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Topic: NMR of Reaction makes NO sense..  (Read 12199 times)

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Offline Messi

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Re: NMR of Reaction makes NO sense..
« Reply #15 on: October 19, 2012, 07:52:52 AM »
For the spectrum below, I find it weird that I get a couple of signals in the 5-6 region! No idea what those would be... If my thioamide did enolize, my hydrozen adajcent to carbon-sulfide group should only be at ~4.85ppm!

Offline Messi

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Re: NMR of Reaction makes NO sense..
« Reply #16 on: October 22, 2012, 11:42:43 AM »
How do I know this? Well I did work with thioketones years ago, and saw the effects in that they like to exist as the thio enol form. I know you have an amide on the other side, but I think the thio ketone is maybe more relevant in the structure. Just my opinion, I may be wrong.
Perhaps someone else will comment on this.

I find it interesting that they are likely to exist in the thio enol form. I mentioned this to my supervisor and he disagreed with me! He said that my thio amide should rarely exist in a thio enol form.

Is this true? Why do thioketones tend to exist in the thio enol form? What is the reasoning?

Offline discodermolide

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Re: NMR of Reaction makes NO sense..
« Reply #17 on: October 22, 2012, 12:02:19 PM »
I'm not sure. It may be because the d orbitals of S are low enough so the there is some overlap with the pi electrons of the enol C=C resulting in more stability.
Now this may be rubbish, if someone else can explain please do so.
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Offline orgopete

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Re: NMR of Reaction makes NO sense..
« Reply #18 on: October 22, 2012, 01:18:47 PM »
I don't see anything that convinces me that I am looking at a pure product, let alone anything resembling the purported product. Tell us what was done and what steps were used to isolated and purify the relation mixture.
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Offline Messi

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Re: NMR of Reaction makes NO sense..
« Reply #19 on: October 22, 2012, 02:12:31 PM »
I don't see anything that convinces me that I am looking at a pure product, let alone anything resembling the purported product. Tell us what was done and what steps were used to isolated and purify the relation mixture.

Hey orgo, I am in the midst of taking a C13 NMR, I'll let you know how it goes. I think I have the correct product. I'll post the NMR once I get it!

Offline OC pro

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Re: NMR of Reaction makes NO sense..
« Reply #20 on: October 22, 2012, 03:57:04 PM »
Additional mass spec data as I suggested would be more convincing!

Offline Messi

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Re: NMR of Reaction makes NO sense..
« Reply #21 on: October 23, 2012, 07:52:24 PM »
So, I got a 13C NMR of two of my products. The other product is currently being analyzed by the NMR machine.

Interestingly enough, my first spectra below was left overnight... but produced a worst spectra then the second one... My second one was only left in the NMR machine for about 2 hours...

Find my spectras below... looks like my desired product was formed!?
« Last Edit: October 23, 2012, 08:09:43 PM by Messi »

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