$\underset{1}{\mathop{\begin{matrix}
O\,\,\,\,\,\,\,\,\,\,\,\, \\
||\,\,\,\,\,\,\,\,\,\,\,\,\, \\
C{{H}_{3}}COCHC{{H}_{3}} \\
\end{matrix}}}\,$ $\underset{2}{\mathop{\begin{matrix}
\,\,\,\,O \\
\,\,\,\,|| \\
C{{H}_{3}}CCl \\
\end{matrix}}}\,$ $\underset{3}{\mathop{\begin{matrix}
O\,\,\,\,\,\,\,\,\, \\
||\,\,\,\,\,\,\,\,\, \\
C{{H}_{3}}CNHC{{H}_{3}} \\
\end{matrix}}}\,$
$P\;,\;Q\;,\;R$
$C{H_3}COOH + PC{l_5} \to A\mathop {\xrightarrow{{{C_6}{H_6}}}}\limits_{anh.\,AlC{l_3}} $ $B\mathop {\xrightarrow{{{C_2}{H_5}MgBr}}}\limits_{ether} C$