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Topic: Help needed with determining NMR structure real quick  (Read 6231 times)

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Offline phoenixrising

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Help needed with determining NMR structure real quick
« on: February 26, 2013, 08:48:33 PM »


Is the answer

Since there's a signal between 3 and 4, an ester/ether/alcohol is present in the compound. and C4H8O2 tells me that there's 4 carbons (particularly a butyl chain), and 2 oxygens

Offline discodermolide

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Re: Help needed with determining NMR structure real quick
« Reply #1 on: February 27, 2013, 01:07:23 AM »
The Methyl group of methyl acetate should be around 2ppm, the CH2O around 4. So that spectrum does not correspond to your suggestion.
Is there another way you can arrange the groups in this molecule to give a compound which has that NMR?
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Offline phoenixrising

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Re: Help needed with determining NMR structure real quick
« Reply #2 on: February 27, 2013, 12:42:32 PM »
The Methyl group of methyl acetate should be around 2ppm, the CH2O around 4. So that spectrum does not correspond to your suggestion.
Is there another way you can arrange the groups in this molecule to give a compound which has that NMR?

Wait what?

So you're essentially saying the numbers on the graph indicate the location of each functional group? o.O
« Last Edit: February 27, 2013, 12:52:35 PM by phoenixrising »

Offline phoenixrising

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Re: Help needed with determining NMR structure real quick
« Reply #3 on: February 27, 2013, 12:54:44 PM »
The Methyl group of methyl acetate should be around 2ppm, the CH2O around 4. So that spectrum does not correspond to your suggestion.
Is there another way you can arrange the groups in this molecule to give a compound which has that NMR?

CCOC(C)=O??

Offline discodermolide

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Re: Help needed with determining NMR structure real quick
« Reply #4 on: February 27, 2013, 01:43:45 PM »
That's still not quite correct. It is the same compound you already suggested.
The 3H singlet at around 3.6ppm indicates a CH3 group attached to what?
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Offline phoenixrising

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Re: Help needed with determining NMR structure real quick
« Reply #5 on: February 27, 2013, 06:34:04 PM »
That's still not quite correct. It is the same compound you already suggested.
The 3H singlet at around 3.6ppm indicates a CH3 group attached to what?

An oxygen

Offline discodermolide

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Re: Help needed with determining NMR structure real quick
« Reply #6 on: February 27, 2013, 06:39:30 PM »
Right, so you have an OMe group
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Offline phoenixrising

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Re: Help needed with determining NMR structure real quick
« Reply #7 on: February 27, 2013, 06:46:39 PM »
Right, so you have an OMe group

So the structure is CCC(=O)OC?

Offline discodermolide

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Re: Help needed with determining NMR structure real quick
« Reply #8 on: February 27, 2013, 06:51:58 PM »
Right, methyl propionate.
Can you appreciate the differences?
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Offline phoenixrising

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Re: Help needed with determining NMR structure real quick
« Reply #9 on: February 27, 2013, 07:01:11 PM »
Right, methyl propionate.
Can you appreciate the differences?

yes indeed! :D thanks!!

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