JEE Main · 2021 · 18 Mar 2021 · Shift 2 · Aldehydes Ketones and Carboxylic Acids

In the reaction of hypobromite with amide, the carbonyl carbon is lost as:

(A) $CO_{3}^{2 -}$ ✓ Correct
(B) $HCO_{3}^{-}$
(C)CO
(D) $CO_{2}$

Answer: (A)

Solution

Hypobromite converts the primary amide to an N-bromoamide, which loses its remaining N-H proton to the alkali; the resulting anion rearranges, the alkyl group migrating from carbon to nitrogen as bromide leaves, and an isocyanate is formed. The isocyanate is hydrolysed in the alkaline medium to the amine and carbon dioxide, and the excess alkali takes up that carbon dioxide at once:

RCON H_{2} + B r_{2} + 4 NaOH ⟶ RN H_{2} + N a_{2} C O_{3} + 2 NaBr + 2 H_{2} O

The carbonyl carbon leaves as the carbonate ion,

C O_{3}^{2 -}

JEE Main · 2021 · 18 Mar 2021 · Shift 2 · Single correct option

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