青蒿素生物合成的研究III: 青蒿素和青蒿素B生物合成中的关键性中间体-青蒿素

以[15-^3H]青蒿酸为前体用青蒿匀聚浆体进行青蒿素和青蒿素B的生物合成.实验结果表明, 在青蒿植物由MVA生物合成青蒿素和青蒿素B的途径中, 青蒿酸是关键性中间体.     

Chemical transformations of arteannuin B

Using arteannuin B (2) isolated from Artemisia annua L.,a number of chemical transformations have been carried out, i.e., catalytic hydrogenation of 2 to give a mixture of 5, 6 and 7, reaction of 6 with boron trifluoride etherate to give 8 and 9, saponification of 6 with potassium hydroxide and deoxygenation of 2, 6 and 7 with iron pentacarbonyl to give 18, 4 and 3, respectively.     

青蒿素的二维核磁共振研究

报导了采用二维核磁共振技术研究青蒿素的核磁氢谱和碳谱的谱线归属,以今后为^1^3C中间体的生物转化产物提供鉴定的基础.     

青蒿乙素的化学转化

本文报道青蒿乙素(2)的若干化学转化,如:青蒿乙素的催化氢化得到三个化合物5,6,7.6与三氟化硼-乙醚配合物反应生成8和9.6用硷水解以及2,6,7分别与五羰基铁进行脱氧反应,得到相应的化合物18,3和4。     

青蒿素及其一类物的结构和合成的研究 XXII: 青蒿丁素的区域选择性合成

本文报导了从青蒿酸所得的烯醇硅醚化合物, 经OsO4的区域选择性羟基化和环合,得青蒿丁素的合成路线.     

青蒿素及其一类物的结构和合成XI.青蒿乙素及异青蒿乙素的立体选择性合成

本文报道以青蒿酸为原料合成青蒿乙素(1)及其6β-异构体4. 并根据红外光谱丶核磁共振谱丶圆二色散以及有关的化学反应确定了究们的结构和构型.     

Studies on the biosynthesis of arteannuin. IV. The biosynthesis of arteanniuin and arteannuin B by the leaf homogenate of Artemisia annua L.

Arteannuic acid and (-)11R,13-dihydroarteannuic acid are the key intermediates in the biosynthesis of arteannuin by the leaf homogenate of Artemisia annua L., and arteannuic acid and epoxyarteannuic acid are the intermediates of arteannuin B. and epoxyarteannuic acid can not be transformed into arteannuin by the homogenate.     

青蒿素及其一类物结构和合成的研究 X.从青蒿酸立体控制合成青蒿素和脱氧青蒿素

Arteannuin (1), a new sesquiterpene lactone containing a peroxide group, is the antimalarial active principle isolated from Artemisia annua L. Deoxyarteannuin (2) occurs in the same plant and was isolated as a metabolite from the urine of patients treated with arteannuin. We now report a stereocontrolled synthesis of these two naturally occurring sesquiterpene lactones starting from arteannuic acid (5) by the reaction sequence as shown in Scheme 2 (see Chinese Text). Irradiation of the methanolic solution of the key intermediate 3 in the resence of oxygen and a sensitizer (Rose Bangal) with 200 W high pressure mercury lamp followed by acid treatment gave 1 in 28% yield (2 steps), m.p. 151-153`c,     

青蒿素及其一类物的结构和合成XVI.青蒿戊素的合成和α-环氧青蒿酸甲酯环氧的开环反应

β-环氧青蒿酸甲酯(25)经甲酸处理得反式双竖键开环产物(26),经水解和内酯化得青蒿戊素(1),α-环氧青蒿酸甲酯(5)或叔丁酯(18)及α-环氧双氢青蒿酸甲酯(12a,b)与甲酸反应未生成反式双竖键开环产物,并对其反应机理作了讨论。     

Stereoselective reduction of arteannuin B and its chemical transformations

Absolute stereochemistry of dihydroarteannuin B 5 obtained by the reduction of arteannuin B 3 with Ni₂B, NaBH₄ or CdCl₂-Mg-MeOH-H₂O has been established by 2D NMR and single crystal X-ray diffraction studies. Some experiments aimed at the synthesis of dihydrodeoxyarteannuin B [C-4, 5 double bond isomer of 11] are also discussed.     

Biomimetic synthesis of arteannuin h and the 3,2-rearrangement of allylic hydroperoxides

The acyl endoperoxide arteannuin H, recently reported as a novel natural product from Artemtsia annua, has been obtained in two steps from the photooxidation of dihydroartemisinic acid, thereby confirming biogenetic speculation regarding its derivation from a secondary allylic hydroperoxide. The little studied 3,2-rearrangement reaction of such allylic hydroperoxides is also discussed.