Question $5[15$ points$]$:

Provide the missing structures $B,C,$ and $D$ and the reagents A and $E.$ No mechanisms required. $(3$ points each$).$

$HN\frac{O_3}{\frac{?}{?}}{H}_{2}S{O}_4$

B

$PC{l}_3$

$C_5{H}_4{N}_2{O}_3$

C

D

${?}_{2.\text{C}\text{u}\text{C}\text{l}}^{1.\text{N}\text{a}\text{N}\frac{O_2}{\frac{?}{?}}HCl}$