[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.C(Cl)Cl.C1C=CC=CC=1>[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]=1
A mixture of 2-fluorobenzoic acid (4.5 g, 32.14 mmol) and oxalyl chloride (4.1 mL, 48.2 mL) in 2 drops of DMF and 40 mL of methylene chloride was heated at reflux for 2 hours. The mixture was allowed to cool to room temperature and stirred for approximately 12 hours and then the solvents were removed by rotary evaporation. The residue was slowly added to a suspension of 2-bromoethylamine hydrobromide (5.7 g, 28 mmol) and triethylamine (21 mL, 160 mmol) in 200 mL of benzene. The mixture was heated at reflux for 12 hours, allowed to cool to room temperature and then stirred for an additional 12 hours. The mixture was quenched with water and 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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