Chapter 12C, Problem 70P

Propose a structure consistent with each set of data.

a. Compound J: molecular ion at $72$; IR peak at $1710{\text{cm}}^{-1}$; ${}^1\text{H}\text{NMR}$ data (ppm) at $\text{1}\text{.0}\left(\text{triplet}3\text{H}\right)\text{,}\text{2}\text{.1}\left(\text{singlet,}3\text{H}\right)\text{,}\text{and}2.4\left(\text{quartet,}2\text{H}\right)$

b. Compound K: molecular ion at $88$; IR peak at $3600-3200{\text{cm}}^{-1}$; ${}^1\text{H}\text{NMR}$ data (ppm) at $\text{0}\text{.9}\left(\text{triplet}3\text{H}\right)\text{,}\text{1}\text{.2}\left(\text{singlet,}6\text{H}\right)\text{,}1.5\left(\text{quartet,}2\text{H}\right)$, and $1.6\left(\text{singlet,}1\text{H}\right)$.9 (triplet, 3 H), 1.2 (singlet, 6 H)