• Title/Summary/Keyword: conjugate addition

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Organocatalytic Enantioselective Michael Addition of α-Nitroacetate to α,β-Unsaturated Enones: A Route to Chiral γ-Nitro Ketones and δ-Keto Esters

  • Moon, Hyoung-Wook;Kim, Dae-Young
    • Bulletin of the Korean Chemical Society
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    • v.32 no.1
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    • pp.291-295
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    • 2011

  • The catalytic enantioselective conjugate addition reaction of $\alpha$-nitroacetate to $\alpha,\beta$-unsaturated enones promoted by chiral bifunctional organocatalysts is described. The treatment of $\alpha$-nitroacetate to $\alpha,\beta$-unsaturated enones afforded the corresponding Michael adducts with high enantioselectivity. The conjugate addition adducts are easily converted to chiral $\gamma$-nitro ketones and $\delta$-keto esters.

  • https://doi.org/10.5012/bkcs.2011.32.1.291 인용 PDF KSCI

Synthesis of an Amphiphilic Poly(${\gamma}$-Glutamic Acid)-Cholesterol Conjugate and Its Application as an Artificial Chaperone

  • Lee, Eun-Hye;Kamigaito, Yoshiki;Tsujimoto, Takashi;Uyama, Hiroshi;Sung, Moon-Hee
    • Journal of Microbiology and Biotechnology
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    • v.20 no.10
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    • pp.1424-1429
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    • 2010

  • A poly(${\gamma}$-glutamic acid) (${\gamma}$PGA)-cholesterol conjugate was synthesized and its properties were then evaluated. The conjugate exhibited an amphiphilic nature derived from the hydrophilic ${\gamma}$PGA backbone and the hydrophobic cholesterol side chain. The conjugate spontaneously formed nanoparticles, becoming an aqueous solution when at low concentrations, and at high concentrations the result was the formation of a physical gel. By utilizing the self-aggregating properties of the conjugate in water, an artificial chaperone was developed. A complex of protein, with the nanoparticles of the conjugate, was formed and the protein was released upon the dissociation of the nanoparticles through the addition of ${\beta}$-cyclodextrin. For denatured carbonic anhydrase, the activity was recovered in the artificial chaperone of the nanoparticle conjugate.

  • https://doi.org/10.4014/jmb.1006.06004 인용 PDF KSCI

Evaluation of Thrombolytic Effect of Streptokinase-Dextran Conjugate in a Rat Model of Arterial Thrombosis (흰쥐의 대퇴동맥 혈전 모델에서의 스트렙토키나제-덱스트란 포합체의 혈전용해효과의 평가)

  • Kim, Yang-Woo;Kim, Dong-Chool
    • Journal of Pharmaceutical Investigation
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    • v.29 no.3
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    • pp.211-216
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    • 1999

  • To evaluate the thrombolytic activity of streptokinase-dextran conjugate, a rat model of arterial thrombosis was used. Briefly, the femoral artery was exposed and a filter paper saturated with 70% $FeCl_3$ solution was placed around the femoral artery in order to stop the blood flow. Six minutes after the stop of the blood flow in the femoral artery, streptokinase $(10000{\sim}30000\;units\;per\;rat)$ or streptokinase-dextran conjugate $(5000{\sim}17000\;units\;per\;rat)$ was administered by i.v. bolus injection through the femoral vein. Then the blood flow in the femoral artery was monitored using a Doppler laser flow meter. The i.v. bolus administration of streptokinase could not restore the blood flow in the femoral artery in the dose range of $10000{\sim}30000$ units per rat. The i.v. bolus administration of streptokinase-dextran conjugate could restore the blood flow in the femoral artery in the dose range of $5000{\sim}17000$ units per rat. A good correlation between the dose of streptokinase-dextran conjugate and the total thrombolytic effect was observed. In addition, the lag time between the injection of streptokinase-dextran conjugate and the restoring of the blood flow was decreased as the i.v. dose of streptokinase dextran conjugate increased. These results show the superior beneficial effect of streptokinase-dextran conjugate compared with the unconjugated streptokinase with respect to the elongation of thrombolytic activity, the administration method (single injection versus continuous infusion), and the reduced dose necessary for a equivalent thrombolytic effect.

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