1. Tardigrade
  2. Question
  3. Chemistry
  4. In the following reaction sequence, the compound J is an intermediate. I xrightarrow[CH3COONa](CH3CO)2O J xrightarrow[(ii) SOCl2, (iii) textanhyd.AlCl3](i)H2, Pd/C J J ( C 9 H 8 O 2) gives effervescence on treatment with NaHCO 3 anda positive Baeyer's test. The compound I is

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Q. In the following reaction sequence, the compound $J$ is an intermediate.
$I \xrightarrow[CH_3COONa]{(CH_3CO)_2O} J \xrightarrow[(ii) SOCl_2, (iii) \text{anhyd.}AlCl_3]{(i)H_2, Pd/C} J$
$J \left( C _{9} H _{8} O _{2}\right)$ gives effervescence on treatment with $NaHCO _{3}$ anda positive Baeyer's test.
The compound $I$ is

JEE AdvancedJEE Advanced 2012

Solution:

In the given reaction, an aromatic aldehyde is condensed with an acid anhydride (Perkin condensation) in the presence of a base to form $\alpha, \beta-$ unsaturated acid (cinnamic acid). This gives effervescence on reaction with $NaH CO _{3}$ and positive test with Bayer's reagent ($1 \%$ alkaline $KMnO_4)$.
$\underset{I}{Ph - CHO} \xrightarrow{(CH_3CO)_2O CH_3COONa} \underset{J\text{(Cinnamic acid)}}{Ph - CH = -COOH} \xrightarrow{NaHCO_3} $ Effervescence
Cinnamic acid $\xrightarrow[\text{(Bayer's reagent)}]{1\% cold, alk; KMnO_4} $ Positive