Following are \({ }^{1} \mathrm{H}\)-NMR and \({ }^{13} \mathrm{C} N \mathrm{NMR}\) spectral data for compound \(\mathrm{G}\left(\mathrm{C}_{10} \mathrm{H}_{10} \mathrm{O}\right)\). From this information, deduce the structure of compound \(G\). $$ \begin{array}{lrr} { }^{1} \text { H-NMR } & \multicolumn{2}{c}{{ }^{13} \text { C-NMR }} \\ \hline 2.50(\mathrm{t}, 2 \mathrm{H}) & 210.19 & 126.82 \\ 3.05(\mathrm{t}, 2 \mathrm{H}) & 136.64 & 126.75 \\ 3.58(\mathrm{~s}, 2 \mathrm{H}) & 133.25 & 45.02 \\ 7.1-7.3(\mathrm{~m}, 4 \mathrm{H}) & 128.14 & 38.11 \\ 127.75 & & 28.34 \\ \hline \end{array} $$

Short Answer

Expert verified
Answer: The structure of compound G is para-methoxyethylbenzoate.

Step by step solution

01

Analyzing the given \({ }^{1}\mathrm{H}\)-NMR spectrum

From the given \({ }^{1}\mathrm{H}\)-NMR spectrum, we have four sets of signals: 1. A triplet at 2.50 ppm integrating to 2 H 2. A triplet at 3.05 ppm integrating to 2 H 3. A singlet at 3.58 ppm integrating to 2 H 4. A multiplet between 7.1 and 7.3 ppm integrating to 4 H
02

Analyzing the given \({ }^{13}\mathrm{C}\)-NMR spectrum

From the given \({ }^{13}\mathrm{C}\)-NMR spectrum, we have eight different signals: 1. 210.19 ppm 2. 136.64 ppm 3. 133.25 ppm 4. 128.14 ppm 5. 127.75 ppm 6. 126.82 ppm 7. 126.75 ppm 8. 45.02 ppm 9. 38.11 ppm 10. 28.34 ppm
03

Assigning hydrogen environments

Now, let's assign the environments for the hydrogens using the \({ }^{1}\mathrm{H}\)-NMR spectrum: 1. A triplet at 2.50 ppm integrating to 2 H: This is characteristic for a methylene (-CH2-) group next to an unsaturated system (alkenes, carbonyls). 2. A triplet at 3.05 ppm integrating to 2 H: This is also characteristic for a methylene (-CH2-) group but next to an electronegative atom (oxygen or nitrogen). 3. A singlet at 3.58 ppm integrating to 2 H: A singlet indicates no coupling, indicating these hydrogens are not near another hydrogen. This suggests these hydrogens are attached to an oxygen in a methoxy group (-O-CH3). 4. A multiplet between 7.1 and 7.3 ppm integrating to 4 H: This corresponds to a group of four hydrogens in an aromatic environment.
04

Assigning carbon environments

Using the \({ }^{13}\mathrm{C}\)-NMR spectrum, we can assign the environments for the carbons: 1. 210.19 ppm: Carbonyl carbon (C=O) 2. 136.64 ppm, 133.25 ppm, 128.14 ppm, 127.75 ppm, 126.82 ppm, and 126.75 ppm: These signals are characteristic of aromatic carbons. 3. 45.02 ppm: Methoxy carbon attached to an oxygen (-O-CH3) 4. 38.11 ppm: Methylene (-CH2-) carbon next to a carbonyl group or double bond 5. 28.34 ppm: Methylene (-CH2-) carbon next to an electronegative atom (oxygen or nitrogen)
05

Deduce the structure of compound G

Combining the information obtained from the \({ }^{1}\mathrm{H}\)-NMR and \({ }^{13}\mathrm{C} \mathrm{NMR}\) spectra, we can propose a structure for compound G: 1. The presence of four aromatic hydrogens with six aromatic carbons suggests a disubstituted benzene ring. 2. The presence of a carbonyl group and a methoxy group suggests an ester functional group attached to the benzene ring. 3. Two different methylenes with triplets suggest two ethyl groups with different chemical environments. One ethyl group is attached to the benzene ring, and the other is linked to the carbonyl carbon of the ester. Therefore, the structure of compound G is ethyl benzoate with a methoxy group para to the ester, or para-methoxyethylbenzoate with the molecular formula \(\mathrm{C}_{10}\mathrm{H}_{10}\mathrm{O}\).

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