JEE Main 2014 · 9 Apr · Shift 1 · Chemistry Q53

← JEE Main 2014 · 9 Apr · Shift 1

ChemistrySingle correct+4 / -1Question 53 of 90

The major product of the reaction
$\ce{(CH3)2C(NH2)-C(OH)(CH3)2 ->[NaNO2/H2SO4]}$
is :

2,3-Dimethylbutan-2-ol

Skeletal formula: two adjacent carbons each with two methyls; one carries H, the other OH.

3,3-Dimethylbutan-2-one (pinacolone)

Skeletal formula: a tert-butyl group bonded to a C=O carbon that carries a methyl.

2,3-Dimethylbut-2-ene

Skeletal formula: tetramethylethylene, C=C with two methyls on each carbon.

2,2,3,3-Tetramethylaziridine

Skeletal formula: a three-membered ring of two carbons and NH, each carbon with two methyls.

Answer and worked solution

Official answer: B

Nitrous acid diazotises the $\ce{NH2}$ . Loss of $\ce{N2}$ leaves a tertiary carbocation next to the C-OH carbon. A methyl shifts (semipinacol rearrangement), and the oxocarbenium ion loses $\ce{H+}$ . The product is pinacolone, $\ce{(CH3)3C-CO-CH3}$ .

Topics:Amines Reactive intermediates Named reactions

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JEE Main 2014 · 9 Apr · Shift 1, Chemistry question 53