The behaviour of qinghaosu (artemisinin) in the presence of non-heme iron(II) and (III)
作者:Richard K. Haynes、Simone C. Vonwiller
DOI:10.1016/0040-4039(95)02142-6
日期:1996.1
In aprotic solvents with FeCl3, cysteine or FeCl2, qinghaosu (artemisinin) undergoes rearrangement to give the tetrahydrofuran acetate, 4-hydroxydesoxoqinghoasu or the enol lactone as the major product depending on the amount of catalyst used and the polarity of the reaction medium.
The role of the 12-carboxylic acid group in the spontaneous autoxidation of dihydroartemisinic acid
作者:Lai-King Sy、Geoffrey D Brown
DOI:10.1016/s0040-4020(01)01192-9
日期:2002.1
Three of the four steps in the slow spontaneous autoxidation of dihydroartemisinic acid to artemisinin ('ene-type' reaction of molecular oxygen with the Delta(4.5) double bond, Hock cleavage of the resulting tertiary allylic hydroperoxide, oxygenation of the enol product from Hock cleavage and cyclization of the resulting vicinal hydroperoxyl-aldehyde to the 1,2,4-trioxane system of artemisinin) are shown to be assisted by the proximity of the 12-carboxylic acid functional group in dihydroartemisinic acid to the functional groups participating in these reactions. (C) 2002 Elsevier Science Ltd. All rights reserved.
Syntheses of dihydroartemisinic acid and dihydro-epi-deoxyarteannuin B incorporating a stable isotope label at the 15-position for studies into the biosynthesis of artemisinin
作者:Lai-King Sy、Nian-Yong Zhu、Geoffrey D Brown
DOI:10.1016/s0040-4020(01)00711-6
日期:2001.10
[15-13C2H3]-Dihydroartemisinic acid (3a) and [15-13CH3]-dihydro-epi-deoxyarteannuin B (7b), intended for evaluation in vivo as biosynthetic precursors to artemisinin, have been obtained from a reconstructive synthesis. The decalenone acid 8 from acid degradation of artemisinin (1) serves as a common intermediate: following addition of labeled methyl Grignard reagent to 8, either labeled precursor can
[15- 13 c ^ 2 ^ h 3 ] -二氢青蒿酸(图3a)和[15- 13 CH 3 ]二氢外延-deoxyarteannuin B(图7b),用于评估在体内生物合成的前体青蒿素,已经从获得重建综合。青蒿素(1)的酸降解产生的十氢萘酮酸8用作常见的中间体:将标记的甲基格氏试剂添加到8中,可以通过改变所采用的后处理条件以高收率制备任何标记的前体。结果表明,两种化合物在储存时都易于自氧化,当用这些标记的前体在旨在确定青蒿中青蒿素生物合成途径的饲养实验中使用此类标记的前体时,这种氧化和随后的重排反应的产物可能与真正的代谢物混淆。
The behaviour of qinghaosu (artemisinin) in the presence of heme iron(II) and (III)
作者:Richard K. Haynes、Simone C. Vonwiller
DOI:10.1016/0040-4039(95)02141-8
日期:1996.1
With hemin [chloroprotoporphyrin IX iron(III)] or hemin/cysteine in aqueous MeCN, oxygen loss from the peroxide bridge of qinghaosu takes place to give a precursor to desoxoqinghaosu, a known malaria-inactive metabolite, in low yield. Ring-opened forms of qinghaosu such as the free hydroperoxide or peroxyhemiacetal react with hemin and heme to give predominantly the diketone resulting from oxygen loss