반응 #66652

반응 방정식

NH4Cl

cyclohexyl-(3-methoxy-benzylidene)-amine

THF

Iodoethane

HCl

THF

2,2,6,6-tetramethylpiperidine

n-butyllithium

THF

→

2-ethyl-3-methoxy benzaldehyde

수율 63.0%

용매

H2O

반응 조건

후처리

1. 1
   온도drop-wise maintaining the internal temperature below −10° C
2. 2
   온도After 1 h the solution was cooled to −78° C
3. 3
   온도to warm to rt over 45 min
4. 4
   추출extracted with Et2O
5. 5
   세척The combined organics were washed with H2O
6. 6
   세척washed with brine
7. 7
   건조dried over MgSO4
8. 8
   여과filtered
9. 9
   농축concentrated in vacuo
10. 10
    기타to give a crude imine as an oil
11. 11
    온도After 2 the solution was cooled
12. 12
    추출the mixture was extracted with ethyl acetate
13. 13
    세척The combined organics were washed with H2O
14. 14
    세척washed with brine
15. 15
    건조dried over Na2SO4
16. 16
    여과filtered
17. 17
    농축concentrated in vacuo
18. 18
    기타to give a crude oil
19. 19
    기타Purification via flash chromatography (98:2 hexane/ethyl acetate)

실험 절차

To a solution of 2,2,6,6-tetramethylpiperidine (4.67 g, 33 mmol) in 75 ml THF at −15° C. was added n-butyllithium (12.6 ml, 32 mmol, 2.5 in hexanes) drop-wise maintaining the internal temperature below −10° C. After 15 min a solution of cyclohexyl-(3-methoxy-benzylidene)-amine (3.259 g, 15.0 mmol) in 5.0 ml THF was added and the solution was allowed to stir at −15° C. After 1 h the solution was cooled to −78° C. Iodoethane (11.9 ml, 150 mmol) was added in one portion and the solution was allowed to warm to rt over 45 min, poured into 10% NH4Cl, and extracted with Et2O. The combined organics were washed with H2O, washed with brine, dried over MgSO4, filtered and concentrated in vacuo to give a crude imine as an oil. The oil was taken up in 90 ml of THF and HCl (22 ml, 89 mmol, 4.0 M) and warmed to reflux. After 2 the solution was cooled. H2O was added and the mixture was extracted with ethyl acetate. The combined organics were washed with H2O, washed with brine, dried over Na2SO4, filtered and concentrated in vacuo to give a crude oil. Purification via flash chromatography (98:2 hexane/ethyl acetate) gave 2-ethyl-3-methoxy benzaldehyde (1.543 g, 63%, 2 steps) as a clear oil.

출처