[Br:1][C:2]1[CH:15]=[CH:14][C:5]([O:6][C:7]2[CH:12]=[CH:11][C:10]([OH:13])=[CH:9][CH:8]=2)=[C:4]([F:16])[CH:3]=1.Br[CH:18]([CH3:23])[C:19]([O:21][CH3:22])=[O:20].C(=O)([O-])[O-].[K+].[K+].O>CS(C)=O>[CH3:22][O:21][C:19](=[O:20])[CH:18]([O:13][C:10]1[CH:9]=[CH:8][C:7]([O:6][C:5]2[CH:14]=[CH:15][C:2]([Br:1])=[CH:3][C:4]=2[F:16])=[CH:12][CH:11]=1)[CH3:23]A mixture of the 4-(4-bromo-2-fluorophenoxy)phenol (5.66 g, 0.02 mol) from Step V, methyl 2-bromoproprionate (3.34 g, 0.02 mol) and potassium carbonate (3.06 g, 0.22 mol) in DMSO (30 ml) was stirred, under an atmosphere of nitrogen, at room temperature for 18 hours. The mixture was poured into water (300 ml), and the resulting mixture extracted with ether (2×100 ml). The ether extracts were combined, washed with water (100 ml), dried (MgSO4), and the solvent evaporated to give the desired 2-[4-(4-bromo-2-fluorophenoxy)phenoxy]propionic acid; methyl ester as a yellow oil (6.0 g, 81%); RI=1.5628; NMR (CDCl3) was consistent with the assigned structure. The carbon and hydrogen content was as follows:
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