反应详情

A mixture of 5-chloro-2-methylphenyl-isothiocyanate (9.18 g), N-methyl aminooxy acetic acid hydrochloride (7.78 g), triethylamine (20 g) and chloroform (200 mL) was heated at reflux for one hour, stirred at ambient temperature for one hour, then evaporated to dryness. The residue was dissolved in ethyl acetate (400 mL) and washed with 2N HCl (2×200 mL) then with water (200 mL). The organic phase was dried over anhydrous magnesium sulfate and evaporated to dryness The residue (8 g) was dissolved in benzene (150 mL). Phosphorus pentachloride (7 g) was added in portions. The mixture was heated at reflux for one hour then evaporated to dryness. The residue was dissolved in ethyl acetate (300 mL) and washed with sodium bicarbonate saturated solution (2×200 mL) then with water (200 mL). The organic phase was dried over anhydrous magnesium sulfate and evaporated to dryness. The residue was chromatographed on silica gel (10-20% ethyl acetate in hexane). Crystallization from ethyl acetate/hexane afforded the title compound (2.1 g) as a solid, m.p. 119-121° C. Mass spectrum (El, M.+) m/z 282/284. 1H-NMR (CDCl3; 400 MHz) δ7.32 (d, 1H), 7.23 (d, 1H), 7.13 (s, 1H), 4.81 (ABq, 2H), 4.26 (m, 2H), 2.13 (s, 3H), and 1.40 ppm (t, 3H).

1. temperaturewas heated
2. temperatureat reflux for one hour
3. customevaporated to dryness
4. dissolutionThe residue was dissolved in ethyl acetate (400 mL)
5. washwashed with 2N HCl (2×200 mL)
6. dry with materialThe organic phase was dried over anhydrous magnesium sulfate
7. customevaporated to dryness The residue (8 g)
8. dissolutionwas dissolved in benzene (150 mL)
9. additionPhosphorus pentachloride (7 g) was added in portions
10. temperatureThe mixture was heated
11. temperatureat reflux for one hour
12. customthen evaporated to dryness
13. dissolutionThe residue was dissolved in ethyl acetate (300 mL)
14. washwashed with sodium bicarbonate saturated solution (2×200 mL)
15. dry with materialThe organic phase was dried over anhydrous magnesium sulfate
16. customevaporated to dryness
17. customThe residue was chromatographed on silica gel (10-20% ethyl acetate in hexane)
18. customCrystallization from ethyl acetate/hexane