Chapter 14, Problem 15PP

PRACTICE PROBLEM 14.15

Four benzenoid compounds, all with the formula ${\text{C}}_{\text{7}}{\text{H}}_{\text{7}}\text{Br}$, gave the following IR peaks in the 680–860 ${\text{cm}}^{-\text{1}}$ region:

A, 740 ${\text{cm}}^{-\text{1}}$ (strong)

B, 800 ${\text{cm}}^{-\text{1}}$ (very strong)

C, 680 ${\text{cm}}^{-\text{1}}$ (strong) and 760 ${\text{cm}}^{-\text{1}}$ (very strong)

D, 693 ${\text{cm}}^{-\text{1}}$ (very strong) and 765 ${\text{cm}}^{-\text{1}}$ (very strong)

Propose structures for A, B, C, and D.