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JEE · NEET Previous Year Question

' ' is the product which is obtained from propanenitrile and stannous chloride in the presence of hydrochloric acid followed by hydrolysis. ' ' is the product which is obtained from the but-2-ene by the ozonolysis followed by hydrolysis. From the following, which product is not obtained when one mole of ' ' and one mole of ' ' react with each other in the presence of alkali followed by heating?

Topic: JEE PYQ

Answer: D. Full step-by-step solution below.

  1. A2-Methylpent-2-enal
  2. BPent-2-enal
  3. C2-Methylbut-2-enal
  4. D3-Methylbut-2-enal

Correct answer: D

Solution

(d) Product is obtained by the Stephen reduction of propanenitrile ( ).
(Propanal).
Product is obtained by the reductive ozonolysis of but-2-ene ( ).
(Ethanal).
When propanal () and ethanal () react in the presence of alkali followed by heating, they undergo cross-aldol condensation.
Possible products are:
(a) Self-aldol of propanal: (2- Methylpent-2enal).
(b) Self-aldol of ethanal: (But-2-enal).
(c) Cross-aldol (Ethanal as nucleophile): (Pent-2-enal).
(d) Cross-aldol (Propanal as nucleophile): (2-Methylbut-2-enal).
Comparing with the options, 3-Methylbut-2-enal is not formed in any of these reactions.

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