• Title/Summary/Keyword: Allyl ethers

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Mechanism Studies on the CSI Reaction with Allyl Ethers by Varying p-Substituent

  • Jung, Young-Hoon;Kim, Ji-Duck
    • Archives of Pharmacal Research
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    • v.26 no.9
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    • pp.667-678
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    • 2003
  • We examined the effect of p-substituents in p-substituted cinnamyl methyl ethers and 1-(p-substituted phenyl)allyl methyl ethers with CSI, and confirmed that the CSI reaction of allyl ethers (p-substituted ethers) is a competitive reaction of $S_Ni{\;}and{\;}S_N1$ mechanism according to the stability of the carbocation. And, the only terminal allylic amine was obtained through the migration reaction in thermodynamic reaction condition.

A Novel Synthetic Methods for $\alpha$-Amino Acids from Allyl Ethers via N-Allylcarbamates

  • jung, Young-Hoon;Kim, Ji-Deuk
    • Archives of Pharmacal Research
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    • v.23 no.6
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    • pp.574-578
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    • 2000
  • Protected $\alpha$-Phenyl glycine 17 and phenylalanine 18 and 19 have been synthesized through an efficient three-step sequence from the corresponding allyl ethers 5, 7, and 10. The key intermediate in this synthesis is the corresponding allylic amines prepared by reaction of allyl ethers with chlorosulfonyl isocyanate.

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PHOTOCHEMICAL REACTIONS OF PSEUDOSACCHARIN 3-ALLYL ETHER (PROBENAZOLE) AND ITS ALKYL ETHER

  • Yoon, Ung-Chan
    • Journal of Photoscience
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    • v.2 no.2
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    • pp.77-81
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    • 1995
  • Photoreactions of pseudosaccharin ethers have been investigated. Pseudosaccharin 3-allyl ether undergoes a facile photoreaction via reaction pathways involving homolysis of bond between pseudosaccharyl oxygen and 3-allyl carbon, and excited nucleophilic substitution of allyloxy group by solvent which are not quenched by oxygen present in the reaction. Product yield demonstrates that the homolysis pathway predominates over the nucleophilic substitution in ca. 7:1 ratio. In contrast, pseudosaccharin alkyl ethers follow different reaction routes to produce two products, solvent-substituted pseudosaccharin alkyl ethers and reduction products, 3-alkoxy-1, 2-benzisothiazoles. The formations of reduction products, 3-alkoxy-1, 2-benzisothiazoles are completely quenched by oxygen.

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Synthesis of Allyl Functionalized Silacrown Ethers and Their Application - A Review

  • Haque, Md Hasanul;Sohn, Honglae
    • Journal of Integrative Natural Science
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    • v.13 no.2
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    • pp.41-46
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    • 2020
  • A study is reported about the synthesis processes of various silacrown ether by the reaction of alkoxysilanes with polyethylene glycols (PEG) through transesterification. Crown ether-functionalized carbosilane dendrimers and hybrid crown ethers are also discussed. We will also address the solubility enhancement, phase-transfer catalysis of different silacrown as well as their application as Ion-selective electrodes (ISEs) and as active phase of PVC electrodes for the development of potentiometric sensors for detection of alkali-Ions.

Asymmetric [2,3]-Wittig Rearrangements in the Presence of Sparteine Derivatives

  • Jahyo Kang;Won Oh Cho;Hyung Geun Cho;Hee Jin Oh
    • Bulletin of the Korean Chemical Society
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    • v.15 no.9
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    • pp.732-739
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    • 1994
  • Asymmetric [2,3]-Wittig rearrangements of allyl propargyl ethers in hexane were performed in the presence of s-butyllithium and (-)-${\alpha}$-isosparteine which is a $C_2$-symmetric chiral ligand for the alkyllithium reagent. The reactions of (Z)-or (E)-allyl 3-trimethylsilylpropargyl ethers at -78$^{\circ}C$ showed good diastereoselectivities (74-100%) and moderate enantioselectivities (29-71%). The absolute configurations of the rearrangement products were determined by the corresponding Mosher's esters. It was found that (-)-${\alpha}$ -isosparteine induced (R) configuration at the hydroxy carbon and syn stereochemistry more favorably. The possible transition state is discussed.

Diastereoselective Synthesis of Unsaturated 1,4-Amino Alcohols as a Biologically Important Moiety

  • Jung Young Hoon;Kim Ji Duck
    • Archives of Pharmacal Research
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    • v.28 no.4
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    • pp.382-390
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    • 2005
  • chial allylic ethers with a hydroxyl group attached to the $\pi-system$ and chlorosulfonyl isocyanate. The enantioselectivity of the CSI reaction with the chiral allylic and benzylic ethers was examined in various solvents and temperatures. Based on these results, it was proposed that the CSI reaction is a competitive reaction of a $S_{N}i$ (retention) and a $S_{N}1$ mechanism (racemization) according to the stability of the carbocation intermediate. This means that there is a greater proportion of retention with the less stable the carbocation intermediate and vise versa.

Conformations of Tetrahomodioxa-p0phenylcalix[4]arene Alkyl Ethers

  • No, Kwang-Hyun;Park, Young-Ja
    • Bulletin of the Korean Chemical Society
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    • v.23 no.11
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    • pp.1629-1634
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    • 2002
  • Reaction of tetrahomodioxa p-phenylcalix[4]arene with alkyl halide and NaH in DMF leads to the title tetra-alkylated derivatives, 7,13,21,27-tetra-phenyl-29,30,31,32-tetraalkyloxy-2,3,16,17-tetrahomo-3,17-dioxacalix [4]arenes, their preferred conformations were determined by NMR spectra as C-1,2-alternate. The molecular structure of allyl derivative has been solved by X-ray diffraction methods. The molecules have a conformation with pseudo center of symmetry. The benzene ring A is up, ring C is down, B and D rings are flat with respect to the plane of the macrocyclic ring.