Water → 5-Fluoro-2-hydroxy-3-methylbenzaldehyde

Participants

Reaction Conditions

Reaction Steps

84 g of 4-fluoro-2-methylphenol are dissolved in 512 ml of trifluoroacetic acid and admixed with 181 g of hexamethylenetetramine in portions. On completion of addition, the reaction solution is heated to 100° C. for 5 hours. After cooling, first 80 ml of 50% sulphuric acid and then 480 ml of water are added dropwise, then the solution is stirred further at room temperature for 3 hours. The reaction solution is extracted three times with dichloromethane. The combined extracts are washed once with water and dried, and the solvent is distilled off under reduced pressure. The residue is extracted repeatedly with n-hexane, the extracts are combined and the solvent is distilled off under reduced pressure. The crude product is subsequently fractionally distilled. 25 g (25% of theory) of a bright yellow solid are obtained having a melting point of 49-52° C. and a boiling point of 70-72° C. at 7 mbar.

Provenance & Evidence