Hydrocarbons - Result Question 73

60. An alkene $(A) C _{16} H _{16}$ on ozonolysis gives only one product $(B) C _8 H _8 O$. Compound $(B)$ on reaction with $NaOH / I _2$ yields sodium benzoate. Compound $(B)$ reacts with $KOH / NH _2 NH _2$ yielding a hydrocarbon $(C) C _8 H _{10}$. Write the structures of compounds $(B)$ and $(C)$. Based on this information two isomeric structures can be proposed for alkene $(A)$. Write their structures and identify the isomer which on catalytic hydrogenation $\left(H _2 / Pd-C\right)$ gives a racemic mixture.

(2001)

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Solution:

  1. $B+NaOH+I _2 \longrightarrow C _6 H _5-COONa$ (Iodoform reaction)

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$B+N _2 H _4 \xrightarrow{KOH} \underset{C_8H_10} {\text{Hydrocarbon (C) }}$ “Wolff-Kishner Reduction”

$\therefore C$ is $C _6 H _5-CH _2-CH _3$

Hence, $A$ can be one of the following :

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I on catalytic hydrogenation, would give meso compound while II on catalytic hydrogenation, would produce racemic mixtures.