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JEE MAIN 2026 · Organic Compounds Containing Nitrogen

JEE Main 2026 Session 2 Question Paper: 8 Apr, Shift 2 (B.E./B.Tech), question 67

Updated
Single correct+4 / -1Answer matches NTA’s final key

Consider the following reaction.

A piperidin-2-one ring whose nitrogen carries a CH(CH3)–CHO group, treated with (i) NaBH4/MeOH, (ii) NaOH(aq.), heat, (iii) H3O+, to give P

The major product (P) formed is:

Choose one

Solution

Solution

Take the three steps in order.

  1. NaBH4_4/MeOH reduces aldehydes and ketones but not amides. The side-chain –CHO becomes –CH2_2OH; the lactam C=O is untouched.
  2. NaOH(aq), heat hydrolyses the lactam (a cyclic amide). The C(=O)–N bond breaks and the ring opens to a carboxylate and a secondary amine: −^-OOC–(CH2_2)4_4–NH–CH(CH3_3)–CH2_2OH.
  3. H3_3O+^+ protonates the carboxylate.

P is HOOC–(CH2_2)4_4–NH–CH(CH3_3)–CH2_2OH, an open-chain amino acid that kept its carboxylic acid group (option C). Option D would need the acid reduced too, which NaBH4_4 cannot do.

Answer: (C).

Answer checked against the official answer key. The solution is our own working.

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