反应详情

A solution of N-(2-acetyl-4-chlorophenyl)trifluoromethanesulfonamide 19 (300 mg, 0.99 mmol), O-(2,5-bistrifluoromethylbenzyl)hydroxylamine hydrochloride (296 mg, 1.0 mmol) and anhydrous NaOAc (53 mg, 0.65 mmol) in MeOH (5 mL) and H2O (15 mL) was adjusted to pH 4.5 with AcOH and heated for 15 h at reflux. The reaction mixture was concentrated under vacuum and the residue filtered through a pad of silica (eluting with CH2Cl2). Purification by radial thin layer chromatography (eluting with CH2Cl2/PE, 1:19 to 1:9) afforded N-{2-[1-(2,5-bistrifluoromethylbenzyloxyimino)ethyl]-4-chlorophenyl}trifluoromethanesulfonamide 120 (100 mg, 19%), as a pale yellow solid. M.p. 73-75° C. 1H n.m.r. (200 MHz, CDCl3) δ 10.94, br s, 1H; 7.88-7.71, m, 3H, 7.60, d, J=8.8 Hz, 1H, 7.50, d, J=2.4 Hz, 1H, 7.33, dd, J=2.4 and 8.8 Hz, 1H, 5.46, s, 2H, 2.41, s, 3H.

1. temperatureheated for 15 h
2. temperatureat reflux
3. concentrationThe reaction mixture was concentrated under vacuum
4. filtrationthe residue filtered through a pad of silica (eluting with CH2Cl2)
5. customPurification
6. washby radial thin layer chromatography (eluting with CH2Cl2/PE, 1:19 to 1:9)