An organic compound $\mathrm{A}$ upon reacting with ${\mathrm{NH}}_3$ gives $\mathrm{B}$. On heating, $\mathrm{B}$ gives $\mathrm{C}$. $\mathrm{C}$ in presence of $\mathrm{KOH}$ reacts with ${\mathrm{Br}}_2$ to give ${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{NH}}_2$. $\mathrm{A}$ is