[CH3:1][O:2][C:3]([C:5]1[O:9][C:8]([C:10]2[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=2)=[N:7][C:6]=1[CH3:16])=[O:4].[Br:17]N1C(=O)CCC1=O.C(OOC(=O)C1C=CC=CC=1)(=O)C1C=CC=CC=1>C1C=CC=CC=1.C(OCC)(=O)C>[CH3:1][O:2][C:3]([C:5]1[O:9][C:8]([C:10]2[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=2)=[N:7][C:6]=1[CH2:16][Br:17])=[O:4]4-Methyl-2-phenyl-oxazole-5-carboxylic acid methyl ester (3.2 g, 14.7 mmol, prepared according to Cynkowski, T.; Cynkowska, G.; Ashton, P.; and Crooks, P. A. J. Chem. Soc., Chem. Commun. 1995, 2335), N-bromosuccinimide (2.69 g, 15.1 mmol), and benzoyl peroxide (356 mg, 1.47 mmol) were suspended in 37 mL of benzene and the mixture heated at reflux temperature for 16 hours. The reaction mixture was cooled and diluted with ethyl acetate. The mixture was washed successively with saturated bicarbonate solution, brine, saturated ammonium chloride solution, and brine. The organic solvent was dried, filtered, and concentrated. The crude product was purified by flash chromatography eluting from silica gel with a gradient of 0-40% ethyl acetate in hexanes to give 1.88 g of the title compound as a yellow solid. MS: (+) m/z 296.0, 298.0 (M+1, 79Br/81Br).
Loading…
