[Br:1][C:2]1[CH:3]=[C:4]([CH:8]=[CH:9][CH:10]=1)[C:5](Cl)=[O:6].Br[C:12]1[CH:18]=[CH:17][CH:16]=[CH:15][C:13]=1[NH2:14].C([O-])([O-])=O.[Cs+].[Cs+].N1C2C(=CC=C3C=2N=CC=C3)C=CC=1>[Cu]I.O1CCOCC1>[Br:1][C:2]1[CH:3]=[C:4]([C:5]2[O:6][C:12]3[CH:18]=[CH:17][CH:16]=[CH:15][C:13]=3[N:14]=2)[CH:8]=[CH:9][CH:10]=1A mixture of 3-bromobenzoyl chloride (6.005 g, 27.36 mmol), 2-bromoaniline (4.707 g, 27.36 mmol), Cs2CO3 (17.83 g, 54.73 mmol), CuI (0.261 g, 1.37 mmol), 1,10-phenanthroline (0.493 g, 2.74 mmol) and anhydrous 1,4-dioxane (50 mL) was degassed with argon at 40° C. for 30 min while stirring. The reaction mixture was then maintained under argon at 120° C. while stirring until TLC (SiO2, 4:1 hexanes-ethyl acetate) confirmed consumption of the starting material (24 h). Upon cooling to RT, the mixture was filtered and the filtrant washed copiously with ethyl acetate (ca. 350 mL). The filtrate was then washed with sat. NaHCO3, H2O and brine, dried over MgSO4, filter and concentrated in vacuo. Purification of the crude product via flash chromatography (SiO2, 4:1-hexanes:ethyl acetate) afforded 2-(3-bromophenyl)benzo[d]oxazole (7.50 g, 100%) as an off-white solid.
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