Pyranoindolizine derivatives and preparation process thereof
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(2008/06/13)
Certain pyrano (3,4-f)-indolizine derivatives
A pyranoindolizine derivative represented by the following general formula (I): STR1 wherein R means a hydrogen atom or hydroxyl group and Q denotes >C=O or STR2 with a proviso that Q is other than >C=O when R is a hydrogen atom. Its preparation process is also described.
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(2008/06/13)
Plant antitumor agents. 28. Resolution of a key tricyclic synthon, 5'(RS)-1,5-dioxo-5'-ethyl-5'-hydroxy-2'H,5'H,6'H,H-6'-oxopyrano[3',4' f]Δ6,8-tetrahydroindolizine: Total synthesis and antitumor activity of 20(S)- and 20(R)-camptothecin
The resolution of the tricyclic ketone (3a + 3b) by the separation of diastereomeric adducts 4a and 4c of the precursor ketal 5 is described. The regenerated enantiomers 3a and 3b of 100% optical purity represent the key intermediates from which 20(R)-camptothecin (1a) and 20(S)-camptothecin (1b), respectively, have been prepared. The 20R analogue 1a was 10-100 times less active than the natural 20(S)-camptothecin (1b) in 9KB and 9PS cytotoxicity assays and almost inactive in in vivo L-1210 leukemia tests as compared to the highly potent and active natural compound 1b.
Wani,Nicholas,Wall
p. 2317 - 2319
(2007/10/02)
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