• Title/Summary/Keyword: lactone

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A Total Synthesis of Aliskiren Starting from D-Tartrate Diester

  • Kim, Ji Hei;Ko, Soo Y.
    • Bulletin of the Korean Chemical Society
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    • v.34 no.12
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    • pp.3777-3781
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    • 2013
  • A formal total synthesis of aliskiren was accomplished. A key in our synthesis was to use the symmetric ciscisoid-cis-bis-lactone 3' as a precursor, which was prepared from D-tartrate diester. Appending the end groups and functional group transformations completed the synthesis.

A Study on the Knoevenagel Reaction of Fluorinated Carbonyl Compounds (含弗素有機 Carbonyl化合物의 Knoevenagel反應에 關한 硏究)

  • You Sun Kim
    • Journal of the Korean Chemical Society
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    • v.7 no.1
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    • pp.85-90
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    • 1963
  • The Knoevenagel reaction of fluorinated carbonyl compounds, 1,1,1-trifluoro-propanone-2-heptafluoro-butyraldehyde, 1,3-dichloro-1,1,3,3-tetrafluoro-acetone, tetradecafluoro-heptanone-4 and 2,2,2-trifluoro-acetophenone yielded fluorinated ${\beta},{\beta}$-dialkyl-${\beta}$-hydroxy acids. Dehydration of the acids do not give the olefinic acid in the case of the perfluorinated system and gave a lactone. From the consideration of electronic and steric effects a mechanismic path of the reaction via a carbanion intermediate was proposed for the reaction. Preparation of related derivatives are also described.

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Dentatins: Sesquiterpene Glucosides from lxeris dentata

  • Chung, Ha-Sook;Woo, Won-Sik;Lim, Sook-Ja
    • Archives of Pharmacal Research
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    • v.17 no.5
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    • pp.323-326
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    • 1994
  • Three new sesquiterpene lactone glucosides named dentatins A, B and C were isolated from lxeris dentata and the structures were elucidated as $3{\betha}, {\;}8{\betha}-dihydroxy-(1{\alpha}, 5{\alpha})guainan-10(14)-ene-6{\alpha}, {;\}12-olide-3-O-{\betha}-D-giucopyuranoside{\;}(1), {\;}3{\betha}, {\;}8{\betha}-dihydroxy-(1{\alpha}, {\;}5{\alpha})-guaian-4(15), {\;}10(14)-diene-6{\alpha}, {\;}12-plide-3-O-{\betha}-D-glucopyranoside{\;}(3)$, respectively, on the basis of spectral evidence.

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DIVERGENT ROLES OF A NOVEL PHOSPHOLIPASE $A_2$ IN CELL DEATH

  • Schnellmann, Rick G.
    • Proceedings of the Korean Society of Toxicology Conference
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    • 2002.11b
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    • pp.68-88
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    • 2002
  • Phospholipase A$_2$ (s) are esterases that hydrolyze the sn-2 ester bond in phospholipids, releasing a fatty acid and a lysophospholipid. We previously showed that most PLA$_2$ activity in rabbit renal proximal tubule cells (RPTC) was Ca$\^$2+/-independent, localized to the endoplasmic reticulum (ER-iPLA$_2$), and inhibited by the specific Ca$\^$2+/-independent PLA$_2$ inhibitor bromoenol lactone (BEL).(omitted)

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Malyngolide Analogues. Synthesis of (${\pm}$)-Dehydromalyngolide and (${\pm}$)-Isomalyngolide

  • Sunggak Kim;Youn Chul Kim;Chang Yong Hong
    • Bulletin of the Korean Chemical Society
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    • v.5 no.3
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    • pp.97-100
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    • 1984
  • Two novel malyngolide analogues, (${\pm}$)-dehydromalyngolide and (${\pm}$)-isomalyngolide, of (-)-malyngolide antibiotic have been synthesized by application of our previously developed synthetic sequence for the synthesis of (${\pm}$)-malyngolide. Dehydromalyngolide was synthesized from the known lactone (4) in a 55 % overall yield in six steps, while isomalyngolide was synthesized from the readily available keto ester (11) in a 56 % overall yield in four steps.