From: Guido de Silvestri (guidods$##$etb.net.co)
Date: Tue May 16 2006 - 16:46:00 EDT
Dear Mr. Gao...
It may be waited that the Indole could have the secondary amines and the
aromatic substances properties, but it does not have the typical amine
properties.
The p electrons from the nitrogen incorporated to the pi orbital, leave
nitrogen without no shared electrons, causing to the substance, the
presence of a very weak basic property, even though the indole can be
rated as a secondary amine. I think that the hydrogen atom from the
nitrogen should be than acid enough, which can be subtract with
potassium hydroxide.
So... maybe that is what happening... Try first with KOH, heating the
system to reflux.
Best regards,
Guido de Silvestri
-----Mensaje original-----
De: everybody-bounces$##$orglist.net [mailto:everybody-bounces$##$orglist.net]
En nombre de Peng Gao
Enviado el: Viernes, 12 de Mayo de 2006 05:49 a.m.
Para: everybody$##$orglist.net
Asunto: ORGLIST: Deprotection of the indole N
Dear Colleagues£¬
Recently I was confused by the deprotection of the indole N. The
protection
group of the indole N is Bn, because of the ¦Á¦Âunsaturated carbonyl and
another
ester group in my molecular, it can¡¯t be deprotected by Na / NH3(l) and
Pd / H2.
I tried other methods from crossfire and scifinder (all kinds of lewis
acid,;t-BuOK, DMSO; protonic acid; LDA), they all didn¡¯t work or made
the
substrate decompose. At this time, my boss suggest me change the Bn to
PMB, but
when I make it to PMB, I tried all the lewis acid, protonic acid , DDQ,
CAN.
Unfortunately, the reaction is also just like the Bn compound. Did
someone know
the other methods of deprotection of the Bn or PMB group at the indole
N.
Any suggestion will be welcome. Thank you for your attention and help!
-Peng
Peng Gao
Prof. Xu Group
National Laboratory of Applied Organic Chemistry
(http://sklaoc.lzu.edu.cn/)
Department of Chemistry, Lanzhou University
Lanzhou P.R. China
Email: pgao00$##$st.lzu.edu.cn
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