Paragraph for Question Nos. 39 to 41
Reimer-Tiemann reaction introduces an aldehyde group, on to the aromatic ring of phenol, ortho to the hydroxyl group. This reaction involves electrophilic aromatic substitution. This is a general method for the synthesis of substituted salicylaldehydes as depicted below.
(Scheme: 4-methylphenol (p-cresol) → intermediate I → II → III, where III is 2-hydroxy-5-methylbenzaldehyde; the last step is acidification.)
(The paragraph is not printed in the official archive copy (which reproduces only the questions with their answers); its text is restored from the JEE 2007 question paper.)