1 $\begin{array}{*{20}{c}}
{O\,\,\,\,} \\
{||\,\,\,\,\,} \\
{Ph - C - C{H_3},}
\end{array}$ $Ph-CH_2-CHO$
2 $\begin{array}{*{20}{c}}
{O\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,} \\
{||\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,} \\
{Ph - C - NH - C{H_3},}
\end{array}$ $\begin{array}{*{20}{c}}
{\,\,\,\,\,\,\,\,\,O\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,} \\
{\,\,\,\,\,\,\,||\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,} \\
{C{H_3} - C - NH - Ph}
\end{array}$
3 $\begin{array}{*{20}{c}}
{O\,\,\,\,} \\
{||\,\,\,\,\,} \\
{Ph - C - C{H_3},}
\end{array}$ $\begin{array}{*{20}{c}}
{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\begin{array}{*{20}{c}}
{\,\,\,\,\,\,\,\,\,\,\,\,OH} \\
\,\,\,\,\,\,\,\,\,|
\end{array}} \\
{Ph - C = N} \\
| \\
{\,\,\,\,\,\,\,C{H_3}}
\end{array}$
4