$\begin{array}{*{20}{c}}
{R = - CH - Cl}\\
{|\,\,}\\
{\,\,\,\,C{H_3}}
\end{array}\,\,\,\,,\,\,\,\,\,\,\,\,\,\,\begin{array}{*{20}{c}}
{S = - CH - Cl}\\
{|\,\,}\\
{Br}
\end{array}$
$C{H_3} - C{H_2} - C{H_2} - CN$ અને $C{H_3} - \mathop {CH}\limits_{\mathop |\limits_{CN} } \,\, - \,\,C{H_3}$