Diethyl Ether → 6,7-Dimethoxy-2-methylquinoxaline

Temperature

0 °C

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 3M 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 hour, 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 CH2Cl2, H2O, and NaCl are then added and the mixture is filtered. The resulting solution is poured into a separately 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).

1. temperatureto warm to room temperature
2. temperaturerefluxed for 1.5 hours
3. temperatureThe mixture is cooled
4. customquenched with 10% HCl
5. stirringstirred 10 minutes
6. additionCH2Cl2 and H2O are added to the reaction
7. stirringthe mixture stirred overnight
8. additionAdditional CH2Cl2, H2O, and NaCl are then added
9. filtrationthe mixture is filtered
10. additionThe resulting solution is poured into a separately funnel
11. washthe aqueous layers are washed 3× with CH2Cl2
12. washwashed with brine
13. dry with materialdried (MgSO4)
14. concentrationconcentrated onto silica gel
15. customchromatographed (50%-80% EtOAc/hexanes)

ORD record

ord-fb5e51853edf4956b360087459fae8bb

Source dataset

uspto-grants-2001_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06180632B2