Chapter 14, Problem 14.55P

Identify the structures of isomers A and B (molecular formula ${\text{C}}_{\text{9}}{\text{H}}_{\text{10}}\text{O}$).

Compound A: IR peak at $174{\text{2 cm}}^{-1}$; ${}^{\text{1}}\text{H}$ NMR data $\left(\text{ppm}\right)$ at $\text{2}\text{.15}\left(\text{singlet, 3H}\right)\text{, 3}\text{.70}\left(\text{singlet, 2H}\right)\text{, and 7}\text{.20}\left(\text{broad singlet, 5H}\right)$.

Compound B: IR peak at $1688{\text{ cm}}^{-1}$; ${}^{\text{1}}\text{H}$ NMR data $\left(\text{ppm}\right)$ at $1.22\left(\text{triplet, 3H}\right)\text{, 2}\text{.98}\left(\text{quartet, 2H}\right)\text{, and 7}\text{.28-7}\text{.95}\left(\text{multiplet, 5H}\right)$.