Q.58. - Organic Chemistry

Question

Question: You have a sample of a compound of molecular formula ${\mathit{C}}_{\mathbf{11}}{\mathit{H}}_{\mathbf{15}}\mathit{N}{\mathit{O}}_{\mathbf{2}}$ , which has a benzene ring substituted by two groups, ${\left(C{H}_3\right)}_{\mathbf{2}}\mathit{N}\mathbf{-}$ and $\mathbf{-}\mathit{C}{\mathit{O}}_{\mathbf{2}}\mathit{C}{\mathit{H}}_{\mathbf{2}}\mathit{C}{\mathit{H}}_{\mathbf{3}}$  , and exhibits the given ${}^{\mathbf{13}}\mathit{C}$  NMR. What disubstituted benzene isomer corresponds to these ${}^{\mathbf{13}}\mathit{C}$  data?

Step-by-Step Solution

Answer

Answer

Step 1: Number of signals in a C 13 NMR spectrum

The  ${}^{\mathbf{13}}\mathit{C}$ NMR spectrum describes the chemical environment of carbon atoms present in a compound.

The number of lines in a  ${}^{13}C$NMR spectrum gives the number of non-identical carbon atoms (the carbon atoms that have different chemical environments) present in a given compound.

Step 2: Analyzing the given data

Given that the compound consists of a disubstituted benzene ring.

The compound consists of  ${\left(C{H}_3\right)}_{2}N$ and $-C{O}_{2}C{H}_{2}C{H}_3$  groups as substituents.

The position of these groups on the ring can be interpreted using the given  ${}^{13}C$NMR spectrum.

Step 3: Structure of the given compound

The given  ${}^{13}C$NMR spectrum consists of four lines indicating the presence of four different (non-identical) carbon atoms.

This indicates that the compound is a para isomer as the ortho and meta isomers will have more than four lines in the ${}^{13}C$ NMR spectrum.

Structure of the given compound