Question

$\xrightarrow[Δ]{H_2SO_4}$ X ; X is :

• A. 2,3-dimethylphenol
• B. 2,6-dimethylphenol
• C. A cyclohexenone, not aromatic.
• D. 2,5-dimethylphenol

Answer 1

Answer: (A)

2,3-dimethylphenol

Answer 2

The reaction involves the acid-catalyzed dehydration of a tertiary alcohol in a cyclic dienone system. The starting material is likely 4-hydroxy-4,5-dimethylcyclohexa-2,5-dien-1-one. The conditions (H₂SO₄, Δ) promote the elimination of water, forming a carbocation at C4. This carbocation then undergoes rearrangement and elimination of a proton to form an aromatic ring. The methyl groups at positions 2 and 3 of the dienone and the hydroxyl group at position 4 lead to the formation of 2,3-dimethylphenol after aromatization.