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1-溴-4-氧戊烷的乙二醇缩酮(1)的格氏试剂,与草酸二乙酯反应,得2,6-二氧-6-乙二醇缩酮庚酸乙酯(2).2经相应的钠盐3、酰氯4再转化成α-酮酰基三尖杉碱(5).5经 Reformatsky 反应,酸性水解后与碘甲烷的格氏试剂反应.所得产品经 pH 梯度萃取并结合氧化铝干柱层析纯化,得到高三尖杉酯碱及其差向异构体的混合物8.然后制成苦味酸盐,经分级结晶,再分别转化成游离碱8a 及8b.8a 的~1HNMR,MS,IR(film).和 TLC 与天然高三尖杉酯碱完全一致.8b 的 MS 和IR 与8a 极为相似,但它们的~1HNMR 却有明显差异,因此可以确定它们互为差向异构体.
1-Bromo-4-oxopentane ethylene glycol ketal (1) Grignard reagent with diethyl oxalate reaction 2,6-dioxane-6-ethylene ketal heptanoate 2) .2 Re-transformed into α-ketoacylcisplatin (5) via the corresponding sodium salt 3, acid chloride 4. Reactive reaction with Grignard reagent of methyl iodide after acid hydrolysis and hydrolysis of the resulting product via pH gradient Extracted and combined with alumina dry column chromatography to obtain homoharringtonine and its epimer mixture 8. Then made picric acid salt, after fractional crystallization, and then were converted to the free base 8a and 8b.8a 1H NMR, MS, IR (film). And TLC is identical to native homoharringtonine. The MS and IR of 8b are very similar to 8a, but their 1HNMRs are significantly different, so they can be determined to be poor Isomers.