ORGLIST: Reductive amination with NaCNBH3 at low pH

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From: will jones (willjones46$##$
Date: Tue Dec 14 2004 - 11:27:29 EST

Hi there

I am wanting to reductively aminate a fluorophore into the reducing end of
an oligosaccharide for subsequent reactions.

I have dug up loads of stuff on this and they have all said pretty much the
same thing

Dissolve fluorophore in 0.15M AcOH/H2O (3:17 v/v), add to oligosaccharide.
Add NaCNBH3 (1.0M in DMSO)
Incubate for 16 hours at 37 degC
I was planning on testing for the lack of reducing end of the
oligosaccharide by whether Cu(II) is reduced to Cu(I), which I have used
before for presence of reducing end of oligosaccharides.

My question is to anyone who has worked with NaCNBH3.

Can you work below pH7 with it or will it give off HCN? The reason I ask is
I know that NaBH4 gives off H2 below pH7 when Ive used it for other
reduction reactions.

Ideal conditions quoted appear to be pH2.3 ish. Can someone promise me no
HCN is going to be given off!!???



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