Question

Phenol undergoes reactions, which are normally not shown by alcohols. e.g., when PhOH is treated with Zn, it is converted into benzene. Formylation of phenols with chloroform in alkaline solution is known as Reimer Tiemann reaction.

The compound (X) is

Answer 1

2,3-dihydroxybenzaldehyde

Answer 2

Catechol undergoes Reimer-Tiemann reaction with CHCl₃/NaOH followed by H⁺. This reaction introduces a -CHO group ortho to a phenolic -OH group. Catechol has two adjacent -OH groups. Of the two possible ortho positions (C3 and C6 relative to 1,2-benzenediol), the C6 position is less sterically hindered compared to the C3 position (which is between the two -OH groups). Therefore, formylation preferentially occurs at C6, yielding 6-formyl-1,2-benzenediol. When named as a benzaldehyde derivative, with the -CHO group as C1, the hydroxyl groups are at C2 and C3, making the compound 2,3-dihydroxybenzaldehyde.