- Synthesis and antitumour activity of β-hydroxyisovalerylshikonin analogues
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A series of novel β-hydroxyisovalerylshikonin analogues bearing oxygen-containing substituents at the side-chain hydroxyl of shikonin were designed and synthesized. The cytotoxicities of these compounds were evaluated in vitro against multi-drug resistant (MDR) cell lines DU-145 and HeLa. Most compounds exhibited significant inhibitory activity on both cell lines. The structure-activity relationship showed the analogues with ether substituents displayed the most potent antitumour activity and selective cytotoxicity towards DU-145. Among the compounds with ether substituents, increasing the steric hindrance in the carbon bearing β-hydroxyl or replace the β-hydroxyl with acetoxy or methoxy would lead to the decline of cytotoxicity.
- Rao, Zhen,Liu, Xin,Zhou, Wen,Yi, Jing,Li, Shao-Shun
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p. 3934 - 3941
(2011/11/12)
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- Reduction of Substituted Δ2-Isoxazolines. Synthesis of β-Hydroxy Acid Derivatives
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Three separate methods are reported for the formation of β-hydroxy acid derivatives from readily available substituted Δ2-isoxazolines.Cycloaddition of 2,2-dimethylpropanenitrile oxide with a variety of olefins followed by reductive cleavage produces α '-tert-butyl β-hydroxy ketones.These are cleaved to β-hydroxy tert-butyl esters by Baeyer-Villiger oxidation with peroxytrifluoroacetic acid.In the second approach, α ',β-dihydroxy ketones are generated via cycloaddition of olefins with the nitrile oxide generated from 2--2-methyl-1-nitropropane followed by reductive ring opening.Standard periodic acid cleavage gives β-hydroxy acids.Finally, 3-methoxy-substituted Δ2-isoxazolines, readily available via benzenesulfonylcarbonitrile oxide-olefin cycloaddition and methoxide displacement, are directly reduced to β-hydroxy esters.
- Curran, Dennis P.,Scanga, Susan A.,Fenk, Christopher J.
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p. 3474 - 3478
(2007/10/02)
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- Research in dipropylacetic series. XII. Aliphatic ramified acids and alcohols with anticonvulsant activity
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Previous results obtained about 2 propyl pentanoic acid (dipropylacetic or DPA) have been extended to other dialkylalkanoic acids having less than 14 carbon atoms and to some of their precursors (alcohols) or derivatives (amides). The effect of lengthening the chain bonding between the carbon bearing the two alkyl chains and the functional carbon on about 50 molecules is discussed. The anticonvulsant activity's length and strength often increases when lengthening that chain.
- Taillandier,Benoit Guyod,Boucherle,et al.
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p. 453 - 462
(2007/10/05)
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