Formamide?
Joong-Yeon Bae
I'd like to know whether formamide(HCONH2) is basic or nucleophililc.
I want to use formamide as reaction medium. However, my compount is
electrophilic, that is, easily react with nucleophile or basic material.
Dose the amino group in formamide act as nucleophile or base?
Anybody who know the answer, help me!
Thank you!
David Hemmings
<361AF003...@matlb.kjist.ac.kr>...
Due to resonance the nitrogens basicity and nucleophilicity are muted.
Formamides can be made to react with various compounds including
alkenes, acetals, and aromatic rings. Mainly dependent on the presence
of a free radical initiator, although POCl3 (Vilsmeyer) can be used.
But they react at the carbon not at the nitrogen.
Think of DMF, should find a lot of literature on this, Paquettes
'organic reagents in org. synth. ?'
or dic. org. chem.
i think the only real problem is using with a fairly strong acid -->
production of HCN i believe.
So it really depends on what you have, what the reagents are, and the
reaction conditions.
HTH
DH
Gabriel Tojo
>
> Joong-Yeon Bae <jy...@matlb.kjist.ac.kr> wrote in article
> <361AF003...@matlb.kjist.ac.kr>...
> > Hi!
> >
> > I'd like to know whether formamide(HCONH2) is basic or nucleophililc.
> > I want to use formamide as reaction medium. However, my compount is
> > electrophilic, that is, easily react with nucleophile or basic
> material.
> >
> > Dose the amino group in formamide act as nucleophile or base?
Formamide, as most (all?) organic compounds is simultaneously basic,
acid, nucleophilic and electrophilic. It depends on its reaction
partner.
It is basic because it may be protonated on the oxygen, and less readely
on the nitrogen.
It is acid because it may deliver a proton from the nitrogen.
It is nucleophylic because the oxygen, and less readely the nitrogen may
attack an electron-poor center. This is easier if you previously form
the corresponding anion.
It is electrophilic because it may be attacked by a nucleophile on the
carbon atom.
It may react with your electrophilic compound if it is electrophilic
enough.
Gabriel Tojo
David Hemmings
<361C78...@uscmail.usc.es>...
Could you furnish some examples, and also doubly subst N as well , i
covered the nucleophilic attack on carbon already. Conjugation clouds
the issue somewhat.
I am not disagreeing just interested for some examples.
As a protecting group on a bicyclic nitrogen (like tropanes)
Benzyloxycarbonyl is remarkably resilient to many forms of attack. It
will be cleaved off by hydrogenation (although not very readily),
resist hydride attack at low temperature, usual deprotection is by TMSI
which attacks the carbon (carbonyl) to make silyl etherate which
breaksdown leaving deprotected nitrogen.
Gabriel Tojo
...
> >
> > Formamide, as most (all?) organic compounds is simultaneously basic,
> > acid, nucleophilic and electrophilic. It depends on its reaction
> > partner.
> >
> > It is basic because it may be protonated on the oxygen, and less
> readely
> > on the nitrogen.
> >
> > It is acid because it may deliver a proton from the nitrogen.
> >
> > It is nucleophylic because the oxygen, and less readely the nitrogen
> may
> > attack an electron-poor center. This is easier if you previously form
>
> > the corresponding anion.
> >
> > It is electrophilic because it may be attacked by a nucleophile on
> the
> > carbon atom.
> >
> > It may react with your electrophilic compound if it is electrophilic
> > enough.
> >
> > Gabriel Tojo
>
> Could you furnish some examples, and also doubly subst N as well , i
> covered the nucleophilic attack on carbon already. Conjugation clouds
> the issue somewhat.
Formamide as an acid:
Deprotonation of N with LDA
Formamide as a base:
Protonation on O with conc.H2SO4
Formamide as electrophyle
Hydrolisis with base
Formamide as nucleophyle
Acylation with acid chloride
>
> I am not disagreeing just interested for some examples.
>
> As a protecting group on a bicyclic nitrogen (like tropanes)
> Benzyloxycarbonyl is remarkably resilient to many forms of attack. It
> will be cleaved off by hydrogenation (although not very readily),
> resist hydride attack at low temperature, usual deprotection is by TMSI
> which attacks the carbon (carbonyl) to make silyl etherate which
> breaksdown leaving deprotected nitrogen.
Due to conjugation with carbonyl, the nitrogen of formamide is very weakly
basic and nucleophylic, much less than the nitrogen of amines. That means
that unless you are working with very strong acids or electrophyles,
formamide would not pose any problem. In fact, a derivative thereof, DMF,
is a very common solvent that is inert to most reagents, with the notable
exception of organometallics and Lewis acids.
An Nbenzyloxycarbonylation of an amine should be possible using DMF as
solvent.
Please, could you tell us exactly the nature of your problem?
Most respectfully
Gabriel Tojo
David Hemmings
Gabriel Tojo <qoga...@uscmail.usc.es> wrote in article
\Formamide as an acid:
\Formamide as a base:
\Formamide as electrophyle
\Hydrolisis with base
\Formamide as nucleophyle
\Acylation with acid chloride
I believe i suggested this.
\that unless you are working with very strong acids or electrophyles,
\formamide would not pose any problem. In fact, a derivative thereof,
DMF,
\is a very common solvent that is inert to most reagents, with the
notable
\exception of organometallics and Lewis acids.
\An Nbenzyloxycarbonylation of an amine should be possible using DMF
as
\solvent.
The use of neat chloride works just fine though.
\Please, could you tell us exactly the nature of your problem?
I may or maynot have problems, but they are not chemistry related. I
was originally responding to another post. And i also asked for the
person to verify for what they need formamide for.
\Most respectfully
\Gabriel Tojo
----------
Gabriel Tojo
...
>
> \Please, could you tell us exactly the nature of your problem?
>
> I may or maynot have problems, but they are not chemistry related. I
> was originally responding to another post. And i also asked for the
> person to verify for what they need formamide for.
Sorry, David,
At this point I am completely lost and I have no idea about what we are
talking about.
I wish you to solve your non chemistry related problems.
Cheers
Gabriel Tojo