- Stereocontrolled syntheses of (-)- And (+)-γ-diisoeugenol along with optically active eight stereoisomers of 7,8′-epoxy-8,7′-neolignan
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It was shown that reduction of the tertiary benzylic hydroxy group of (2R,3S,4R,5S)-3,5-bis(4-benzyloxy-3-methoxyphenyl)-2,4-dimethyltetrahydro-3-furanol 17 followed by the intramolecular Friedel-Crafts reaction gave exclusively indane with (7S,7′S,8R,8′R)-2,7′-cyclo-7,8′-neolignan structure 18 along with (7S,7′R,8S,8′R)-7,8′-epoxy-8,7′-neolignan structure 19. Indane 18 was converted to (-)-γ-diisoeugenol ((-)-4). On the other hand, (2S,3R,4R,5S)-3,5-bis(4-benzyloxy-3-methoxyphenyl)-2,4-dimethyltetrahydro-3-furanol 22 did not afford indane, but the tetrahydrofuran structure with (7S,7′S,8S,8′S)-7,8′-epoxy-8,7′-neolignan structure 23 and 7′-epi-23.
- Takubo, Tatsuaki,Kikuchi, Nao,Nishiwaki, Hisashi,Yamauchi, Satoshi
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p. 2168 - 2176
(2021/03/26)
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- holds the non-rope to divide method for the preparation of intermediates
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The invention relates to a preparation method of a tofisopam intermediate 3-[2-(3,4-dimethoxy benzoic acyl)-4,5-dimethoxyphenyl]-penta-2-ketone, and belongs to the technical field of pharmaceutical synthesis. The method comprises the following step: carrying out reaction on 1-(3,4-dimethoxy-phenyl)-3-ethyl-5,6-dimethoxy-2-methyl-indan as an initial material, copper compounds as catalysts, and hydrogen peroxide as an oxidant under an acid condition, so as to prepare the tofisopam intermediate 3-[2-(3,4-dimethoxy benzoic acyl)-4,5-dimethoxyphenyl]-penta-2-ketone. According to the preparation method, the content of heavy metals in the wastewater is greatly lowered, chromium compounds with carcinogenesis are avoided, the production capacity of tofisopam is released, and the environment is protected.
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Paragraph 0026-0029
(2017/02/24)
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- Gold-Catalyzed Dimeric Cyclization of Isoeugenol and Related 1-Phenylpropenes in Ionic Liquid: Environmentally Friendly and Stereoselective Synthesis of 1,2,3-Trisubstituted 2,3-Dihydro-1 H -indenes
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Gold-catalyzed dimerization of isoeugenol and related 1-phenylpropenes in ionic liquid enabled environmentally friendly, stereoaselective synthesis of 1,2,3-trisubstituted 2,3-dihydro-1H-indenes. Dimerization of isoeugenol or isohomogenol afforded diisoeu
- Morita, Nobuyoshi,Mashiko, Rie,Hakuta, Dai,Eguchi, Daisuke,Ban, Shintaro,Hashimoto, Yoshimitsu,Okamoto, Iwao,Tamura, Osamu
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p. 1927 - 1933
(2016/07/06)
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- First green protocols for the large-scale preparation of γ-diisoeugenol and related dihydro(1H)indenes via formal [3+2] cycloaddition reactions
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Trans-isoeugenol and related styrenes (trans-isohomogenol or O-benzylated isoeugenol), important components of the essential oil of various tropical plants, dimerize easily in the presence of catalytic amounts of BF3·OEt2 in poly(ethylene glycol) with Mn = 400 (PEG-400) or SiO2-OSO3H in MeCN via formal [3+2] cycloaddition reaction to give respective natural products (diisoeugenol and its O-substituted analog) with the 1,2-trans-2,3-trans-configuration in excellent yields. γ-Diisoeugenol scale-up preparation has also been described.
- Kouznetsov, Vladimir V.,Merchan Arenas, Diego R.
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experimental part
p. 1546 - 1549
(2009/06/21)
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- Anomalous behaviour of Pd(II) on phenylpropanoids
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Exposure of phenylpropanoids like methyleugenol, eugenol and methylchavicol to Pd(II) chloride in acetic acid results in α,β linked unsymmetrical dimers. Dimeric coupling is characteristic of phenylpropanoids whereas cyclisation to indanes require the pre
- Thappa,Agarwal,Dhar
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p. 731 - 733
(2007/10/03)
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- Studies on chromium trioxide-based oxidative coupling reagents and synthesis of lignan-cagayanone
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Oxidation of 1-arylprop-1-enes by using the reagent system CrO3-HClO4- CH3CN at 0-5°C gave seven products from methyl isoeugenol, five from ethyl isoeugenol, four from benzyl isoeugenol, and five from isosafrole. Cagayanone was obtained from isosafrole in one step. The structures of the products were elucidated and the mechanism of their formation is discussed.
- Kuo,Lin
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p. 1507 - 1512
(2007/10/02)
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- Synthesis of r-1-Ethyl-t-2-methyl-t-3-arylindans
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Although there are four possible racemates of the 1-ethyl-2-methyl-3-arylindans (α, β, γ and δ), only three (α, β and γ) have been synthesized or obtained from propenylbenzenes with acid reagents.Now we present a synthetic route for the preparation of the
- Alesso, Elba N.,Iglesias, Graciela Y. Moltrasio,Mufato, Jorge D.,Aguirre, Jose M.
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p. 1753 - 1758
(2007/10/02)
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- Reaction of some N-acyl-1-alkylamines with polyphosphoric ester PPE: nuclear magnetic resonance and stereochemistry of reaction products
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Phenylindanes were obtained from the reaction of N-acyl-1-arylalkylamines with polyphosphoric ester (PPE). cis-1-Methyl-3-(3,4-dimethoxyphenyl)-5,6-dimethoxyindane was synthesized to determine which stereoisomer was produced by N-formyl and N-acetyl-1-(3,4-dimethoxyphenyl)ethylamine with PPE.Nuclear magnetic resonance specta (1H and 13C) of several mono-, 1,3-di-, and 1,2,3-tri-substituted indanes were fully analyzed to provide information on steric interactions and conformation of the cyclopentene ring.Possible cyclodimerization pathways are proposed.
- Alesso, Elba N.,Tombari, Dora G.,Iglesias, Graciela Y. Moltrasio,Aguirre, Jose M.
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p. 2568 - 2574
(2007/10/02)
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