[Br:1][C:2]1[CH:3]=[CH:4][C:5]([CH:12]=O)=[C:6]2[C:10]=1[O:9][C:8]([CH3:11])=[N:7]2.Cl.[NH2:15][OH:16].C(N(CC)CC)C>CO.O.C(OCC)(=O)C>[Br:1][C:2]1[CH:3]=[CH:4][C:5](/[CH:12]=[N:15]/[OH:16])=[C:6]2[C:10]=1[O:9][C:8]([CH3:11])=[N:7]2
To a suspension of 7-bromo-2-methyl-benzo[d]oxazole-4-carbaldehyde (3.23 g) in a mixture of methanol and water (7:3) (60 ml) were added successively hydroxylamine hydrochloride (1.03 g) and triethylamine (2.06 ml) and the reaction mixture was stirred at ambient temperature for 1 hour. The reaction mixture was diluted with ethyl acetate (200 ml) and water (200 ml). The phases were separated and the aqueous phase was extracted with ethyl acetate (150 ml). The combined organic extracts were washed with brine (200 ml), dried over sodium sulfate and concentrated to give (E)-7-bromo-2-methyl-benzo[d]oxazole-4-carbaldehyde oxime (3.61 g) as a brown solid. 1H-NMR (400 MHz, CDCl3): 9.47 (s, 1H) 7.47 (d, 1H), 7.33 (d, 1H), 2.74 (s, 3H) ppm.
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