To a stirred solution of diethyl[(6-bromo-2-formylquinolin-7-yl)(difluoro)methyl]phosphonate (525 mg, 1.244 mmol) [Example 8, Step 4] in ethanol (12 mL) at room temperature were added hydroxylamine hydrochloride (130 mg, 1.865 mmol) and sodium acetate (508 mg, 3.73 mmol). The reaction mixture was stirred at 70° C. for 1 hour. It was then poured into aqueous sodium hydrogen carbonate and extracted with ethyl acetate (100 mL), washed with aqueous sodium hydrogen carbonate (2×), brine, dried with MgSO4, and concentrated in vacuo to give crude diethyl[(6-bromo-2-[(E)-(hydroxyimino)methyl]quinolin-7-yl)(difluoro)methyl]phosphonate.
