- One-pot enantioselective synthesis of (S)-spirobrassinin and non-natural (S)-methylspirobrassinin from amino acids using a turnip enzyme
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Abstract: The enantioselective synthesis of (S)-(?)-spirobrassinin, which features a unique sulfur-containing spirooxindole skeleton, was achieved by focusing on the phytoalexin generation in Brassicaceae plants. Specifically, (S)-(?)-spirobrassinin was obtained in a one-pot fashion from l-tryptophan through a reaction involving S-spirocyclization with various turnip enzymes and constituents, i.e., using the turnip as a reaction reagent, catalyst, and reaction vessel. Surprisingly, this strategy also enabled the one-pot enantioselective synthesis of the novel non-natural spirooxindole (S)-(?)-5-methylspirobrassinin from 5-methyl-dl-tryptophan. Graphic abstract: [Figure not available: see fulltext.]
- Ryu, Kaori,Nakamura, Seikou,Nakashima, Souichi,Matsuda, Hisashi
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p. 308 - 318
(2021/01/07)
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- A concise synthesis of cyclobrassinin and its analogues via a thiyl radical aromatic substitution
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A simple and concise approach for the synthesis of cyclobrassinin has been developed through a thiyl radical-mediated intramolecular aromatic substitution, with benzoyl peroxide as an efficient initiator and oxidant. The current method can also be utilized in the synthesis of 6 and 7-membered ring cyclobrassinin analogues in moderate to good yields. The transformation involves a formal radical 6 and 7-endo-trig cyclization of the corresponding dithiocarbamate derivatives, which were generated from indole-3-methanamines and tryptophan.
- Zhong, Xin,Chen, Ning,Xu, Jiaxi
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p. 13549 - 13557
(2018/08/21)
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- A novel palladium-catalyzed cyclization of indole phytoalexin brassinin and its 1-substituted derivatives
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A novel simple synthetic approach to spiroindoline phytoalexins and their derivatives has been developed. The spirocyclization of brassinin and its 1-substituted derivatives was achieved using palladium catalyst PdCl 2(CH3CN)2 in DMSO at 80°C in the presence of water, methanol or aniline.
- Budovska, Mariana
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p. 5575 - 5582
(2014/01/23)
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- Novel IDO inhibitors and methods of use thereof
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Novel indoleamine 2,3-dioxygenase (IDO) inhibitors, compositions comprising the same, and methods of use thereof are disclosed.
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Page/Page column Sheet 2/7; 7
(2010/11/27)
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- Structure-activity study of brassinin derivatives as indoleamine 2,3-dioxygenase inhibitors
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A screen of indole-based structures revealed the natural product brassinin to be a moderate inhibitor of indoleamine 2,3-dioxygenase (IDO), a new cancer immunosuppression target. A structure-activity study was undertaken to determine which elements of the brassinin structure could be modified to enhance potency. Three important discoveries have been made, which will impact future IDO inhibitor development: (i) The dithiocarbamate portion of the brassinin lead is a crucial moiety, which may be binding to the heme iron of IDO; (ii) an indole ring is not necessary for IDO inhibition; and (iii) substitution of the S-methyl group of brassinin with large aromatic groups provides inhibitors that are three times more potent in vitro than the most commonly used IDO inhibitor, 1-methyl-tryptophan.
- Gaspari, Paul,Banerjee, Tinku,Malachowski, William P.,Muller, Alexander J.,Prendergast, George C.,DuHadaway, James,Bennett, Shauna,Donovan, Ashley M.
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p. 684 - 692
(2007/10/03)
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- Toward the control of Leptosphaeria maculans: Design, syntheses, biological activity, and metabolism of potential detoxification inhibitors of the crucifer phytoalexin brassinin
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Brassinin (1), a crucial plant defense produced by crucifers, is detoxified by the phytopathogenic fungus Leptosphaeria maculans (Phoma lingam) to indole-3-carboxaldehyde using a putative brassinin oxidase. Potential inhibitors of brassinin detoxification
- Pedras, M. Soledade C.,Jha, Mukund
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p. 4958 - 4979
(2007/10/03)
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- Synthesis of thiazino[6,5-b]indole derivatives, analogues of the phytoalexin cyclobrassinin. A new method for preparation of 3-aminomethylindole
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An efficient non-reductive synthesis of 3-aminomethylindole (6) was developed from gramine (1) via 3-phthalimidomethylindole (2). The reactions of amine 6 with substituted methyl dithiobenzoates gave 3- (arylthiocarbonylaminomethyl)indoles. The Hugerschoff ring-closure reactions of the thiobenzamide intermediates (11a-f) with phenyltrimethylammonium tribromide and subsequent basic treatment furnished 2-arylthiazino[6,5-b]indole derivatives (14a-f). By use of the latter bromine source, the phytoalexin cyclobrassinin (8) was prepared in a considerably higher yield than described previously. The structures of the novel products were elucidated by IR, 1H and 13C NMR spectroscopy, including 2D-HMQC, 2D-HMBC and DEPT measurements.
- Csomós, Péter,Fodor, Lajos,Sohár, Pál,Bernáth, Gábor
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p. 9257 - 9262
(2007/10/03)
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- New syntheses of indole phytoalexins and related compounds
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Synthesis of indole phytoalexins brassinin, brassitin, cyclobrassinin and related compounds via 3-aminomethylindole and its 1-substituted derivatives obtained by nickel boride catalyzed reduction of corresponding aldoximes with sodium borohydride and via [1-(t-butoxycarbonyl)-indol-3-yl]methyl isothiocyanate, the first stable derivative of indol-3-ylmethyl isothiocyanate is described. Antifungal activity of the prepared compounds was examined by using the fungus Bipolaris leersiae by t.l.c. bioassay and quantitative screening was carried out with the selected compounds.
- Kutschy, Peter,Dzurilla, Milan,Takasugi, Mitsuo,Toeroek, Marcel,Achbergerova, Ingrid,Homzova, Renata,Racova, Maria
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p. 3549 - 3566
(2007/10/03)
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- Synthesis of Indole Phytoalexins Brassinin and Cyclobrassinin via [1-(tert-Butoxycarbonyl)indol-3-yl]-methyl Isothiocyanate as the Key Biomimetic Intermediate
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A four-step synthesis of 1-protected indol-3-ylmethyl isothiocyanates from indole-3-carboxaldehyde has been elaborated. [1-(tert-Butoxycarbonyl)indol-3-yl]methyl isothiocyanate appeared to be a suitable biomimetic intermediate for the synthesis of protected phytoalexins brassinin and cyclobrassinin. Removing of the tert-butoxycarbonyl protecting group under specific conditions afforded phytoalexins identical with previously described compounds.
- Kutschy, Peter,Achbergerová, Ingrid,Dzurilla, Milan,Takasugi, Mitsuo
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p. 289 - 290
(2007/10/03)
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- Biosynthesis of cruciferous phytoalexins
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We report the results of biosynthetic studies on the sulfur-containing indole phytoalexins, antimicrobial compounds produced by plants after exposure to microorganisms. Feeding experiments with UV-irradiated sliced turnip root (Brassica campestris ssp. ra
- Monde, Kenji,Takasugi, Mitsuo,Ohnishi, Toshiyuki
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p. 6650 - 6657
(2007/10/02)
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- A SIMPLE SYNTHESIS OF A PHYTOALEXIN, METHOXYBRASSININ
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A simple and an alternative multi-gram scale synthetic method methoxybrassinin is developed starting from indole-3-carboxaldehyde.
- Somei, Masanori,Kobayashi, Kensuke,Shimizu, Kazuhisa,Kawasaki, Toshiya
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- Novel Sulfur-Containing Phytoalexins from the Chinese Cabbage Brassica campestris L. ssp. pekinensis (Cruciferae)
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The first isolation and structure elucidation of four sulfur-containing indole phytoalexins from Chinese cabbage inoculated with Pseudomonas cichorii are described.
- Takasugi, Mitsuo,Monde, Kenji,Katsui, Nobukatsu,Shirata, Akira
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p. 285 - 290
(2007/10/02)
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- Isolation of Three Novel Sulphur-containing Phytoalexins from the Chinese Cabbage Brassica campestris L. ssp. pekinensis (Cruciferae)
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Inoculation of Chinese cabbage heads with the bacterium Pseudomonas cichorii induced the production of three major phytoalexins named methoxybrassinin (1), brassinin (2), and cyclobrassinin (3), whose structures have been elucidated on the basis of spectroscopic studies and synthesis.
- Takasugi, Mitsuo,Katsui, Nobukatsu,Shirata, Akira
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p. 1077 - 1078
(2007/10/02)
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