Pyridine → HCID 178498358, compound

Participants

Reaction Steps

3-Chloro-6-(4-chloro-2-fluoro-3-methoxyphenyl)-3-chloro-4-oxo-1,4,5,6-tetrahydropyridine-2-carboxylic acid methyl ester (33; 1.612 g, 4.63 mmol) was suspended in MeOH (20 mL). Hydroxylamine hydrochloride (966 mg, 13.9 mmol) was added followed by pyridine (3 mL). The reaction mixture was stirred for 18 h at room temperature and then for 4 h at 40° C. The solvent was removed by rotary evaporation. H2O (100 mL) was added, and the resulting solid was filtered, washed with H2O followed by MeOH to give 3-chloro-6-(4-chloro-2-fluoro-3-methoxyphenyl)-4-hydroxyimino-1,4,5,6-tetrahydropyridine-2-carboxylic acid methyl ester (34; 1.353 g, 81%) as a white powder: mp 174-176° C.; 1H NMR (300 MHz, DMSO-d6) δ 11.23 (s, 1H, NOH), 7.35 (dd, JF-H=1.5 Hz, JH-H=8.7 Hz, 1H, aromatic), 7.17 (dd, JF-H=JH-H=8.7 Hz, 1H, aromatic), 6.93 (br s, 1H, NH), 4.69 (m, 1H, H6), 3.88 (s, 3H), 3.79 (s, 3H), 3.03 (dd, J=4.5, 16 Hz, 1H, H5a), 2.74 (dd, J=9.0, 16 Hz, 1H, H5b); Anal. Calcd for C14H13Cl2FN2O4: C, 46.30; H, 3.61; N, 7.71. Found: C, 46.77; H, 3.64; N, 7.42.

Provenance & Evidence