Message-Id: <9701081243.AA20893@ibch.siobc.ras.ru>
From: "Vladimir Titov" <titov@ibch>
Date: Wed, 8 Jan 1997 15:44:23 +0300
Subject: Re: PepSyn
To: Recipients of ABRF List <abrf@aecom.yu.edu>
> Two questions for the peptide chemists in the audience.
>
> 1. We wish to make a short peptide (7 residues) that contains an
> N-terminal (3-thio)propionic acid residue. It will look like an
> N-terminal Cys without its amino group. Using FastMoc chemistry on an ABI
> 430 synthesizer, I propose to add the thiopropionyl "residue" as its
> 4-methyl-benzyl-3-thio propionic acid derivative coupled using a normal
> amino acid coupling cycle. Assuming this coupling should work, will the
> 4-methyl-benzyl protecting group be removed by TFA using typical FMOC
> deprotection cocktails? This group has been used in t-Boc chemistry to
> make peptides containing this group and is apparently readily removed
> using HF. Alternatively, we could potentially use Trityl-thio-propionate,
> the analog of Trityl-Cys that we currently use for our Cys derivatives
> but this would require obtaining Trityl-3-thio-propionic acid.
The MBzl group is stable towards TFA. Consider to use HF cleavage or Trt
or Acm protection
Vladimir Titov
MailTo:titov@ibch.siobc.ras.ru
http://titov.siobc.ras.ru