[F:1][C:2]1[CH:10]=[CH:9][CH:8]=[CH:7][C:3]=1[C:4]([OH:6])=O.C(Cl)(=O)C(Cl)=O.Br.Br[CH2:19][CH2:20][NH2:21].C(N(CC)CC)C>CN(C=O)C.O.C1C=CC=CC=1.C(Cl)Cl>[F:1][C:2]1[CH:10]=[CH:9][CH:8]=[CH:7][C:3]=1[C:4]1[O:6][CH2:19][CH2:20][N:21]=1A mixture of 2-fluorobenzoic acid (4.5 g, 32.14 mmol), oxalyl chloride (4.1 mL, 48.2 mL), DMF (2 drops) and methylene chloride (40 mL) was heated 2 hours at reflux. The reaction mixture was allowed to cool to 25° C., then stirred approximately 12 hours and concentrated. The residue was slowly added to a suspension of 2-bromoethylamine hydrobromide (5.7 g, 28 mmol), triethylamine (21 mL, 160 mmol) and benzene (200 mL). The mixture was heated 12 hours at reflux, allowed to cool to 25° C., stirred an additional 12 hours and diluted with water. The aqueous layer was separated and extracted with methylene chloride (2×50 mL). The combined extracts were dried (MgSO4) and concentrated. The residue was purified on silica gel by column chromatography eluting with hexanes/ethyl acetate (5:1) to give 2-fluoro-1-(4,5-dihydrooxazol-2-yl)benzene (1.96 g, 11.9 mmol).
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