$\begin{matrix}
   \begin{matrix}
   \,\,\,\,\,C{{H}_{3}}  \\
   |  \\
\end{matrix}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,  \\
   C{{H}_{3}}-C-C{{H}_{2}}C{{H}_{2}}OH  \\
   |\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,  \\
   C{{H}_{3}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,  \\
\end{matrix}$ $\xrightarrow[{{H_2}O,heat}]{{{K_2}C{r_2}{O_7};{H_2}S{O_4}}}A$ $\xrightarrow{{SOC{l_2}}}B\xrightarrow[{(2{\kern 1pt} mole)}]{{{{(C{H_3})}_2}NH}}C$ $\xrightarrow[{2.{\kern 1pt} {H_2}O}]{{\begin{array}{*{20}{c}}
  {1.{\kern 1pt} LiAl{H_4}} \\ 
  {diethyl{\kern 1pt} {\kern 1pt} ether} 
\end{array}}}D$

$(1)$   $C{H_3}C{H_2}N{H_2}$                    $(2)$   $\begin{array}{*{20}{c}}
{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,C{H_2}C{H_3}}\\
{\,\,\,\,\,\,\,\,\,\,\,\,\,\,|\,\,\,\,}\\
{\,C{H_3}C{H_2}NH\,\,\,\,\,\,\,}
\end{array}$

$(3)$   $\begin{array}{*{20}{c}}
{\,\,\,\,\,\,\,C{H_3}}\\
{\,|}\\
{{H_3}C - N - C{H_3}}
\end{array}$                                $(4)$     $\begin{array}{*{20}{c}}
{\,\,\,\,\,\,\,C{H_3}}\\
{\,|}\\
{Ph - N - H}
\end{array}$