反应详情

Hydroxylamine hydrochloride (5.5 g, 0.079 mol) and sodium acetate (6.5 g, 0.079 mol) were added to a slurry of 2-[3,5-difluoro-4-(methylthio)phenyl]-1-phenylethanone in ethanol (120 mL) and water (30 mL). The mixture was heated and held at reflux for 1 hour, then cooled and allowed to stir for 18 hours at room temperature. Additional water (50 mL) was added, and the mixture concentrated to half its volume. Dilute HCl was added, and the mixture extracted with dichloromethane (1×100 mL), 3×50 mL). The combined extracts were washed with dilute sodium bicarbonate, dried with magnesium sulfate, and concentrated to give a light yellow oil, that was crystallized from ethyl acetate/hexanes to afford 2-[3,5-difluoro-4-(methylthio)phenyl]-1-phenylethanone oxime as white solid (6.2 g, 53%). A second crop (2.3 g, 73% net yield) was also collected. 1H NMR (CDCl3/400 MHz) 7.57-7.60 (m, 2H), 7.35-7.37 (m, 3H), 6.80-6.84 (m, 1.7H), 6.75-6.77 (m, 0.3H), 4.14 (s, 1.7H), 3.83 (s, 0.3H), 2.39 (s, 3H). HRMS m/z 244.0773 (M+H+, calcd 244.0764). Anal. Calcd for C15H13F2NOS: C, 61.42; H, 4.47; N, 4.78; Found: C, 61.44; H, 4.50, N 4.84.

1. temperatureThe mixture was heated
2. temperatureat reflux for 1 hour
3. temperaturecooled
4. concentrationthe mixture concentrated to half its volume
5. additionDilute HCl was added
6. extractionthe mixture extracted with dichloromethane (1×100 mL), 3×50 mL)
7. washThe combined extracts were washed with dilute sodium bicarbonate
8. dry with materialdried with magnesium sulfate
9. concentrationconcentrated
10. customto give a light yellow oil, that
11. customwas crystallized from ethyl acetate/hexanes