Re: ORGLIST: hydrogenation

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From: Maringanti Krishna (maringanti9$##$yahoo.com)
Date: Fri Sep 16 2005 - 12:50:11 EDT


Andrew;
The problem is with your methanol and ethanol, which might be containing either formaldehyde or acetaldehyde. You are getting a typical reductive amination product. in order to avoid this, you must purify your alcohols thoroughly or get ACS grade reagents.
We observed the formation of isopylamines when we did certain de-protections in Isopropyl alcohol. We established unequivocally that it is because of the presence of acetone, and under pressure, preferentially the reductive amination happens.
Hope this helps
Krishna

Gang Chen <oz-wizz$##$yahoo.com> wrote:
Can you hydrogenate in acetic acid instead?

GC.

--- Andrew wrote:

> I'm attempting a hydrogenation of an Z-protected
> amine with palladion on carbon under hydrogen. The
> Z-groups is coming off fine, however, if the
> reaction is performed in methanol, I'm getting the
> NMe product, similarly if in ethanol, I'm getting
> the NEt product. How do I stop this?
>
>
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