From: Jonas Nilsson (jonni$##$ifm.liu.se)
Date: Wed May 02 2001 - 09:54:20 EDT
I'm having trouble converting the dimethyl 1R,2R-cyclopropanedicarboxylate
to the methyl 1R-amino-2R-cyclopropanecarboxylate.
|> = cyclopropane
MeOOC-|>-COOMe -> MeOOC-|>-COOH This works fine!
MeOOC-|>-COOH -> MeOOC-|>-CNO (Using DPPA / Et3N) No
MeOOC-|>-CNO -> MeOOC-|>-NHCOOR Works nice with any
alcohol I've tried
Now to the hard part:
MeOOC-|>-CNO -> MeOOC-|>-NH3+ (Using HCl(aq or MeOH))
MeOOC-|>-CNO -> MeOOC-|>-NH2 (Using H2O) Doesn't work
MeOOC-|>-NHCOOR -> MeOOC-|>-NH2 (Different deprotection
strategies) Doesn't work
I've used different carbamates (FMOC, BOC, CBZ, Me, Ph) and different
deprotection strategies, but all seem to fail. It's hard for me to conclude
what happens, but I think the ring breaks up.
I've searched the crossfire database for reactions, and there are a lot of
compounds with a 1-carbonyl-2-(NH-prot.group.) substituted ring. There are
also a lot of reactions invovling 1-(free amine) and a 2-aryl/alkyl
substituent pattern. But I get no hits with 1-(free amine) 2-(electron
withdrawing group). Are these compounds impossible to make or what?
I later on need to derivitize both amine and carboxylate as amide bonds.
Will I have to do something like this do you think?
MeOOC-|>-NHCOOR (DIBAL)-> HOCH2-|>-NHCOOR (Deprot, coupling)->
HOCH2-|>-NHCOR' (ox., coupling) -> R''NOC-|>-NHCOR'
Any other suggestions?
IFM, Dept. of Chemistry
581 83 Linkoping
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