Re: ORGLIST: Deprotection of a trityl group

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From: Eric J.Leopold (ejlmp$##$earthlink.net)
Date: Thu Dec 16 2004 - 05:21:19 EST


On Dec 15, 2004, at 8:38 PM, Ken Knott wrote:

> I have having issues deprotecting a trityl group from an amine.
> According the the publsihed papers the deprotection should occur
> easily with an acidic media. I have tried HCl, HBr, triflouroacetic
> acid, and others. Suffice to say the deprotection does not occur.
>
> I have also tried sodium in methanol based on a paper. This made a
> mess and did not work.
>
> Lastly I have tried a dehydrogenation with Pd/C catalyst 10%. This
> appears to have worked though after a day at atomospheric pressure it
> appears to have only been about 10-20% effective. I work in an
> inorganic lab and dehydrogenation appartus is not readily available
> for increased pressures. I used a baloon.
>
> Can someone suggest possible other routes, an improved method for the
> dehydrogenation, or possibly suggest a better catalyst?
>
> Oh, and if someone can tell me why the deprotection isn't working with
> acids, I am curious as everything I've seen indicaies that it should
> be very facile.
>
> Thanks,
>
> Ken
>

Hi Ken,
you might have success with trimethyl silyl bromide or trimethylsiyl
iodide. I used TMS Br to cleave a variety of peptide protective groups.
See
How to cleave a peptide from a resin without using hydrofluoric acid:
<http://home.earthlink.net/~ejlmp/TMSX1.html>. Good luck.
Eric

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