A mixture in ethanol (20 mL) of 2-[(2,6-dichloro-3-methylphenyl)amino]benzaldehyde (1.10 g, 3.9 mmol), prepared as in step 1 above, O-carboxymethyl hydroxylamine hemihydrochloride (0.945 g, 4.3 mmol), and pyridine (8 mL) was stirred at reflux for 18 hours. After cooling the reaction was concentrated and the residue was acidified to pH 2 with 10% aqueous citric acid. The mixture was then extracted with ethyl acetate (4×100 mL), the combined organic layers were washed with water and brine, dried over MgSO4, filtered, evaporated in vacuo. Purification by chromatography on silica gel (9:1 hexane/ethyl acetate, followed by 9:1 CH2Cl2 /CH3OH) and crystallization from ethyl acetate-ether-hexane gave 2-[(2,6-dichloro-3-methylphenyl)aminophenyl]benzaldehyde-O-carboxymethyl oxime (751 mg, 54%). mp 129°-130° C.; 1H NMR (300 MHz, DMSO-d6)δ2.37 (s, 3H), 4.70 (s, 2H), 6.21 (d, J=9 Hz, 1H), 6.83 (t, J=7.5 Hz, 1H), 7.17 (t, J=7.5 Hz, 1H), 7.33 (d, J=9 Hz, 1H), 7.45 (d, J=9 Hz, 1H), 7.50 (d, J=9 Hz, 1H), 8.58 (s, 1H), 8.73 (s, 1H), 12.81 (broad s, 1H); MS (DCI-NH3) m/z 353 (M+H)+, 370 (M+NH4)+. Anal. Calcd for C16H14Cl2N2 O3 : C, 54.41, H, 4.00, N, 7.93. Found: C, 54.13, H, 3.92; N, 7.69.
