Camptotheca acuminate

Camptothecin, an alkaloid isolated from a Chinese tree Camptotheca acuminate), is a potent cytotoxic agent, acting by the inhibition of DNA topoisomerase I. Derivatives that are fluorinated on the aromatic ring A have been studied, leading to two drug candidates for cancer therapies (Figure 8.7) ° exatecan is in Phase IB development,and diflomotecan is an E-homocamptothecin currently in Phase II trials for several solid cancers. 

Camptothecin (CPT) - a compound isolated from the bark, leaves and fruit of Camptotheca acuminate (Wall M. E. et al., J. Am. Chem. Soc. 88, 3888,... 

The parent camptothecin alkaloid, isolated from bark of Camptotheca acuminate, has antitumor activity, but its limited water solubility necessitated delivery as ... 

TiifoUn Camptotheca acuminate Alternaria altemata Epicoccum nigrum Pestalotia guepinii Drechslera sp Fusarium avenaceum Li et al. (2005)... 

Li S, Zhang Z, Cain A et al (2005) Antifungal activity of camptothecin, trifolin, and hyperoside isolated from Camptotheca acuminate. J Agile Food Chem 53 32-37 Li L, Ge H, Seeram NP (2009) Identification and bioactivities of resveratrol oligomers and flavonoids from Carex folliculata seeds. J Agile Food Chem 57 7282-7287 Lim Y-H, Kim I-H, Seo J-J (2007) In vitro activity of kaempferol isolated from the Impatiens bal-samina alone and in combination with erythromycin or clindamycin against Propionibacterium acnes. J Microbiol 45 473-477... 

The tetracyclic A/B/C/D ring core of (205)-camptothecin, one of the most potent antitumor natural products isolated from Camptotheca acuminate, was prepared by a combined directed ortho metallation/cross-coupling strategy. Snieckus showed that 2-bromo-6-methoxypyridine (152) could be sequentially treated with ter/-butyllithium (2 equiv) at -78 °C and anhydrous zinc bromide. The resulting organozinc species was then subjected to palladium-catalyzed cross-coupling reaction with triflate 153 to afford the biaryl 154, a precursor to the tetracyclic A/B/C/D ring core 155. 

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