$C{H_3}CN\xrightarrow{{Na + {C_2}{H_5}OH}}X\xrightarrow{{HN{O_2}}}Y\mathop {\xrightarrow{{{K_2}C{r_2}{O_7}}}}\limits_{{H_2}S{O_4}} Z$
(Figure) $\xrightarrow[FeB{{r}_{3}}]{B{{r}_{2}}}B\xrightarrow{Sn\,/\,HCl}C$ $\xrightarrow[HCl]{NaN{{O}_{2}}}D\xrightarrow[HBr]{CuBr}E$