- Microwave assisted Pictet-Spengler and Bischler-Napieralski reactions
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Pictet-Spengler and Bischler-Napieralski reaction products have been prepared-using microwave irradiation on silicagel support under solvent free condition. Microwave assisted reactions have resulted in better yields of the desired products than prepared
- Pal, Bikash,Jaisankar, Parasuraman,Giri, Venkatachalam S.
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Read Online
- Asymmetric Biocatalytic Synthesis of 1-Aryltetrahydro-β-carbolines Enabled by “Substrate Walking”
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Stereoselective catalysts for the Pictet–Spengler reaction of tryptamines and aldehydes may allow a simple and fast approach to chiral 1-substituted tetrahydro-β-carbolines. Although biocatalysts have previously been employed for the Pictet–Spengler react
- Eger, Elisabeth,Iding, Hans,Kroutil, Wolfgang,Kuhn, Bernd,Schrittwieser, Joerg H.,Wetzl, Dennis
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p. 16281 - 16285
(2020/11/30)
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- Selective construction of alkaloid scaffolds by alcohol-based direct and mild aerobic oxidative Pictet-Spengler reactions
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Employing TBN/TEMPO as the catalysts and oxygen as the oxidant, the biologically and pharmaceutically significant tetrahydro-β-carboline and β-carboline alkaloid scaffolds that used to be obtained by multi-step processes can now be selectively obtained in only one-stepviadirect aerobic oxidative Pictet-Spengler reactions of tryptamines with alcohols under mild conditions, with water generated as the byproduct. In this reaction, TBN/TEMPO was interestingly found to be able to facilitate the cyclization step of the whole reaction. This method tolerates a variety ofC- andN-substituted tryptamines, and both the more reactive benzylic and allylic alcohols and the less reactive aliphatic alcohols. This method can also be extended to dihydro-β-carboline synthesis and applied to the more available and more economical tryptophan for β-carboline synthesis, revealing its broad substrate scope and potential in synthetic applications.
- Han, Feng,Li, Huan,Liu, Haicheng,Liu, Jianping,Xu, Qing
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supporting information
p. 7079 - 7085
(2020/10/02)
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- Metal free one pot synthesis of Β-carbolines via a domino Pictet-Spengler reaction and aromatization
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A convenient and efficient metal free, atom economical flexible synthesis of β-carbolines involving a domino Pictet-Spengler reaction and aromatization in oxygen atmosphere in N-methyl-2-pyrollidone (NMP) is described. Variety of aryl, heteroaryl and aliphatic aldehydes were found to be good substrates for this methodology. Several β-carbolines (6a-6t) and β-carboline methyl esters (7a-7e) were synthesized using this methodology.The same reaction carried out in argon atmosphere in the presence of catalytic amount of acid in NMP furnished, tetrahydro-β-carbolines (4a-4g).
- Ramu,Srinath,kumar, A. Aswin,Baskar,Ilango,Balasubramanian
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- Iodine-Catalyzed Metal-Free Oxidative Ring Opening of 1-Aryltetrahydro-β-carbolines: Facile Synthesis of C-2 Aroyl and Aryl Methanimino Indole Derivatives
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Indole derivatives bearing C-2 substituents have garnered a lot of attention due to their diverse biological activities. Various methods forthe synthesis of these compounds have been reported. Inspired by the hydrolysis of imines, an oxidative ring-opening reaction of 1-aryltetrahydro-β-carbolines with catalytic iodine in aqueous hydrogen peroxide, and also in the presence of appropriate amines, is described for the generation of 2-aroyl and arylmethanimine indole derivatives. The reaction proceeds under mild reaction conditions with ethanol as the solvent or under solvent-free conditions, respectively. This metal-free strategy facilitates the formation of the desired substituted C-2 indoles in moderate to excellent yields. The utility of this reaction is demonstrated by a facile multigram-scale synthesis of Luzindole, a selective melatonin receptor antagonist and an investigational drug against depression and disruption of the circadian rhythm.
- Chauhan, Jyoti,Luthra, Tania,Sen, Subhabrata
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supporting information
p. 4776 - 4786
(2018/09/06)
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- Cu-catalyzed mild and efficient oxidation of THβCs using air: Application in practical total syntheses of perlolyrine and flazin
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A mild, efficient and environmentally benign method for synthesis of aromatic β-carbolines via Cu(ii)-catalyzed oxidation of 1,2,3,4-tetrahydro-β-carbolines (THβCs) was developed, in which air (O2) was used as the clean oxidant. This method has advantages such as environmentally friendliness, mildness, very good tolerance of functional groups, high yielding and easy experiment operation. In addition, this new methodology was successfully applied in the efficient and practical total syntheses of β-carboline alkaloids perlolyrine and flazin.
- Zheng, Bo,Trieu, Tien Ha,Meng, Tian-Zhuo,Lu, Xia,Dong, Jing,Zhang, Qiang,Shi, Xiao-Xin
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p. 6834 - 6839
(2018/02/23)
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- Design, synthesis and biological evaluation of a novel library of antimitotic C2-aroyl/arylimino tryptamine derivatives that are also potent inhibitors of indoleamine-2, 3-dioxygenase (IDO)
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A novel library of C2-substituted tryptamines (based on diverse C2-aroyl/arylimino indoles and indole-diketopiperazine hybrids) possessing antimitotic properties were designed, synthesized and screened for their inhibitory activity against tubulin polymerization, and against proliferation of A549 lung cancer, HeLa cervical cancer, MCF7 breast cancer and HePG2 liver cancer cell lines. The design of molecules were inspired from known antimitotic compounds and natural products. The molecular docking of the designed compounds indicated that they bind to the colchicin binding site of tubulin. They were synthesized by a unique iodine catalysed oxidative ring opening reaction of 1-aryltetrahydro-β-carbolines. Among the compounds synthesized quite a few compounds induced cytotoxicity on the cancer cells by disrupting the tubulin polymerization. They were found to be non-toxic for healthy cells. Immuno Fluorescence study for the most active molecules (between ~6 μM concentration) against A549 and HeLa cells demonstrated complete disruption and shrinkage of the microtubule structures. These compounds also inhibited indoleamine-2, 3-dioxygenase with low micromolar IC50.
- Chauhan, Jyoti,Dasgupta, Moumita,Luthra, Tania,Awasthi, Akanksha,Tripathy, Sayantan,Banerjee, Anindyajit,Paul, Santanu,Nag, Debasish,Chakrabarti, Saikat,Chakrabarti, Gopal,Sen, Subhabrata
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p. 249 - 265
(2018/09/12)
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- Ultrasound Assisted Pictet-Spengler Synthesis of Tetrahydro-β-Carboline Derivatives
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The synthesis of twelve tetrahydro-β-carboline derivatives 3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h, 3i, 3j, 3k, 3l prepared via the Pictet-Spengler reaction is described. The reaction of tryptamine and a variety of arylaldehydes were carried out under ultrasonic irradiation and trifluoracetic acid catalysis at room temperature. These tetrahydro-β-carbolines have been synthesized in higher yields and shorter reaction times compared to the conventional method. Moreover, the reaction proceeded successfully even employing arylaldehydes with electron-donating or electron-attracting substituents which did not react under conventional method.
- Muscia, Gisela C.,De Mara, Leonardo O.,Buldain, Graciela Y.,Ass, Silvia E.
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p. 647 - 650
(2016/04/19)
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- Simple and efficient synthesis of tetrahydro-β-carbolines via the Pictet-Spengler reaction in 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP)
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1,1,1,3,3,3-Hexafluoro-2-propanol (HFIP) can act as both the solvent and the catalyst to promote the Pictet-Spengler reactions between tryptamine derivatives and aldehydes or activated ketones. For most substrates, removing the low boiling point HFIP by distillation directly afforded tetrahydro-β-carbolines in high yields.
- Wang, Li-Na,Shen, Su-Li,Qu, Jin
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p. 30733 - 30741
(2014/08/05)
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- An acid-free Pictet-Spengler reaction using deep eutectic solvents (DES)
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Deep eutectic solvents (such as the combination of either urea or glycerol with choline chloride) are effective solvents/organocatalysts for Pictet-Spengler condensations to form carbolines. The reaction conditions are quite mild and do not require additi
- Handy, Scott,Wright, Matthew
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p. 3440 - 3442
(2014/06/09)
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- A facile and efficient synthesis of tetrahydro-β-carbolines
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This Letter describes a convenient, efficient, and clean synthesis of various tetrahydro-β-carbolines catalyzed by propane phosphonic acid anhydride T3P under microwave irradiation.
- Desroses, Matthieu,Koolmeister, Tobias,Jacques, Sylvain,Llona-Minguez, Sabin,Jacques-Cordonnier, Marie-Caroline,Cázares-K?rner, Armando,Helleday, Thomas,Scobie, Martin
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supporting information
p. 3554 - 3557
(2013/07/05)
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- Mild and efficient cyanuric chloride catalyzed Pictet-Spengler reaction
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A practical, mild and efficient protocol for the Pictet-Spengler reaction catalyzed by cyanuric chloride (trichloro-1,3,5-triazine, TCT) is described. The 6-endo cyclization of tryptophan/tryptamine and modified Pictet-Spengler substrates with both electr
- Sharma, Ashish,Singh, Mrityunjay,Rai, Nitya Nand,Sawant, Devesh
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p. 1235 - 1242
(2013/07/26)
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- Comparative evaluation of a Pictet-Spengler protocol in microwave-assisted conversions of tryptamine with aryl- and carboxyaryl aldehydes: Role of ring strain in cyclocondensation of the primarily formed carboxyaryl-substituted β-carbolines
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An efficient microwave-assisted Pictet-Spengler protocol employing boric acid/acetic acid as a catalytic system was elaborated for the synthesis of 1-aryl-β-carbolines. Under the novel conditions tryptamine and 2-formylbenzoic acid furnished a pentacyclic
- Fodor, Kinga-Judit,Kocsis, Vasile-Ludovic,Kiss, Kolos,Karolyi, Benedek-Imre,Szabolcs, Armin,Silaghi-Dumitrescu, Luminita,Csampai, Antal
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p. 1381 - 1387
(2013/10/01)
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- O-Benzenedisulfonimide as a reusable acid catalyst for an easy, efficient, and green synthesis of tetrahydroisoquinolines and tetrahydro-β-carbolines through Pictet-Spengler reaction
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The synthesis of tetrahydroisoquinolines and tetrahydro-β-carbolines, using the Pictet-Spengler reaction, was carried out in the presence of a catalytic amount of o-benzenedisulfonimide, which worked as a Br?nsted acid organocatalyst. The reaction conditi
- Barbero, Margherita,Bazzi, Stefano,Cadamuro, Silvano,Dughera, Stefano
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experimental part
p. 6356 - 6359
(2011/01/04)
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- Iodine-catalyzed highly effective pictet-spengler condensation: An efficient synthesis of tetrahydro-β-carbolines
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Molecular iodine was found to be an efficient catalyst for the two-component Pictet-Spengler condensation of tryptamine with aldehydes, which leads to the formation of tetrahydro-β-carbolines in high yields. Copyright Taylor & Francis Group, LLC.
- Prajapati, Dipak,Gohain, Mukut
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experimental part
p. 4426 - 4433
(2009/04/06)
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- Water as an efficient medium for the synthesis of tetrahydro-β-carbolines via Pictet-Spengler reactions
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A mild and efficient protocol for the Pictet-Spengler reaction in water using an acid catalyst has been described. The condensation of tryptophan, tryptamine, and Nb-benzyl tryptophan with different aldehydes having both electron-withdrawing and -donating substituents in the presence of a catalytic amount of TFA in water furnished tetrahydro-β-carbolines in good isolated yields. A salient feature of the water mediated Pictet-Spengler reaction was the general trend observed during the condensation of Trp-OMe and aryl/aliphatic aldehydes furnishing diastereomeric mixtures with a preference for the cis-isomer.
- Saha, Biswajit,Sharma, Sunil,Sawant, Devesh,Kundu, Bijoy
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p. 1379 - 1383
(2007/10/03)
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- Development of the Pictet-Spengler reaction catalyzed by AuCl 3/AgOTf
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Mild and efficient AuCl3/AgOTf-catalyzed Pictet-Spengler reactions were developed to afford in good yields a variety of tetrahydroisoquinoline and tetrahydro-β-carboline ring systems, which constitute important motifs in biologically active nat
- Youn, So Won
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p. 2521 - 2523
(2007/10/03)
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- The preparation and evaluation of 1-substituted 1,2,3,4-tetrahydro- and 3,4-dihydro-β-carboline derivatives as potential antitumor agents
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A series of 1-substituted 1,2,3,4-tetrahydro- and 3,4-dihydro-β- carboline derivatives have been synthesized and evaluated for antitumor activity against murine P-388 and human tumor cell lines, KB-16, A-549 and HT-29. All of the compounds prepared, excep
- Shen, Ya-Ching,Chen, Ching-Yeu,Hsieh, Pei-Wen,Duh, Chang-Yih,Lin, Yat-Min,Ko, Chin-Lien
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- Potassium superoxide as an alternative reagent for Winterfeldt oxidation of beta-carbolines.
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Potassium superoxide was examined as an alternative oxidation reagent for the Winterfeldt reaction. KO(2) was found to be superior to the original Winterfeldt protocol for base-sensitive substrates. [reaction--see text]
- Jiang, Weiqin,Zhang, Xuqing,Sui, Zhihua
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- Highly efficient Lewis acid-catalysed Pictet-Spengler reactions discovered by parallel screening
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High yielding Lewis acid-catalysed one-pot Pictet-Spengler reactions of tryptophan methyl ester and tryptamine with aliphatic and aromatic aldehydes were achieved in short reaction times with the aid of microwave irradiation.
- Srinivasan, Natarajan,Ganesan
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p. 916 - 917
(2007/10/03)
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- 1-substituted 1,2,3,4-tetrahydro-beta-carboline and 3,4-dihydro-beta-carboline and analogs as antitumor agents
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A composition includes a substituted dihydro- or tetrahydro-β-carboline of formula (II) or (III), wherein the aromatic ring of the carboline may include one or more substituents selected from the group consisting of hydroxy, C1-6 alkoxy, benzyloxy, C1-6 acyloxy, amino, C1-6 alkyl, C1-6 dialkylamino, halogen, and carboxy, and the C-1 position of the carboline may include a substitutent selected from the group consisting of a carbocyclic group and a heterocyclic group. The composition may include a salt or a prodrug of the substituted dihydro- or tetrahydro-β-carboline. The composition may further includes a pharmaceutically acceptable carrier, diluent, or excipient.
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- Pictet-Spengler reaction of nitrones and imines catalyzed by Yb(OTf)3-TMSCI
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The Pictet-Spengler reaction of nitrones and imines prepared from N-hydroxytryptamine and tryptamine gave the corresponding tetrahydro-β-carbolines in excellent yields in the presence of Yb(OTf)3-TMSCl in a mixture of CH2Cl2/su
- Tsuji, Riichiro,Yamanaka, Masamichi,Nishida, Atsushi,Nakagawa, Masako
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p. 428 - 429
(2007/10/03)
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- Synthesis of 2-acyltetrahydro-β-carbolines by an intramolecular α- amidoalkylation reaction
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2-Acyltetrahydro-β-carbolines 7 have been obtained by cyclization of adducts 5 from imines 3 of tryptamine 1 and aldehydes 2 with acyl chlorides 4 as a result of an intramolecular α-amidoalkylation reaction in the presence of bases as N,N-dimethylaniline or Et3N.
- Venkov, Atanas P.,Boyadjieva, Atanaska K.
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p. 487 - 494
(2007/10/03)
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- Mild Oxidation of 1,2,3,4-Tetrahydro-β-carbolines
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Oxidation of 1-(aryl or heteroaryl)-1,2,3,4-tetrahydro-β-carbolines (1a-r) with KMnO4 in dry THF afforded in the most cases almost exclusively 3,4-dihydro products (2) with a yield of 28-94percent.Only in few cases (1c, 1i, 1m) the reaction was non-selective and a significant amount of the fully aromatized products (3) (30-40percent of the reaction mixture) was observed.The influence of both the substituent nature and the substitution modes on the observed yield and selectivity of the reaction was discussed.Key words: 1,2,3,4-tetrahydro-β-carbolines, 3,4-dihydro-β-carbolines, selective oxidation, oxidation with KMnO4 in cold THF, substituent effect
- Mokrosz, M.J.,Paluchowska, M.H.,Misztal, S.
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p. 264 - 268
(2007/10/02)
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