- An Efficient Enantioselective Synthesis of Indicine N-Oxide, an Antitumor Pyrrolizidine Alkaloid
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Indicine N-oxide (1), a pyrrolizidine alkaloid potentially useful for an anticancer drug was synthesized in the natural form through regioselective coupling of (+)-retronecine (2) and the protected necic acids 16a and 16b, the latter being efficiently prepared from the optically pure lactone 5.
- Ogawa, Takeshi,Niwa, Haruki,Yamada, Kiyoyuki
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p. 1571 - 1578
(2007/10/02)
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- Synthesis of pyrrolizidine alkaloids indicine, intermedine, lycopsamine, and analogues and their N-oxides. Potential antitumor agents
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(-)- and (+)-trachelanthic and (-)- and (+)-viridifloric acids were synthesized and their isopropylidene derivatives were regiospecifically coupled, at C-9, with (-)-retronecine (2) obtained by hydrolysis of monocrotaline (1), isolated from Crotalaria spectabilis. Hydrolysis, followed by oxidation, led to the N-oxides of indicine (7), intermedine (13), lycopsamine (15), and the new nonnatural product 16, respectively. Each of these analogues was screened in the P388 lymphocytic leukemia system at the same time as indicine N-oxide, and the results were compared. Other related analogues were prepared and similarly screened and the results compared with those from indicine N-oxide.
- Zalkow,Glinski,Gelbaum,Fleischmann,McGowan,Gordon
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p. 687 - 694
(2007/10/02)
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