Re: ORGLIST: S-alkylation of 2-thiouracil

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From: by way of Joao Aires de Sousa (lemcoff$##$post.tau.ac.il)
Date: Thu Mar 20 1997 - 01:26:14 EST


One possibility is the formation of an allyl cation by electrocyclic ring
opening of the cyclopropyl cation then you would get an allyl derivative
instead of the cyclopropyl derivative you were looking for. The
cyclopropyl cation is not formed readily but with a good leaving group
such as iodide and depending on reaction conditions it might be formed,
the rearrangement to allyl cation is then very fast. Hope it might help
you, Gabriel

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On Wed, 19 Mar 1997, Gianluca Sbardella wrote:

> On Tue, 18 Mar 1997 alihoyer$##$inet.uni-c.dk wrote:
>
> > Dear Gianluca,
> >
> > What was the product of the reaction?
> >
>
> As I wrote in the original message, using many different alkyl- and
> cycloalkylhalides the product was a 2-alkyl- or
> 2-cycloalkylthio-4-oxopirimidine (that's to say the tautomer of
> 2-thiouracil in which the hydrogen on the sulfur atom is substituted by an
> alkyl or cycloalkyl group).
> With cyclopropyl iodide the reation doesn't occur...
>
> Gianluca "Blue Merlin" Sbardella
>
> >
> > Dear colleagues,
> > > I've synthesized many 6-substituted-2-alkylthio-4-oxo-pyrimidines by
> > > S-alkylation of 2-thiouracils with alkyl halides and potassium carbonate
> > > in DMF, but when I tried to introduce the cyclopropyl group in the same
> > > way(i.e. with cyclopropyl iodide) I failed. Do you have any suggestion?
> > > I'll summarize to the list the answers I'll get.
> > > Thank you in advance,
> > >
> > > Gianluca " Blue Merlin" Sbardella
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> >
> >
>
> ***************************************************************
> * *
> * Dr. Gianluca Sbardella E-mail: r.ragno$##$caspur.it *
> * Dip.Studi Farmaceutici *
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__________________

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