The diacid shown is heated at about 150 degC until CO2 evolution stops, and the product is treated with Br2/red P followed by water. Which structure is the final organic product?

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JEE Advanced levelSingle correct optionDifficulty 3 of 3co271

The diacid shown is heated at about 150 $^{\circ}$ C until $CO X_{2}$ evolution stops, and the product is treated with $Br X_{2}$ /red P followed by water. Which structure is the final organic product?

AStructure A
BStructure B
CStructure C
DStructure D

Answer: B

The drawn compound is benzylmalonic acid. A malonic acid loses one CO2 on heating to give 3-phenylpropanoic acid; HVZ then brominates the alpha carbon (C2) of that acid, not the benzylic C3 (radical conditions needed), to give 2-bromo-3-phenylpropanoic acid.

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The diacid shown is heated at about 150 ∘C until COX2​ evolution stops, and the product is treated with BrX2​/red P followed by water. Which structure is the final organic product?

Answer: B

More questions on Acidity order and derivative reactivity among drawn carboxylic acids

The diacid shown is heated at about 150 $^{\circ}$ C until $CO X_{2}$ evolution stops, and the product is treated with $Br X_{2}$ /red P followed by water. Which structure is the final organic product?