Chapter 21, Problem 21.78P

An unknown compound D exhibits a strong absorption in its $\text{IR}$ spectrum at $1692{\text{cm}}^{-1}$. The mass spectrum

of D shows a molecular ion at $m/z=150$ and a base peak at $121$. The ${}^1\text{H}\text{NMR}$ spectrum of D is shown

below. What is the structure of D?