Re: coupling of 1st aa

Igor Rodionov (rodionov@fibkh.serpukhov.su)
Thu, 15 Oct 1998 19:46:24 +0300

Dear Luca,
You will surely find all relevant procedures in Stewart & Young or
Sheppard-Atherton's Practical Approach.
But I would like to warn you about serious possibility of Fmoc-pGluOAll
formation during strong activation of Glu side chain COOH (in the presence
of DMAP - in particular).
So check resin substitution (by UV-quantitation of Fmoc-Piperidine) on
aliquote before capping!

In your particular case I would prefer to perform side chain anchoring via
nucleophilic substitution using trityl chloride resin and DIEA salt of your
FmocGluOAll (only 10% excess over resin is needed). This type of anchoring
will also minimize loss of the pGluOAll in the course of second amino acid
coupling.
If you would like to try the latter approach you could purchase high
quality trityl chlotide resin at reasonable price from

PepChem Goldammer&Clausen,
Im Winkelrain 73, D-72076 Tuebingen
Tel +49 7071 600384 Fax +49 7071 600393
mobil +49 171 8477888
E-Mail: nils.clausen@uni-tuebingen.de

They will provide the reliable anchoring procedure as well.
(I am not working for PepChem !)

Best wishes,
Igor Rodionov
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Original message:
Hi there!
I'm about to set up a SPPS with Wang Resin. The first aa to link is Fmoc
GluOAll. Can anybody suggest me a procedure to perform this reaction
and a capping protocol to"turn off" the resin functional groups
which won't react with FmocGluOAll?
Thanks a lot
Luca