Chemical Forums

Chemistry Forums for Students => Organic Chemistry Forum => Organic Spectroscopy => Topic started by: mjb5676 on November 28, 2012, 08:30:52 PM

Title: (S)-2-hydroxy-3-phenylpropanoic acid C NMR Help
Post by: mjb5676 on November 28, 2012, 08:30:52 PM

I am currently annotating my ¹³C NMR of (S)-2-hydroxy-3-phenylpropanoic acid. I am confused about whether there are peaks from the solvent I used which was acetone-d6. I figure the multiplet to the right may be from the solvent. I have annotated it some, and trying to continue annotating it. If anyone could help me out a bit that would be awesome. Thanks.

Title: Re: (S)-2-hydroxy-3-phenylpropanoic acid C NMR Help
Post by: mjb5676 on November 28, 2012, 08:54:48 PM

I have the peak at ~41 to be carbon 3. And the peak at ~72 to be carbon 2.

Title: Re: (S)-2-hydroxy-3-phenylpropanoic acid C NMR Help
Post by: Dan on November 29, 2012, 02:45:20 AM

Quote from: mjb5676 on November 28, 2012, 08:54:48 PM

I have the peak at ~41 to be carbon 3. And the peak at ~72 to be carbon 2.

I agree with that.

The peaks around 30 and 200 ppm are from (CD₃)₂CO.

For tables of solvent shifts, click here (http://chem.chem.rochester.edu/~nvd/NMRSolventImpurities.pdf).

Title: Re: (S)-2-hydroxy-3-phenylpropanoic acid C NMR Help
Post by: sjb on November 29, 2012, 05:22:04 AM

Quote from: Dan on November 29, 2012, 02:45:20 AM

Quote from: mjb5676 on November 28, 2012, 08:54:48 PM

I have the peak at ~41 to be carbon 3. And the peak at ~72 to be carbon 2.

I agree with that.

The peaks around 30 and 200 ppm are from (CD₃)₂CO.

For tables of solvent shifts, click here (http://chem.chem.rochester.edu/~nvd/NMRSolventImpurities.pdf).

See also http://dx.doi.org/10.1021/om100106e for a slightly updated version

Title: Re: (S)-2-hydroxy-3-phenylpropanoic acid C NMR Help
Post by: OC pro on November 29, 2012, 09:56:05 AM

What do you want more? You have a very clean spectra. Congrats.

You wouldn´t have to open a new thread just for asking the shifts of Acetone-d6. Since you are working with it you should know it before you put it inside the NMR tube or google by yourself.

Title: Re: (S)-2-hydroxy-3-phenylpropanoic acid C NMR Help
Post by: mjb5676 on November 30, 2012, 06:09:30 PM

Thanks for your help everyone. I finished annotating it 2 days ago and it was correct. I appreciate the input.

Title: Re: (S)-2-hydroxy-3-phenylpropanoic acid C NMR Help
Post by: Babcock_Hall on November 30, 2012, 06:24:18 PM

You might ask yourself why the peak near 30 ppm has the multiplet structure that it does.