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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
3
|
| pubmed:dateCreated |
1990-4-6
|
| pubmed:abstractText |
The total synthesis of the pentacyclic camptothecin analogues 3 and 4 in 11 steps from p-tolualdehyde is described. The overall shape of compound 3 is the same as that of potent, naturally occurring camptothecin (1a). Despite the near spatial identity of 3 and 1b (racemic, (20RS)-camptothecin) from a three-dimensional standpoint, the 9KB and 9PS cytotoxicity assays indicate at least a 40-60-fold decrease in activity of 3 compared to that of 1b, and the isomer 4 was inactive. Similarly, studies of the inhibition of topoisomerase I activity indicated only slight activity for 3 and no activity for 4. It is evident that the pyridone ring D is essential for antitumor activity. Three E ring modified analogues of camptothecin, 2d-f, are described in which the net change is replacement of O by N in ring E. Compared to (20S)-camptothecin (1a) or (20RS)-camptothecin (1b), the ring E modified analogues 2d-f display little or no cytotoxic activity, greatly reduced effect on the inhibition of topoisomerase I, and total loss of life prolongation in the in vivo L-1210 mouse leukemia assay, indicative of the highly restricted structural and electronic requirements of ring E for biological activity in camptothecin.
|
| pubmed:grant | |
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:month |
Mar
|
| pubmed:issn |
0022-2623
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
33
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
972-8
|
| pubmed:dateRevised |
2010-11-18
|
| pubmed:meshHeading | |
| pubmed:year |
1990
|
| pubmed:articleTitle |
Plant antitumor agents. 29. Synthesis and biological activity of ring D and ring E modified analogues of camptothecin.
|
| pubmed:affiliation |
Research Triangle Institute, Research Triangle Park, North Carolina 27709.
|
| pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.
|