$\left( A \right)\xrightarrow{{\operatorname{Re}duction}}\left( B \right)\xrightarrow{{HN{O_2}}}{C_2}{H_5}OH$

$(A)$ $\begin{matrix}
O\,\,\,\,\,\,\,\,\,\, \\
||\,\,\,\,\,\,\,\,\,\,\,\, \\
R-C-NHBr \\
\end{matrix}$ $(B)$ $R-NH-Br$
$(C)$ $R-N=C=O$ $(D)$ $\begin{matrix}
\,\,\,\,O\,\,\,\,\,\,\,\,\,\, \\
\,\,\,\,\,\,||\,\,\,\,\,\,\,\,\,\,\,\, \\
R-C-NB{{r}_{2}} \\
\end{matrix}$
