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

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Highly Chemo- and Regioselective Reaction of Hydroxybenzenes in Acidic Ionic Liquid

  • Guo, Hui;Zhuang, Yu Wei;Cao, Jian;Zhang, Guo Bao
    • Bulletin of the Korean Chemical Society
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    • v.34 no.9
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    • pp.2594-2596
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    • 2013
  • Highly chemo- and regioselective reaction of hydroxybenzenes with ${\alpha},{\beta}$-unsaturated compounds in acidic ionic liquid l-butyl-3-methylimidazolium hydrogen sulphate ([BMIM]HSO4) was reported for the first time. A series of oxa-Michael adducts and Friedel-Crafts alkylated products were synthesized with good yields. The acidic ionic liquid could be easily recycled for at least 5 times with only minor loss in activity.

Selective Reduction by Lithium Bis-or Tris(dialkylamino)-aluminum Hydrides. II. Reaction of Lithium Tris(dibutylamino)-aluminum Hydride with Selected Organic Compounds Containing Representative Functional Groups

  • Cha, Jin-Soon;Lee, Sung-Eun;Lee, Heung-Soo
    • Bulletin of the Korean Chemical Society
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    • v.12 no.6
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    • pp.644-649
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    • 1991
  • The approximate rates and stoichiometry of the reaction of excess lithium tris(dibutylamino)aluminum hydride (LT-DBA) with selected organic compounds containing representative functional groups under standardized conditions (tetrahydrofuran, $0^{\circ}C$) were studied in order to characterize the reducing characteristics of the reagent for selective reductions. The reducing ability of LTDBA was also compared with those of the parent lithium aluminum hydride and the alkoxy derivatives. The reagent appears to be much milder than the parent reagent, but stronger than lithium tri-t-butoxyaluminohydride in reducing strength. LTDBA shows a unique reducing characteristics. Thus, the reagent reduces aldehydes, ketones, esters, acid chlorides, epoxides, and amides readily. In addition to that, ${\alpha},{\beta}$-unsaturated aldehyde is reduced to ${\alpha},{\beta}$-unsaturated alcohol. Quinones are reduced to the corresponding diols without evolution of hydrogen. Tertiary amides and aromatic nitriles are converted to aldehydes with a limiting amount of LTDBA. Finally, disulfides and sulfoxides are readily reduced to thiols and sulfides, respectively, without hydrogen evolution.

Reactions with Activated Nitriles : A new route for the synthesis of new pyridine and pyrazolopyridine derivatives

  • Attaby, Fawzy-A.;Eldin, Sanaa-M.
    • Archives of Pharmacal Research
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    • v.13 no.3
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    • pp.274-277
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    • 1990
  • It has been found that $\alpha, \beta$-unsaturated nitrile derivatives 1-3 reached with S- methylisothiourea to give the prpone derivatives 4-6 respectively. Cyclisation of 4-6 using ethanolic hydrochloric acid afforded the pyridine derivatives 7-9 in good yields. On the other hand, the reactions of hydrazine hydrate and of phenylhydrazine with each of 7-9 gave the corresponding pyrazolopyridine derivatives 10-15. The structures of the newly synthesised derivatives were assigned on the basis of elemental analyses, IR and $^1H$-NMR spectral data studies.

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Ex vivo Digestion of Milk from Red Chittagong Cattle Focusing Proteolysis and Lipolysis

  • Islam, Mohammad Ashiqul;Ekeberg, Dag;Rukke, Elling-Olav;Vegarud, Gerd Elisabeth
    • Asian-Australasian Journal of Animal Sciences
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    • v.28 no.4
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    • pp.559-567
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    • 2015
  • Ex vivo digestion of proteins and fat in Red Chittagong Cattle milk from Bangladesh was carried out using human gastrointestinal enzymes. This was done to investigate the protein digestion in this bovine breed's milk with an especial focus on the degradation of the allergenic milk proteins; ${\alpha}_{s1}$-casein and ${\beta}$-lactoglobulin and also to record the generation of peptides. Lipolysis of the milk fat and release of fatty acids were also under consideration. After 40 min of gastric digestion, all the ${\alpha}_s$-caseins were digested completely while ${\beta}$-lactoglobulin remained intact. During 120 min of duodenal digestion ${\beta}$-lactoglobulin was reduced, however, still some intact ${\beta}$-lactoglobulin was observed. The highest number of peptides was identified from ${\beta}$-casein and almost all the peptides from ${\kappa}$-casein and ${\beta}$-lactoglobulin were identified from the gastric and duodenal samples, respectively. No lipolysis was observed in the gastric phase of digestion. After 120 min of duodenal digestion, milk fat showed 48% lipolysis. Medium (C10:0 to C16:0) and long (${\geq}C17:0$) chain fatty acids showed 6% to 19% less lipolysis than the short (C6:0 to C8:0) chain fatty acids. Among the unsaturated fatty acids $C18:1{\sum}others$ showed highest lipolysis (81%) which was more than three times of $C18:2{\sum}all$ and all other unsaturated fatty acids showed lipolysis ranging from 32% to 38%. The overall digestion of Bangladeshi Red Cattle milk was more or less similar to the digestion of Nordic bovine milk (Norwegian Red Cattle).

Anti-inflammatory Effects of Phytochemicals Having Michael Addition Acceptors by the Modulation of Toll-like Receptor Signaling Pathways (Michael addition acceptor 그룹을 가지고 있는 phytochemicals의 toll-like receptor 신호전달체계 조절을 통한 항염증 효과)

  • Youn, Hyung-Sun
    • Korean Journal of Food Science and Technology
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    • v.41 no.5
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    • pp.477-482
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    • 2009
  • Toll-like receptors (TLRs) play a critical role in the induction of innate immune responses that are essential for host defense against invading microbial pathogens. In general, TLRs have two major downstream signaling pathways, namely MyD88- and TRIF-dependent pathways, leading to the activation of nuclear factor-${\kappa}B$ (NF-${\kappa}B$) and interferon regulatory factor 3 (IRF3) and the expression of inflammatory mediators. TLR4 dimerization is required for the activation of downstream signaling pathways and may be one of the first lines of regulation in activating TLR-mediated signaling pathways. In this paper, the molecular targets of curcumin, 6-shogaol, and cinnamaldehyde in TLR signaling pathways will be discussed. Curcumin, 6-shogaol, and cinnamaldehyde with ${\alpha},{\beta}$-unsaturated carbonyl groups inhibit the dimerization of TLR4 induced by lipopolysaccharide, resulting in the downregulation of NF-${\kappa}B$ and IRF3. These results suggest that phytochemicals with the structural motif conferring Michael addition inhibit TLR4 dimerization, suggesting a novel mechanism for the anti-inflammatory activity of phytochemicals.