[Cl:1][C:2]1[CH:3]=[C:4]([CH:9]2[CH2:13][CH2:12][O:11][C:10]2=[O:14])[CH:5]=[CH:6][C:7]=1[Cl:8].[BrH:15].O=S(Cl)Cl.[C:20]1(C)C=CC=CC=1>C(O)(=O)C>[CH3:20][O:11][C:10](=[O:14])[CH:9]([C:4]1[CH:5]=[CH:6][C:7]([Cl:8])=[C:2]([Cl:1])[CH:3]=1)[CH2:13][CH2:12][Br:15]A mixture of 10.2 g (44 mmol) 3-(3,4-dichloro-phenyl)-dihydro-furan-2-one, 55 mL HBr in acetic acid (33%) in 20 mL acetic acid was stirred at room temperature for 16 h. The mixture was poured onto ice/water and extracted with isopropylethyl acetate. The combined organic phases were washed with NaCl aq., dried with Na2SO4 and evaporated. 26.3 g (221 mmol) SOCl2 and 200 mL toluene was added and heated to 80° C. for 3 h. The mixture was evaporated to dryness and 100 mL methanol was added and stirred at room temperature for 30 min. The mixture was evaporated and subjected to column chromatography on silica eluting with a gradient formed from ethyl acetate and heptane. The combined product fractions were evaporated to yield 12.7 g (88%) of the title compound as light brown oil. MS (m/e): 335.5 (MH−).
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