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青蒿甲素(1)与抗疟有效成分青蒿素(2)共存于植物青蒿之中,它是一个新型的失碳倍半萜内酯,其结构已经测定,本文报道它的合成. 青蒿酸甲酯(3)用间氯过苯甲酸氧化,得4α,5α-环氧青蒿酸甲酯(4).4在二氯甲烷-吡啶中进行臭氧化,得α-酮酸酯(5),产率88％.5用碱性过氧化氢氧化降解,得羟基内酯(6),产率92％.6用POCl_3-吡啶脱水,即得1,m.p.151～153℃,[α]_~(10)-40°(c 0.57,CHCl_3),与天然品的混合熔点不降低,其IR、~1H NMR、MS、TLC R_1值和GC亦完全一致. 在推定6的结构时,我们曾将5的碱性过氧化氢氧化反应分步进行.先用碱水解,结果得
Artemisinin (1) and artemisinin (2), the anti-malarial active ingredient, coexist in the plant Artemisia annua. It is a novel carbon-loss sesquiterpenoid lactone whose structure has been determined and its synthesis reported here. Artemisinic acid methyl ester (3) was oxidized with meta-chloroperbenzoic acid to give 4α, 5α-epoxy artenic acid methyl ester (4) .4 Ozonation in dichloromethane-pyridine gave α-keto ester (5), the yield of 88% .5 oxidized with alkaline hydrogen peroxide degradation, hydroxyl lactone (6), the yield of 92% .6 Dehydration with POCl_3- pyridine, that is 1, mp151 ~ 153 ° C, α] _ ~ (10) -40 ° (c 0.57, CHCl_3), and the melting point of the mixture with natural products does not decrease, IR, ~ 1H NMR, MS, TLC R_1 values and GC also exactly the same. , We have 5 alkaline hydrogen peroxide oxidation step by step first with alkaline hydrolysis, the result