Chapter 20, Problem 55P

When acetone is treated with anhydrous ammonia in the presence of anhydrous calcium chloride (a common drying agent), crystalline product C is obtained on concentration of the organic liquid phase of the reaction mixture.

These are spectral data for product C:

MS $\left(\text{m/z}\right):155\left(M{.}^{+}\right),140$

IR $\left(c{m}^{-1}\right)$: $3350\left(sharp\right),2850-2960,1705$

${}^{1}H$ NMR $\left(\delta \right)$: $2.3\left(s,4H\right),1.7\left(1H;disappearsin{D}_{2}O\right),and1.2\left(s,12H\right)$

(a) What is the structure of C?

(b) Propose a mechanism for the formation of C.