Date: Fri, 17 Jan 1997 08:21:44 -0700 (MST)
From: John Stewart <John.Stewart@uchsc.edu>
Subject: Re: pepsyn
In-Reply-To: <v02140b03af040fac1f39@[134.197.50.216]>
To: Recipients of ABRF List <abrf@aecom.yu.edu>
Dear David:
We synthesized many LHRH analogs years ago using just pGlu,
without any protecting group. Nothing fancy: use the amount of DMF (use
good pure DMF) necessary to get it in solution in DCM, then couple with
DCC. Works very well.
John M. Stewart, Department of Biochemistry
Univ. of Colorado Medical School, Denver, CO 80262
Phone: 303-315-7534; FAX: 303-315-8215
Email: John.Stewart@UCHSC.edu
On Fri, 17 Jan 1997, David A. Schooley wrote:
> At 10:05 AM 1/15/97, Leo Benoiton quaintly wrote:
> >Dear David Schooley:
> >I am sorry to advise that I submit you really did put your foot in it, as
> >the expression goes.
> >All Boc-, Z and Fmoc-pyroglutamic acid derivatives indeed do exist, and
>
> Yes, Leo, and I managed to do it right when the server burped the message
> SIX times to all members (although James Farmars unrelated message got
> repeated nine times by my count). Thanks to the subsequent responses that
> it is solely for the reason of solubility- I couldn't conceive of a
> possible synthetic reason like preventing aspartimide formation. We are
> just faced with synthesizing our first peptide terminating in pGlu, and
> the pure (S)-isomer is available from Aldrich for $34 per MOLE, a whole lot
> cheaper than ANY of the FMOC amino acids we usually buy!
> NMP as used in the 431A is such a great solvent- surely someone
> ought there must know if pGlu, devoid of protecting groups, has
> appreciable solubility in NMP? I don't want to buy a rarely used
> t-Boc-pGlu if the cheap stuff will do.
>
>
> David A. Schooley
> Dept. of Biochemistry/330
> Univ. of Nevada
> Reno, NV 89557
> schooley@med.unr.edu
> tel: (702) 784-4136; fax (702) 784-1419
>
>
>