Br[C:2]1[CH:7]=[CH:6][C:5]([C:8]2[O:9][C:10]([CH3:13])=[N:11][N:12]=2)=[CH:4][C:3]=1[CH3:14].B([C:18]1[CH:26]=[CH:25][C:21]([C:22]([OH:24])=[O:23])=[CH:20][CH:19]=1)(O)O.C(=O)([O-])[O-].[Na+].[Na+].Cl>COCCOC.O>[CH3:14][C:3]1[CH:4]=[C:5]([C:8]2[O:9][C:10]([CH3:13])=[N:11][N:12]=2)[CH:6]=[CH:7][C:2]=1[C:18]1[CH:26]=[CH:25][C:21]([C:22]([OH:24])=[O:23])=[CH:20][CH:19]=1A stirred solution of 2-(4-bromo-3-methylphenyl)-5-methyl-1,3,4-oxadiazole (EP 0533268 A1) (0.21 g, 0.0008 mole) in a mixture of DME (10 ml) and water (30 ml) under argon was treated with 4-boronobenzoic acid (0.14 g, 0.0008 mole), sodium carbonate (0.39 g, 0.0037 mole) and tetrakis (triphenylphosphine)palladium (0) (16 mg), then heated under reflux for 4 hours. The mixture was acidified with 1M hydrochloric acid and extracted with ethyl acetate. The extract was dried (Na2SO4) and concentrated in vacuo to leave the title compound as a white solid (0.19 g, 78%).
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