Organic Chemistry - 1H and 13C NMR Problem. HELP

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Homework Statement

Determine the structure of the compound given the information below

Homework Equations

Molecular Formula:
C8H6O4

1H NMR:
1.57 (d, J=8.66 Hz, 1 H) 1.77 (d, J=8.66 Hz, 1 H) 3.51 (d, J=3.00 Hz, 1 H) 3.51 (d, J=3.00 Hz, 1 H) 3.60 (sc,J=7.56, 3.00 Hz, 1 H) 3.60 (sc, J=7.56, 3.00 Hz, 1 H) 6.31 (s, 2 H) 13C NMR:
46.10 (s, 1 C) 46.10 (s, 1 C) 47.20 (s, 1 C) 47.20 (s, 1 C) 52.80 (s, 1 C) 135.60 (s, 1 C) 135.60 (s, 1 C) 171.50 (s, 1 C) 171.50 (s, 1 C)

The Attempt at a Solution

So, here's what I've been able to figure out thus far:

I decided to first find the degree of unsaturation in this molecule, which comes out as 6.

From that, my first thought was that I could get 4 degrees from a benzene ring, and 2 degrees from 2 carbonyls (somehow) attached to the ring.

Based on the highest signal of the carbon NMR, I know that one of the carbons is going to be some sort of R(CO)X derivative, and thus I won't have any hydroxyls within my final structure.

Given the highest signal on my proton NMR, I figured that there were only going to be 2 symmetrical hydrogen atoms (somewhere) on my ring. Either that, or the remote possibility of putting a CH2 right between two esters. There's also the possibility of having a double end, with one end being attached directly to two esters.

My biggest problem comes from the fact that I have two proton signals in the 1.57-1.77 range, and the 3.51-3.60 range. This tells me that I have some carbons NOT involved in the ring, but at the same time I have carbons that are adjacent to either side of the ester groups.

I've tried designing a few structures, but they always keep falling short of either the molecular formula, the integration of each shift, or the group I tried adding doesn't match with the observed deshielding. What are your thoughts, guys? All feedback is greatly appreciated!

 

[nate808]

Based on the information provided, it appears that the compound has a molecular formula of C8H6O4, which suggests that it contains a benzene ring and two carbonyl groups. The 1H NMR spectrum shows signals at 1.57 and 1.77 ppm, which are characteristic of two symmetrical hydrogen atoms on a benzene ring. The presence of two signals at 3.51 and 3.60 ppm suggests the presence of two methylene groups, possibly attached to the carbonyl groups. The 13C NMR spectrum also supports this, with signals at 46.10 and 47.20 ppm that are characteristic of carbons attached to a methylene group, and signals at 135.60 and 171.50 ppm that are characteristic of carbons in a benzene ring and a carbonyl group, respectively.

Based on this information, it is likely that the compound is a derivative of benzoic acid, with two ester groups attached to the ring. This would explain the presence of the two methylene groups and the carbonyl groups. The structure could potentially be something like 4,4'-methylenebis(benzoic acid) dimethyl ester, which would have the correct molecular formula and explain the observed NMR signals. However, without additional information or confirmation from further experiments, it is difficult to say for sure. It would be helpful to perform additional experiments, such as IR spectroscopy or mass spectrometry, to confirm the proposed structure.