[CH3:1][O:2][C:3]([C:5]1[N:10]=[C:9](Br)[C:8]2[N:12]=[C:13]([C:15]3[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=3)[O:14][C:7]=2[C:6]=1[O:21][C:22](=[O:27])[C:23]([CH3:26])([CH3:25])[CH3:24])=[O:4].[CH3:28][O:29][C:30]1[CH:31]=[C:32](B(O)O)[CH:33]=[CH:34][CH:35]=1.C(=O)([O-])[O-].[K+].[K+]>O1CCOCC1.C(OCC)(=O)C.C1C=CC([P]([Pd]([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)[P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1>[CH3:1][O:2][C:3]([C:5]1[N:10]=[C:9]([C:34]2[CH:33]=[CH:32][CH:31]=[C:30]([O:29][CH3:28])[CH:35]=2)[C:8]2[N:12]=[C:13]([C:15]3[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=3)[O:14][C:7]=2[C:6]=1[O:21][C:22](=[O:27])[C:23]([CH3:26])([CH3:25])[CH3:24])=[O:4].[CH3:1][O:2][C:3]([C:5]1[N:10]=[C:9]([C:34]2[CH:33]=[CH:32][CH:31]=[C:30]([O:29][CH3:28])[CH:35]=2)[C:8]2[N:12]=[C:13]([C:15]3[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=3)[O:14][C:7]=2[C:6]=1[OH:21])=[O:4]Under a nitrogen atmosphere 4-bromo-7-(2,2-dimethyl-propionyloxy)-2-phenyl-oxazolo[4,5-c]pyridine-6-carboxylic acid methyl ester (51 mg, 0.12 mmol), 3-methoxyphenylboronic acid (21.5 mg, 0.14 mmol), potassium carbonate (58.7 mg, 0.43 mmol), and tetrakis(triphenylphosphine)palladium(0) (20.4 mg, 0.018 mmol) were suspended in 3 mL of anhydrous 1,4-dioxane. The reaction mixture was heated at 100° C. for 16 hours, then cooled to room temperature, and diluted with ethyl acetate. The mixture was successively washed with water, saturated sodium bicarbonate, and brine solutions. The organic fraction was dried over anhydrous sodium sulfate and concentrated. The residue was purified by flash chromatography eluting from silica gel with a gradient of 0-50% ethyl acetate in hexanes to give 7.5 mg of 7-(2,2-Dimethyl-propionyloxy)-4-(3-methoxy-phenyl)-2-phenyl-oxazolo[4,5-c]pyridine-6-carboxylic acid methyl ester and 24.7 mg of 7-hydroxy-4-(3-methoxy-phenyl)-2-phenyl-oxazolo[4,5-c]pyridine-6-carboxylic acid methyl ester.
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