3,5-DICHLORO-4-HYDROXYBENZALDEHYDE

2432-12-4

2314-36-5

General procedure for the synthesis of 3,5-dichloro-4-hydroxybenzaldehyde from 2,6-dichloro-4-methylphenol: A mixture of the substrate 2,6-dichloro-4-methylphenol (1 mmol), cobalt salts (n1 mol%), and NaOH (n2 equiv.) in ethylene glycol (5 mL) was subjected to a stirring reaction under an atmosphere of oxygen (1 atm) at 80°C for 8 hours. Upon completion of the reaction, hydrochloric acid (10 mL, 2%) and methyl tert-butyl ether (MTBE, 10 mL) were sequentially added to the reaction mixture. The organic layer was separated and the aqueous phase was further extracted with MTBE (10 mL x 2). All organic phases were combined, dried with anhydrous sodium sulfate and concentrated to obtain the residue. The residue was purified by silica gel column chromatography (eluent: petroleum ether/ethyl acetate, 10:1, v/v) to afford the target product 3,5-dichloro-4-hydroxybenzaldehyde.