Question

From the proton spectrum given in Figure 19-45, determine the structure of this compound, a commonly used pain killer; its empirical formula is ${\mathrm{C}}_{10}{\mathrm{H}}_{13}{\mathrm{NO}}_2$.

Short answer

The correct structure is :

Step-by-step solution

Step 1. Introduction

The given proton spectrum is

From the above figure, we can infer that there is an aromatic ring between $6.5-8.0$ppm and this can be shown by the presence of two doublets. The two doublets are obtained by splitting the signals of two types of protons which are Para Substituted Aromatic rings having 4 hydrogens each. This is shown as

Step 2. Explanation

Also, we can infer that there is a group due to the presence of a triplet betweenppm and a group due to the presence of a quartet betweenppm. The Ethyl group indicates that a strong electronegative atom likeis attatched to it. The singlet occuring near ppm and ppm is due to the methyl group and hydrogen bond respectively. The several possible structures for the given empirical formula is

As the compound is mentioned to be a pain killer the structure will be option C.