[OH:1][C:2]1[CH:7]=[CH:6][C:5]([C:8](=[O:10])[CH3:9])=[C:4]([CH3:11])[CH:3]=1.O.[OH-].[Na+].Cl[CH:16]([F:18])[F:17]>O1CCOCC1.CCOCC>[F:17][CH:16]([F:18])[O:1][C:2]1[CH:7]=[CH:6][C:5]([C:8](=[O:10])[CH3:9])=[C:4]([CH3:11])[CH:3]=1
To a stirred suspension of 1-(4-hydroxy-2-methyl-phenyl)-ethanone (15 g, 100 mmol) in dioxane (30 mL) is added water (25 mL) followed by the addition of NaOH (20 g, 500 mmol). Reaction is heated to 65° C. and passed gaseous chlorodifluoromethane (30 g, 150 mmol) using a glass tube dipped below the solution level for 75 minutes. Stirred for 30 min longer and left at RT over the weekend. Water (100 mL) and ether (40 mL) are added after transferring to a reparatory funnel. A semi-gelatinous material settled at the bottom of the aqueous layer after some time. The bottom aqueous layer is drained off and extracted with ether (2×40 mL). The combined ether layers are washed with water (5×25 mL), dried over solid K2SO4, evaporated and distilled (0.04 mm Hg, 61-64° C.) to afford 1-(4-difluoromethoxy-2-methyl-phenyl)-ethanone (A4) (16.2 g, 81%). Rf in tlc 0.60 with ether.
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