From: Jonas Nilsson (jonni$##$ifm.liu.se)
Date: Tue Feb 22 2000 - 11:21:22 EST
Hello again.
This is the proposals I got with som comments of mine.
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From: robert eckl <robert.eckl$##$morphochem.de>
Are you really sure that your amidines do not contain chlorine or other
halogens (HCl-
or TFA-salt) ?
Comment: Pretty sure. The samples were hydrogenated too lose a Z-protection
group on the amidine and then run on reversed phase HPLC (C18-column)
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From: "Roux, Stephane" <RouxS$##$corning.com>
Hi,
What was the HPLC column used for separation?
Normal or Reversed phase? and in case of the latter, (CH3)3-Si- treated
after
grafting?
I'm thinking that silica may have been dissolved.
Comment: I'm using reversed phase (C18) column. I don't thing it is
"endcapped". However i've run through 1000ml of solvant wothout any
measurable amound of residue. The only way it could be silica is if the
amidine somehow catalyzed the silica dissolution?!? Anyone ever heard
anything similar?
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From: Bob Gawley <rgawley$##$miami.edu>
What about inorganics?
Comment: Se the above. Inorganics shouldn't go through column.
------------------------------------------
From: "Manuel Toennis" <Manuel.Toennis$##$ch.tum.de>
Could it be, that your amidines act as ligands for some metal
involved in the synthesis? (b, al form NaBH4/LAH)......
There must be something inorganic, a organic stuff remaining intact
at 900 °C can bring you the nobel prize :-)
Comment: I've thought about that. I do catalytic hydrogenation in palladium
on carbon. Maybee the palladium can act as a ligand on the amidine. Can I
please get a second opinion on this. The Palladium is hovever just in
catalytic and not in equimolar amount. The NMR should then show two sets of
peaks (one with and one without palladium ligand).
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