• Title/Summary/Keyword: ${\alpha},{\beta}-unsaturated\

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Reaction of Lithium 2-Pyridyloxyalkylcuprates Having Improved Thermal Stability with Acid Chlorides and $\alpha,\beta$-Unsaturated Ketones

  • Lee, Phil-Ho;Shim, Sang-Chul;Kim, Sung-Gak
    • Bulletin of the Korean Chemical Society
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    • v.7 no.6
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    • pp.425-428
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    • 1986

  • A new heterocuprate containing 2-pyridyloxy ligand, lithium 2-pyridyloxy-n-butylcuprate, has shown improved thermal stability and it reacts with acid chlorides to afford the corresponding ketones in high yields. Similarly, it can be effectively utilized in conjugate addition reactions of $\alpha,\beta$-unsaturated ketones. Of synthetic significance is that the complete utilization of n-butyl group in lithium 2-pyridyloxy-n-butylcuprate has been observed.

  • https://doi.org/10.5012/bkcs.1986.7.6.425 인용 PDF

Clean Reduction of $\alpha,\beta$-Unsaturated Carboxylic Acid Derviatives to the Saturated Derivatives by Potassium Triphenylborohydride in the Presence of Phenol

  • Park, Soo-Bong;Kim, Kwan-Eung;Yoon, Nung-Min
    • Bulletin of the Korean Chemical Society
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    • v.9 no.6
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    • pp.352-355
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    • 1988

  • ${\alpha},{\beta}$-unsaturated carboxylic acid derivatives such as esters, amides, and nitriles are readily reduced to the corresponding saturated derivatives by potassium triphenylborohydride, $KPh_3BH$, in the presence of phenol, a quenching agent, in excellent yields.

  • https://doi.org/10.5012/bkcs.1988.9.6.352 인용 PDF

A New HPLC-analytical Method for Total Sphingosine Contents as an Indirect Index for the Ganglioside Contents of Deer Antlers

  • Choi, Hye-Ok;Kim, Jeung-Won;Jo, Sung-Jun;Kim, Jung-Hwan;Han, Byung-Hoon
    • Natural Product Sciences
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    • v.17 no.4
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    • pp.315-320
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    • 2011

  • Routinely applicable HPLC assay procedures for the ganglioside content in various deer antler preparations were established through the creation of a UV-absorbing chromophoric substance - trans-${\alpha},{\beta}$-unsaturated-hexadecene-aldehyde - from the sphingosine moiety in ganglioside molecules by two step chemical reactions. In order to guarantee the assay's accuracy and sensitivity, the HPLC-assay procedure adopted internal reference procedures by mixing cis-${\alpha},{\beta}$-unsaturated-hexadecene aldehyde[V] or cis-3-heptadecene- 1,2-diol[IV] to assay samples. The internal reference compound [IV] or [V] was synthesized in our laboratory starting from mannitol-diacetonide through three or four step organic reactions. This new HPLC-assay procedure was successfully applied to deer antler extracts with good dose-dependent calibration curves at the picomole level of gangliosides.

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Selective Epoxidation and Reduction of Rigid Cyclic ${\alpha},{\beta}$-Unsaturated Carbonyl Compounds (환상 ${\alpha},{\beta}$-불포화 카르보닐 화합물의 선택적 에폭시화 및 환원)

  • Ma, Eun-Sook
    • YAKHAK HOEJI
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    • v.49 no.6
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    • pp.443-448
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    • 2005

  • Diosgenin (25 (R) - spirost-5-en-3$\beta$ -ol) was oxidized with 2,3-dichloro -5,6-dicyano-1,4-benzoquinone to form 25(R)-1,4,6-spirostatrien-3-one (1) as rigid cyclic $\alpha$,$\beta$-unsaturated carbonyl compound. This compound was reacted with $H_{2}O_{2}$, m-chloroperoxybenzoic acid (mCPBA), NaOCl in the presence with (R,R)- or (S,S)-Jacobsen catalyst, tert-butyl-hydroperoxide (TBHP) in Mo$(CO)_{6}$, and in VO $(acac)_{2}$ catalyst, respectively, 25(R) -1,4,6-spirostatrien -3-one (1) was reduced with $NaBH_{4}$ L-Selectride, $LiAIH_{4}$,$BH_{3}$ $\cdot$$(CH_{3})_{2}S$, Superhydride, Red-Al, and lithium tri-tert-butoxyaluminium hydride. And 25(R)-4,6-spirostadien-3$\beta$-ol (4) was treated with $H_{2}O_{2}$, mCPBA, TBHP in D - (-) - and L-(+)-diisopropyltar-trate and $Ti(OiPr)_{4}$ condition (Sharpless asymmetric epoxidation), TBHP in $Mo(CO)_{6}$, and in $VO(acac)_{2}$ catalyst, respectively.

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