JEE Main · 2023 · Shift-ImediumBIO-017

L-isomer of tetrose X (C4H8O4) gives positive Schiff's test and has two chiral carbons. On acetylation. X yields…

Biomolecules · Class 12 · JEE Main Previous Year Question

Question

L-isomer of tetrose \ceX(C4H8O4)\ce{X (C4H8O4)} gives positive Schiff’s\text{Schiff's} test and has two chiral carbons. On acetylation. \ceX\ce{X} yields triacetate. \ceX\ce{X} also undergoes following reactions

’A’\ceHNO3’X’\ceNaBH4’B’Chiral compound\text{'A'} \xleftarrow{\ce{HNO3}} \text{'X'} \xrightarrow{\ce{NaBH4}} \substack{\text{'B'} \\ \text{Chiral compound}}

'X' is image

Options
  1. a

    Option a

  2. b

    Option b

  3. c

    Option c

  4. d

    Option d

Correct Answerb

Option b

Detailed Solution

Step 1: Structure of Tetrose X — A tetrose with four carbons and two chiral centers must be either erythrose or threose.

Step 2: Reactivity Analysis — Acetylation giving a triacetate indicates three \ceOH-\ce{OH} groups. Since it yields a chiral compound upon reduction with \ceNaBH4\ce{NaBH4}, it must be threose (erythrose gives an achiral meso-polyol).

Step 3: Determining L-Isomer — L-Threose has the \ceOH-\ce{OH} on the left at the highest chiral carbon (C3), matching structure (b).

Key Point: Stereochemical outcomes of reduction reveal the symmetry or lack thereof in the original molecule.

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L-isomer of tetrose X (C4H8O4) gives positive Schiff's test and has two chiral carbons. On… (JEE Main 2023) | Canvas Classes