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Topic: How does this ring open?  (Read 3135 times)

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Offline Raine74

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How does this ring open?
« on: May 04, 2011, 11:52:56 PM »
It's been awhile since I took an organic chemistry class, and while I was going over practice questions, I found 1-Methyl-2-piperidone.



There are 3 functional groups.  The 6 member ring, the tertiary amine, and a carbonyl group (ketone in this case).

I have predict the final structure after it is added to an aqueous solution of sodium hydroxide and then heated.  The alpha hydrogen is the most likely site of deprotonation I think, but the final answer shows a carbon chain.



My question, as the subject would suggest, is how do the electrons move around to force open the ring?  I'm sure this is basic organic chemistry that I'm forgetting, but I thank anyone who is willing to bear through it :)

Offline Dan

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Re: How does this ring open?
« Reply #1 on: May 05, 2011, 03:07:54 AM »
There are 3 functional groups.  The 6 member ring, the tertiary amine, and a carbonyl group (ketone in this case).

A 6-membered ring is not a functional group, and there is no amine or ketone - this is a cyclic amide, which are also called lactams.

For the mechanism of amide hydrolysis, check your textbook/google. It will be analogous to the (BAC2) mechanism of ester hydrolysis - an addition-elimination sequence ubiquitous in carbonyl chemistry.
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Offline Raine74

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Re: How does this ring open?
« Reply #2 on: May 05, 2011, 09:40:02 AM »
Thank you very much!

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