2725-53-3

98-54-4

100-97-0

2725-53-3

Hexamethylenetetramine (4.77 g, 34.0 mmol) and 4-tert-butylphenol (2.55 g, 17.0 mmol) were dissolved in anhydrous trifluoroacetic acid (30 mL) under nitrogen atmosphere. The reaction mixture was heated to 80 °C and refluxed for 24 hours. Upon completion of the reaction, the mixture was slowly poured into 4 M hydrochloric acid solution (100 mL) and stirred for 10 min, followed by extraction with dichloromethane (2 x 100 mL). The organic phases were combined and washed sequentially with 4 M hydrochloric acid solution (2 × 100 mL) and deionized water (100 mL), dried over anhydrous sodium sulfate, and concentrated under reduced pressure to remove the solvent. The crude product was purified by silica gel column chromatography with dichloromethane as eluent to obtain the target product 5-tert-butyl-2-hydroxybenzaldehyde (1.85 g, yield 61.06%) in the form of yellow viscous liquid.