The alkaloid deoxyharringtonine and its precursor 3'-O-(5-methyl-2-oxohexanoyl)-cephalotaxine were synthesized according to the following preferred series of reactions: Ethyl t-butyl oxalate + 1-lithio-3-methylbut-1-yne .fwdarw. t-butyl 5-methyl-2-oxohex-3-ynoate .fwdarw. t-butyl 5-methyl-2-oxohexanoate .sup.-trifluoroacetic acid 5-methyl-2-oxohexanoic acid .sup.(COCl).sbsp.2 5-methyl-2-oxohexanoyl chloride .sup.cephalotaxine 3'-O-(5-methyl-2-oxohexanoyl)-cephalotaxine .sup.lithio methyl acetate deoxyharringtonine.
利用以下优选反应序列合成了
生物碱去氧哈林汀及其前体3'-O-(5-甲基-2-氧代己酰基)-头孢乌斯碱:
乙酰丙酮乙酯 + 1-
锂-3-甲基丁-1-炔 .fwdarw. 叔丁基 5-甲基-2-氧代己-3-炔酸叔丁酯 .fwdarw. 叔丁基 5-甲基-
2-氧代己酸 .sup.-
三氟乙酸 5-甲基-
2-氧代己酸 .sup.(COCl).sbsp.2 5-甲基-2-氧代
己酰氯 .sup.头孢乌斯碱 3'-O-(5-甲基-2-氧代己酰基)-头孢乌斯碱 .sup.
锂甲酸甲酯 去氧哈林汀。