Chapter 17.8, Problem 23CC

Interpretation Introduction

Interpretation: From the given data of IR spectrum, ${}^{\text{1}}\text{H}\text{NMR}$ spectrum and ${}^{\text{13}}\text{C NMR}$ spectrum of the given molecular formula, structure and name of the compound should be given and the product should be predicted when it is treated with chromic acid.

Concept introduction:

• In the IR spectrum, the signal just above 3000 ${\text{cm}}^{\text{-1}}$ confirms the presence of  aromatic ring
• Aromatic compound also produces a series of signals between 1450 and 1650 ${\text{cm}}^{\text{-1}}$ in the IR spectrum
• In IR spectrum,  a $\text{C=O}$ bond will account for the signal at 1686 ${\text{cm}}^{\text{-1}}$
• In the ${}^{\text{1}}\text{H}\text{NMR}$ spectrum, the signals between 6.5 and 8ppm confirms the aromatic ring. The presence of a multiplet near 7 ppm is one of the best way to verify the aromatic ring
• The integration value of the multiplet near 7ppm indicates the extent of substitution. An integration  of 5 indicates monosubstituted ring, an integration of 4 indicates disubsituted ring
• The carbon atoms of aromatic rings typically produce signals in the range of 100-150ppm in ${}^{\text{13}}\text{C NMR}$ spectrum. The number of signals is very helpful in determining the specific substitution for substituted aromatic ring.
• Chromic acid is a strong oxidizing agent