[Br:1][C:2]1[CH:15]=[CH:14][C:5]2[C:6]3[C:12](=O)[CH2:11][CH2:10][CH2:9][C:7]=3[O:8][C:4]=2[CH:3]=1.C([O-])(=O)C.[Na+].Cl.[NH2:22][OH:23]>O.C(O)C>[Br:1][C:2]1[CH:15]=[CH:14][C:5]2[C:6]3[C:12](=[N:22][OH:23])[CH2:11][CH2:10][CH2:9][C:7]=3[O:8][C:4]=2[CH:3]=1
A mixture of the product of step A (6.80 g, 25.7 mmol), sodium acetate (3.16 g, 38.5 mmol) and hydroxylamine hydrochloride (2.67 g, 38.5 mmol) in water (28 mL) and ethanol (14 mL) was heated to 85° C. for 7 h. After cooling to 5° C., the reaction mixture was filtered. The solid obtained was washed with cold water and dried in vacuo to give 7-bromo-3,4-dihydrodibenzo[b,d]furan-1(2H)-one oxime (1.05 g, 15%) as an off-white solid: 1H NMR (DMSO-d6, 300 MHz) δ 10.95 (s, 1H), 7.88 (d, J=1.8 Hz, 1H), 7.74 (d, J=8.4 Hz, 1H), 7.47 (dd, J=8.4, 1.8 Hz, 1H), 2.87 (t, J=6.3 Hz, 2H), 2.69 (t, J=6.3 Hz, 2H), 2.03-1.89 (m, 2H).
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