- Divergent total synthesis of the lycopodium alkaloids huperzine A, huperzine B, and huperzine U
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Huperzine A, huperzine B, and huperzine U are congeners isolated from the Chinese herb Huperzia serrata (=Lycopodium serratum) in minuscule amounts. The most efficient total synthesis of huperzine A, the first asymmetric total syntheses of huperzine B, and the first total synthesis of huperzine U have been achieved efficiently in overall yields of 17%, 10%, and 9%, respectively, each spanning 10-13 steps from (R)-pulegone. The featured steps include palladium-catalyzed Buchwald-Hartwig coupling and Heck cyclization reactions and an Ir-catalyzed olefin isomerization reaction. This work has established the absolute configurations of huperzine B and huperzine U and revealed that natural huperzine A, huperzine B, and huperzine U possess the same set of absolute stereochemistries, thus providing support for the potential role of huperzine B and huperzine U in the biosynthesis of huperzine A.
- Ding, Rui,Fu, Jian-Guo,Xu, Guang-Qiang,Sun, Bing-Feng,Lin, Guo-Qiang
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p. 240 - 250
(2014/01/17)
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- Huperzines and analogs
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The invention relates to compounds of the formulas STR1 wherein R1, R2 and R3 independently are hydrogen or lower alkyl, and the dotted ( . . . ) line is an optional double bond, and their pharmaceutically acceptable acid addition salts. The compounds of formulas I, II and III possess marked anticholinesterase activity and are useful as analeptic agents and as agents for the treatment of senile dementia and myasthenia gravis.
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