomin U
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We have developed a palladium-catalyzed C-H/C-H coupling reaction of indoles or pyrroles with azine N-oxides. The reaction proceeds selectively at the C3 position of indoles/pyrroles and the C2 position of azine N-oxides. Furthermore, we have accomplished
- Yamaguchi, Atsushi D.,Mandal, Debashis,Yamaguchi, Junichiro,Itami, Kenichiro
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p. 555 - 557
(2011/07/08)
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- Synthesis of β- And γ-carbolines via ruthenium and rhodium catalysed [2+2+2] cycloadditions of yne-ynamides with methylcyanoformate
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A flexible approach towards substituted β- and γ-carbolines based on transition metal catalysed [2+2+2] cycloaddition reactions between functionalised yne-ynamides and methylcyanoformate is described. The versatility of this new reaction sequence is demon
- Nissen, Felix,Richard, Vincent,Alayrac, Carole,Witulski, Bernhard
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p. 6656 - 6658
(2011/06/27)
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- Room-temperature aromatization of tetrahydro-β-carbolines by 2-iodoxybenzoic acid: Utility in a total synthesis of eudistomin U
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2-Iodoxybenzoic acid is a convenient reagent for the dehydrogenation of tetrahydro-β-carbolines to their aromatic forms under mild conditions. The utility of the method was demonstrated in a total synthesis of the marine indole alkaloid eudistomin U.
- Panarese, Joseph D.,Waters, Stephen P.
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supporting information; experimental part
p. 4086 - 4089
(2010/11/16)
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