Re: ORGLIST: 1-Carboxy-2-amino-cyclopropanes.

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From: kalbe farma (super_visser$##$yahoo.com)
Date: Thu May 03 2001 - 05:36:35 EDT




--- Jonas Nilsson <jonni$##$ifm.liu.se> wrote:
> Dear Readers.
> 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
> problems here!
> 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))
> Doesn't work
> 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?
> Please advise.
> /jN
> --
>
> ----------///|||+X+|||\\\------------
> Jonas Nilsson
> IFM, Dept. of Chemistry
> Linkoping University
> 581 83 Linkoping
> Sweden
>
> phone: +46-13-285690
> fax: +46-13-281399
> ----------\\\|||+X+|||///------------
> .>>>>>>>>>>>>>>>><<<<<<<<<<<<>>>>>>>>>>><<

Hallo Jonas,
I wish this will help you to solve your problem.
probably you should reduce your product ( carbamates)
with certain reducer as H2 in presence of Pd/C or
NaBH4 or LiAlH4.


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