• Title/Summary/Keyword: Regioselective reaction

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Studies on the Regioselective and Diastereoselective Amination using Chlorosulfonyl Isocyanate (CSI)

  • Kim, In-Su;Jung, Young-Hoon
    • Proceedings of the PSK Conference
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    • 2003.04a
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    • pp.239.2-240
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    • 2003
  • We have recently described the novel synthetic method for N-protected amines from various ethers using chlorosulfonyl isocyanate(CSI) and found that the mechanism of our CSI reaction is a competitive reaction of SN1 and SNi mechanism according to the stability of carbocation intermediate. Forthermore. we developed the regioselective and diastereoselective one-pot synthetic method for 1,2-amino alcohol, through the reaction of di-and tribenzyl thers with CSI, and invetigated its mechanism. (omitted)

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Efficient and Regioselective Ring-Opening of Epoxides with Alcohols and Sodium Azide by using Catalytic Amounts of GaCl3/Polyvinylpyrrolidone

  • Pourali, Ali Reza;Ghayeni, Samaneh;Afghahi, Fatemeh
    • Bulletin of the Korean Chemical Society
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    • v.34 no.6
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    • pp.1741-1744
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    • 2013
  • A new polymeric catalyst was prepared by supporting $GaCl_3$ on cross-linked polyvinylpyrrolidone ($GaCl_3$/PVP). This catalyst was employed for efficient and regioselective ring-opening reaction of epoxides by various alcohols under solvent-free conditions at room temperature. In our procedure, this heterogeneous catalyst was used at neutral and mild reaction conditions to afford high yields of ${\beta}$-alkoxy alcohols. Also, regioselective conversion of epoxides to ${\beta}$-azidohydrines was accomplished by sodium azide in MeOH in the presence of $GaCl_3$/PVP at room temperature. $GaCl_3$/PVP is a non-hygroscopic and recoverable catalyst and is easily separated from reaction mixture by a simple filtration and re-used repeatedly. Also, this catalyst has good handling and can be stored for long time without any reducing of its reactivity.

A Green One-Pot Protocol for Regioselective Synthesis of New Substituted 7,8-Dihydrocinnoline-5(6H)-ones

  • Khalafy, Jabbar;Rimaz, Mehdi;Ezzati, Mahnaz;Prager, Rolf H.
    • Bulletin of the Korean Chemical Society
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    • v.33 no.9
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    • pp.2890-2896
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    • 2012
  • A simple regioselective synthesis of cinnoline derivatives was achieved by a one-pot three component synthetic methodology. New substituted 7,8-dihydrocinnolin-5(6H)-ones are prepared via one-pot three component reaction of arylglyoxals with 1,3-cyclohexanedione and dimedone in the presence of hydrazine hydrate in moderate to good yields.

Regioselective Friedel-Crafts Reaction of Allyldichlorosilane with 3,4-Benzo-1,1-dichloro-1-dichloro-1-silacyclopentene

  • 박영태;박상욱;김호창
    • Bulletin of the Korean Chemical Society
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    • v.16 no.12
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    • pp.1208-1212
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    • 1995
  • A 86:14 isomeric mixture of 3,4-[3'-(dichlorosilyl)isopropyl]benzo-1,1-dichloro-1-silacyclopentene and 3,4-[2'-(dichlorosilyl)isopropyl]benzo-1,1-dichloro-1-silacyclopentene was prepared by the regioselective Friedel-Crafts reaction of allyldichlorosilane with 3,4-benzo-1,1-dichloro-1-silacyclopentene catalyzed by Lewis acid AlCl3. The structure of the products was confirmed by methylation with methylmagnesium bromide and by methoxylation with trimethylorthoformate.