反应详情

A 2 L round bottom flask was set up with a mechanical stirrer, thermometer, N2 inlet and reflux condensor. A solution of 3,5-dimethyl-benzaldehyde (70 g. 522 mmol) in 300 mL of methanol was added, followed by the addition of sodium acetate (44 g, 536 mmol). Hydroxylamine-HCl (37 g, 532 mmol) was added portion-wise over 5 minutes, during which time the maximum temperature reached without cooling was 27° C. The mixture was stirred for an additional 2 hours at room temperature. TLC (10% ethyl acetate in hexane) indicated the absence of the starting aldehyde and the appearance of oxime. Most of the methanol was removed on a rotary evaporator, resulting in the formation of a precipitate. Ether and water were added to the concentrated suspension, and then the ether layer was collected, dried over MgSO4, and removed on a rotary evaporator. The white crystalline material was air-dried, resulting in 77 g (100%) of 3,5-dimethyl-benzaldehyde oxime. 1H-NMR (300 MHz, CDCl3)δ(ppm): 8.09 (s, 1H), 7.22 (s, 2H), 7.05 (s, 1H), 2.33 (s, 6H).

1. customA 2 L round bottom flask was set up with a mechanical stirrer
2. temperaturethermometer, N2 inlet and reflux condensor
3. temperaturewithout cooling
4. customwas 27° C
5. customMost of the methanol was removed on a rotary evaporator
6. customresulting in the formation of a precipitate
7. customthe ether layer was collected
8. dry with materialdried over MgSO4
9. customremoved on a rotary evaporator
10. customThe white crystalline material was air-dried
11. customresulting in 77 g (100%) of 3,5-dimethyl-benzaldehyde oxime