반응 #51632

반응 방정식

MeMgBr

Et2O

2-Chloro-6,7-dimethoxyquinoxaline

→

title compound

2-Methyl-6,7-dimethoxyquinoxaline

용매

THF

반응 조건

후처리

1. 1
   온도to warm to room temperature
2. 2
   온도then refluxed for 1.5 hours
3. 3
   온도The mixture is cooled
4. 4
   기타quenched with 10% HCl
5. 5
   workup.STIRRINGstirred 10 minutes
6. 6
   workup.ADDITIONCH2Cl2 and H2O are added to the reaction
7. 7
   workup.STIRRINGthe mixture stirred overnight
8. 8
   workup.ADDITIONAdditional CH2Cl, H2O, and NaCl are then added
9. 9
   여과the mixture is filtered
10. 10
    workup.ADDITIONThe resulting solution is poured into a separatory funnel
11. 11
    세척the aqueous layers are washed 3× with CH2Cl2
12. 12
    세척washed with brine
13. 13
    건조dried (MgSO4)
14. 14
    농축concentrated onto silica gel
15. 15
    기타chromatographed (50%-80% EtOAc/hexanes)

실험 절차

The title compound is prepared using an adaptation of the published method of Tamao, et al. Tetrahedron, 1982, 38, 3347-3354. To a THF solution under argon is added 2-Chloro-6,7-dimethoxyquinoxaline (5 g, 26 mmol) and NiCl2 (dppp) (0.14 g, 0.26 mmol). The reaction mixture is cooled to 0° C., and a 3 M solution of MeMgBr in Et2O (13 mL, 39 mmol) is added portionwise. The reaction mixture is allowed to warm to room temperature, stirred for 1 hours then refluxed for 1.5 hours. The mixture is cooled, quenched with 10% HCl, stirred 10 minutes, then made basic with 5% NaOH. CH2Cl2 and H2O are added to the reaction, and the mixture stirred overnight. Additional CH2Cl, H2O, and NaCl are then added and the mixture is filtered. The resulting solution is poured into a separatory funnel, and the aqueous layers are washed 3× with CH2Cl2. The organic layers are combined, washed with brine, dried (MgSO4), concentrated onto silica gel, and chromatographed (50%-80% EtOAc/hexanes) to provide a orange solid (49% yield).

출처