反应详情

A 2 L 3-necked round bottom flask, equipped with magnetic stirring and nitrogen inlet, was charged with 153 g (0.71 mol) of (4R,5R)-4,5-dimethyl-3-oxo-octanoic acid ethyl ester and 600 mL of anhydrous EtOH. The solution was cooled to 0° C.–5° C. with an ice bath and 65.6 g (0.79 mol) of methoxylamine hydrochloride was added, followed by 58.6 g (0.71 mol) of sodium acetate. This flask contents were slowly warmed to room temperature (about 2 hours) and the reaction mixture was stirred at room temperature for another 24 hours. The solvent (EtOH) was removed under reduced pressure and the mixture was charged with CH2Cl2 (2×300 mL), which was subsequently removed. The mixture was cooled to RT, diluted with CH2Cl2 (300 mL), stirred at room temperature for 0.5 hours, and filtered under 5 psig of nitrogen. The filter cake was washed with CH2Cl2 (150 mL). The filtrate was concentrated under vacuum (50° C.) to give 172 g (99% yield) of the titled compound as a light yellow oil: 1H NMR (400 MHz, CHLOROFORM-D) 0.87 (t, J=3.5 Hz, 5H), 0.89 (d, J=7.2 Hz, 3H), 1.08 (d, J=7.0 Hz, 3H), 1.24 (t, J=7.2 Hz, 4H), 1.3–1.55 (m, 2H), 2.25 (m, 1H), 3.15 (q, J=19.5 Hz, 2H) 3.81 (s, 3H), 4.14 (q, J=7.0 Hz, 2H).

1. customA 2 L 3-necked round bottom flask, equipped
2. temperatureThe solution was cooled to 0° C.–5° C. with an ice bath
3. stirringthe reaction mixture was stirred at room temperature for another 24 hours
4. customThe solvent (EtOH) was removed under reduced pressure
5. additionthe mixture was charged with CH2Cl2 (2×300 mL), which
6. customwas subsequently removed
7. temperatureThe mixture was cooled to RT
8. additiondiluted with CH2Cl2 (300 mL)
9. stirringstirred at room temperature for 0.5 hours
10. filtrationfiltered under 5 psig of nitrogen
11. washThe filter cake was washed with CH2Cl2 (150 mL)
12. concentrationThe filtrate was concentrated under vacuum (50° C.)