ipso-vs. tele-Nucleophilic substitution by piperidine on isocolchicides and colchicides bearing an α-leaving group
摘要:
Product studies of the reactions of piperidine with colchicides carrying a C-10 nucleofugic group show that only ipso substitution occurs. For isocolchicides carrying an X nucleofugic group at C-9, similar behaviour was observed for X = F, OTs or OMe, while for X = SMe, SOMe or Cl tele substitution (at C-ll) competes with ipso substitution. These results together with the observation that the reaction rates for the two series are similar, may be useful in guiding the refunctionalization of similar compounds.
Synthesis and tubulin binding of novel C-10 analogs of colchicine
作者:Marianne E. Staretz、Susan Bane Hastie
DOI:10.1021/jm00058a013
日期:1993.3
10-fluoro-10-demethoxycolchicine (9) without concomitant formation of ring contraction products. Compound 9 is prepared by reaction of (diethylamino)sulfurtrifluoride with colchiceine. Unlike most reactions of colchiceine, the colchicine rather than the isocolchicine regiosiomer is the predominant product of this reaction. It was found that modification of the C-10 substituent of colchicine had a relatively
ipso-vs. tele-Nucleophilic substitution by piperidine on isocolchicides and colchicides bearing an α-leaving group
作者:Marino Cavazza、Francesco Pietra
DOI:10.1039/p19950002657
日期:——
Product studies of the reactions of piperidine with colchicides carrying a C-10 nucleofugic group show that only ipso substitution occurs. For isocolchicides carrying an X nucleofugic group at C-9, similar behaviour was observed for X = F, OTs or OMe, while for X = SMe, SOMe or Cl tele substitution (at C-ll) competes with ipso substitution. These results together with the observation that the reaction rates for the two series are similar, may be useful in guiding the refunctionalization of similar compounds.