The structures of major products \(\mathrm{A}, \mathrm{B}\) and C in the following reaction are sequence.

JEE Main · 2023 · 01 Feb 2023 · Shift 2 · Aldehydes Ketones and Carboxylic Acids

The structures of major products

A, B

and C in the following reaction are sequence.

(A)(see structures)
A
B
C
(B)(see structures)
A
B
C
(C)(see structures)
A
B
C
(D)(see structures)
A
B
C
✓ Correct

Answer: (D)

Solution

The aldehyde 2-methylpentanal first adds hydrogen cyanide, delivered through its bisulphite adduct followed by cyanide, to give the cyanohydrin, so product A is the

α

-hydroxynitrile in which the hydroxyl and the nitrile sit on the former carbonyl carbon. Treating this nitrile with lithium aluminium hydride reduces the

- C \equiv N

group completely to a primary amine while the hydroxyl is left untouched, so product B is the amino alcohol bearing

- C H_{2} N H_{2}

. Warming the same cyanohydrin with aqueous hydrochloric acid hydrolyses the nitrile to a carboxyl group, so product C is the

α

-hydroxy carboxylic acid. The correct set of products is the cyanohydrin, then the amino alcohol, then the

α

-hydroxy acid.

JEE Main · 2023 · 01 Feb 2023 · Shift 2 · Single correct option

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JEE Main · 2023 · 01 Feb 2023 · Shift 2 · Aldehydes Ketones and Carboxylic Acids

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