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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: L_I_Z_L on November 21, 2004, 08:41:44 AM

Title: Reduction of OXIMES using ZINC
Post by: L_I_Z_L on November 21, 2004, 08:41:44 AM

I've got a problem with the mechanism of the reduction of an oxime to an amine using Zn in acetic acid.  I know how you can use LiAlH4, but cant transfer these thought to zinc... give me a hint!!

thanks

Title: Re:Reduction of OXIMES using ZINC
Post by: movies on November 21, 2004, 04:56:31 PM

The general mechanism for all Zn/acetic acid reductions is protonation followed by single electron transfer from Zn.  So in this case, protonation of the oxygen (or possibly the nitrogen) of the oxime is the first step.  The second step is addition of an electron to the carbon of the oxime.  If you repeat this process a couple of times you should be able to get to the amine product.

Title: Re:Reduction of OXIMES using ZINC
Post by: L_I_Z_L on November 21, 2004, 05:10:34 PM

is it possible to give that in a little more detail?
thanks

Title: Re:Reduction of OXIMES using ZINC
Post by: Mitch on November 21, 2004, 06:25:11 PM

I just put the Wolff-Kishner Reduction in the Name Reactions section of the website. Although it uses hydrazine you could mentally put an oxygen in place of one of the nitrogens to generate the oxime.

Title: Re:Reduction of OXIMES using ZINC
Post by: L_I_Z_L on November 21, 2004, 06:51:18 PM

I'm finding it quite hard to imagine some of this, i keep writing things down and working it through but end up confusing myself!  if any more handy hints come up i would be so grateful.  Should it be as complicated as i'm finding it?

Thanks mitch and movies

Title: Re:Reduction of OXIMES using ZINC
Post by: AWK on November 22, 2004, 02:15:26 AM

Reducing agent is hydrogen in statu nascendi.

Title: Re:Reduction of OXIMES using ZINC
Post by: movies on November 22, 2004, 01:41:03 PM

Alright, here's the first part:

(https://www.chemicalforums.com/~movies/ZnHOAc.gif)

Title: Re:Reduction of OXIMES using ZINC
Post by: L_I_Z_L on November 23, 2004, 01:11:16 PM

thank you thank you everyone,  I'm done with that problem... the clouds have gone!!!

Title: Re:Reduction of OXIMES using ZINC
Post by: vladi on December 29, 2005, 11:25:11 AM

Hello, I'm Vladi from Greece and my work is about oximes. I find after literature search an other way for the reduction of oximes to hydroxylamines with diborane B2H6. Please help me and send me some references about your way with Zn and acetic acid. I send you the attachment file with the mechanism of the reaction with diborane.Thank you very much!Best wishes for a happy new year 2006!

Vladi


*** Removed attachment.  Please don't post copywritten material on the forums. ***

Title: Re:Reduction of OXIMES using ZINC
Post by: movies on January 03, 2006, 03:28:29 PM

I can't help with the procedure since I've never actually run the Zn/AcOH reaction myself.  Shouldn't be too hard to come by though, it's a pretty common procedure.