[F:1][CH:2]([F:8])[C:3]([O:5]CC)=O.C[O-].[Na+].CO.[Cl:14][C:15]1[CH:20]=[CH:19][C:18]([C:21](=[O:23])[CH3:22])=[CH:17][CH:16]=1.Cl>C(OCC)C>[F:8][CH:2]([F:1])[C:3](=[O:5])[CH2:22][C:21]([C:18]1[CH:19]=[CH:20][C:15]([Cl:14])=[CH:16][CH:17]=1)=[O:23]
Ethyl difluoroacetate (24.82 g, 200 mmol) was placed in a 500 mL three-necked round bottom flask, and dissolved in diethyl ether (200 mL). To the stirred solution was added 25 weight % sodium methoxide in methanol (48 mL, 210 mmol) via an addition funnel over a 2 minute period. Next, 4'-chloroacetophenone (25.94 g, 200 mmol) was dissolved in diethyl ether (50 mL), and added to the reaction dropwise over 5 minutes. After stirring overnight (18 hours), 1N HCl (250 mL) and ether (250 mL) were added. The organic layer was collected, washed with brine (250 mL), dried over MgSO4, filtered, and concentrated in vacuo to give 46.3 g of a yellow solid. The solid was recrystallized from methylene chloride and iso-octane to give 31.96 g, 69% of the dione, mp 65°-66.5° C.
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