From: Thomas Høeg-Jensen (TSHJ$##$NOVO.dk)
Date: Mon Jul 05 1999 - 07:03:46 EDT
Note, Cbz-NH-OH is an ambident nucleohile, the urethane protective effect an
the nitrogen is only partial.
Could it be that your intermediate is really Cbz-N(Ac)-OH? This could be a
poor Michael nucleophile.
----------------------------
Thomas Hoeg-Jensen, Ph.D
Novo Nordisk A/S, Denmark
-----Original Message-----
From: owner-orglist$##$dq.fct.unl.pt [mailto:owner-orglist$##$dq.fct.unl.pt]On
Behalf Of David Gauthier
Sent: 30. juni 1999 19:03
To: Multiple recipients of list orglist
Subject: ORGLIST: Hydroxylamine
Hi everybody,
I have some problem to do AcO-NH-Cbz from NH2OH HCl and then
HO-NH-Cbz. The H NMR spectrum is very simple for all of these compounds
(maybe too simple !!!). I think that I don't have the right product
because the Michael addition is problematic when I use MY AcO-NH-Cbz
produced. That Michael addition is supposed to be quantitative !
I made HO-NH-Cbz by mixing H2NOH HCl with Bn-O-CO-Cl in CH2Cl2 (with a
solution of NaHCO3 aq). Then, I made AcO-NH-Cbz by mixing the
HO-NH-Cbz produced with Acetyl chloride in THF, and added dropwise a
solution of NaOH 1N. The product seems clean on H NMR, but the next
step (Michael add.) doesn't work.
If you some ideas, or if you've seen papers about my problem, tell me.
Thank you very much
David Gauthier
MSc University of Sherbrooke
Canada
gauthier.david$##$videotron.ca
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