• Title/Summary/Keyword: Acetylenic

Search Result 28, Processing Time 0.03 seconds

Asymmetric Reduction of Prochiral $\alpha,\beta$-Acetylenic Ketones With Potassium 9-0-(1,2 : 5,6-Di-O-isopropylidene-$\alpha$-D-glucofuranosyl)-9-bortabicylco[3.3.1]nonane$^\dag$

  • Cho, Byung-Tae;Park, Won-Suh
    • Bulletin of the Korean Chemical Society
    • /
    • v.8 no.4
    • /
    • pp.257-260
    • /
    • 1987
  • The asymmetric reduction of representative prochiral ${\alpha},{\beta}$-acetylenic ketones with a new chiral borohydride reducing agent, potassium 9-0-(1,2: 5,6-Di-O-isopropylidene-${\alpha}$ -D-glucofuranosyl)-9-boratabicyclo[3.3.1]nonane, 1, in THF at $-78^{\circ}C$ was studied. Structurally different acetylenic ketones such as internal ${\alpha},{\beta}$-acetylenic ketones $RC {\equiv} CCOCH_3$ and terminal ${\alpha},{\beta}$-acetylenic ketones $HC {\equiv} CCOR$ were chosen. Thus, the reduction of internal ${\alpha},{\beta}$-acetylenic ketones yields the corresponding propargyl alcohols, such as 67% ee for 3-hexyn-2-one, 75% ee for 5-methyl-3-hexyn-2-one, 86% ee for 5,5-dimethyl-3-hexyn-2-one, 74% ee for 3-nonyn-2-one and 61% ee for 4-phenyl-3-butyn-2-one. Terminal ${\alpha},{\beta}$-acetylenic ketones, such as 3-butyn-2-one, 1-pentyn-3-one, 4-methyl-1-pentyn-3-one and 1-octyn-3-one, are reduced to the corresponding alcohols with 59% ee, 17% ee, 44% ee and 12% ee of optical induction respectively. With one exception (4-methyl-1-pentyn-3-one), all propargyl alcohols obtained are enriched in R-enantiomers.

Synthesis of Dimeric Oligodeoxyribonucleotide (이합체성 올리고디옥시리보핵산의 합성)

  • Song, Jeong-Sup
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.8 no.6
    • /
    • pp.1566-1571
    • /
    • 2007
  • Oligodeoxyribonucleotide bearing the di-acetylenic linkage has been prepared. Staring from 5-Iodo-2'-deoxyuridine(1), a four-step sequence, consisting of the Pd(0)-catalyzed Heck-type C-C coupling with acetylenic group, protection of 5'-hydroxy group, generation of acetylenic hydrogen, and Glaser oxidative coupling reaction leads to the dimeric oligodeoxyribonucleotide(5).

  • PDF

Studies Towards Intramolecular Formal Iron-Catalyzed [4+2] Cycloaddition of Acetylenic Dienes (Fe(0) 촉매를 이용한 Acetylenic Dienes 의 분자내 [4+2] 고리화 첨가반응에 관한 연구)

  • Byeon, Sang Yong
    • Journal of the Korean Chemical Society
    • /
    • v.38 no.1
    • /
    • pp.61-68
    • /
    • 1994
  • The intramolecular formal iron-catalyzed [4+2] cycloaddition reaction of acetylenic dienes to produce bicyclic products has been investigated. These reactions proceeded, competing via intramolecular carbocyclization and bimolecular cycloaddition. However, the iron-catalyzed bicyclic carbocyclization of 4,4-dimethyl-3-(tert-butyldimethylsiloxy)-1-phenyl-6,8-decadien-1-yne(11) yielded exclusively bicyclic diene product(yield 78.1%). From this result, we found that the substrate containing a dimethyl substitutent at the 4,4-position helped to promote the intramolecular reaction, which is stable to the iron catalyzed conditions.

  • PDF

Stereoselective Synthesis of (7Z, 11E)-7, 11-Hexadecadien-1-yl Acetate, Sex Pheromone of the Angoumois Grain Moth

  • Kang, Suk-Ku;Yoo, Kyung-Ok;Moon, Hong-Sik
    • Bulletin of the Korean Chemical Society
    • /
    • v.8 no.4
    • /
    • pp.235-237
    • /
    • 1987
  • (7Z, 11E)-7, 11-Hexadecadien-1-yl acetate(1), the sex pheromone of the female Angoumois grain moth, Sitotroga cerealella, was synthesized via the acetylenic intermediate, (11E)-11-hexadecen-7-yn-ol THP ether(2). The acetylenic compound was prepared from 7-octyn-1-ol THP ether(4) and (3E)-1-bromo-3-octene(3). The (E)-homoallylic bromide 3 was synthesized by the Julia olefin synthesis of 1-cyclopropylpentan-1-ol(6).

Mechanism of the Monoamine Oxidase Inhibition (Monoamine Oxidase의 억제 기구)

  • 강건일
    • YAKHAK HOEJI
    • /
    • v.27 no.4
    • /
    • pp.321-329
    • /
    • 1983
  • The review characterized active site(s) of MAO with respect to metal ions, hydrophobic and polar region, sulfhydryl group and flavin moiety. The mechanism of inhibition was dealt with three representative types of inhibitors; phenylcyclopropylamines, acetylenic amines, and hydrazines. Multiple forms of MAO was shortly described in relation to their selective inhibition. 84 reference were cited.

  • PDF