Question

Complete the following reaction sequences by writing the structural formulae of the organic compounds 'A', 'B' and 'C'.

\[\ce{2-Bromobutan ->[alc. KOH] A ->[][Br2] B ->[][NANH2] C}\]

Answer 1

\[\begin{array}{cc}
\ce{CH3 - CH - CH2- CH3 ->[alc. KOH][\Delta] \underset{(A)}{\underset{But-2-ene}{\underset{80%}{CH3 - CH = CH - CH3}}} + \underset{But-1-ene}{\underset{20%}{CH3 - CH2 - CH = CH2}} + 2KBr + 2H2O}\\
|\phantom{......................................................................................}\\
\ce{\underset{2-Bromobutane}{Br}}\phantom{.....................................................................................}
\end{array}\]

\[\begin{array}{cc}
\ce{\underset{But-2-ene}{CH3 - CH} = CH - CH3 + Br2 -> CH3 - CH - CH - CH3}\\
\phantom{..................................}|\phantom{......}|\\
\phantom{...................................}\ce{\underset{(B)}{\underset{2,3-Dibromobutane}{\ce{Br}\phantom{....}\ce{Br}}}}
\end{array}\]

\[\begin{array}{cc}
\ce{CH3 - CH - CH - CH3 + 2NaNH2 -> CH3 - CH - CH - CH3 + 2NaBr}\\
\phantom{}|\phantom{......}|\phantom{..................................}|\phantom{......}|\phantom{............}\\
\phantom{}\ce{\underset{2,3-Dibromobutane}{\ce{Br}\phantom{....}\ce{Br}}\phantom{............................} \underset{(C)}{\underset{2,3-Diaminobutane}{\ce{NH2}\phantom{...}\ce{NH2}}}}\phantom{..........}
\end{array}\]