2,5-Dichlorophenol → 2,5-Dichloro-4-hydroxybenzaldehyde

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Reaction Steps

2,5-Dichlorophenol (CAS 583-78-8) (10 g, 0.060 mol), calcium hydroxide (19.5 g, 0.260 mol), and sodium carbonate (22.76 g, 0.220 mol) were suspended in water (140 mL). Chloroform (14.6 g, 0.120 mol) was added for 30 min, and the mixture was refluxed under vigorous stirring for 2 h. The reaction mixture was cooled on ice bath. Concentrated HCl (80 mL) and chloroform (200 mL) were added. The aqueous layer was discarded. The organic one was dried with anhydrous Na2SO4 (10 g) and evaporated in vacuo. The residue was purified by chromatography (silica gel 63-100 μm, 150 g, CCl4→CCl4:EtOAc (60:40)). Fractions containing the product were combined, evaporated to give the title compound (0.88 g, 4.60 mmol, 8%) as yellow crystals. 1H NMR data (DMSO-d6): 11.95 (s, 1H, COH); 10.09 (s, 1H, OH); 7.83 (s, 1H, Ar—H); 7.09 (s, 1H, Ar—H).

Provenance & Evidence