Dichlorophen → [4-Chloro-2-(5-chloro-2-hydroxy-benzyl)-phenoxy]-acetic acid benzyl ester

2,2′-Methylene-bis(4-chloro-phenol) (12 g, 44.6 mmol) is dissolved in DMF (100 mL). Lithium carbonate (3.3 g, 44.6 mmol) is added, followed by benzyl-2-bromoacetate (7.7 mL, 49 mmol). The suspension is stirred at 80° C. for 8 hours. Further benzyl-2-bromoacetate (1 mL, 6.4 mmol) is added and stirring continued at 100° C. for 4 hours. The reaction mixture is evaporated to dryness, water is added to the residue which is acidified to pH 1 with 2 M aqueous HCl and extracted with EtOAc. The organic layer is washed with brine, dried (MgSO4) and evaporated. The crude product is purified by flash column chromatography over silica gel eluting with 4:1 iso-hexane:EtOAc. The product is suspended in iso-hexane, dissolved in the minimum volume of EtOAc, seeded and left to stand. The resultant solid is collected by filtration, washed with iso-hexane and dried to give [4-chloro-2-(5-chloro-2-hydroxy-benzyl)-phenoxy]-acetic acid benzyl ester; m.p.=135-137° C.