[CH3:1][O:2][C:3]1[C:8]([O:9][CH3:10])=[CH:7][CH:6]=[CH:5][N:4]=1.[Li]CCCC.CN([CH:19]=[O:20])C.[Cl-].[NH4+]>C1COCC1>[CH3:1][O:2][C:3]1[C:8]([O:9][CH3:10])=[C:7]([CH:19]=[O:20])[CH:6]=[CH:5][N:4]=1To a solution of 2,3-dimethoxypyridine (1.0 g, 7.19 mmol) in dry THF (30 mL), cooled to −78° C., was added 2.5 M nBuLi in hexanes (6.33 mL, 15.8 mmol). The mixture was allowed to warm to 0° C. and stirred for 1 hour, before cooling to −78° C. A solution of DMF (2.4 mL, 31.5 mmol) in THF (5 mL) was added. The reaction mixture was allowed to warm to 0° C. and saturated aqueous ammonium chloride solution was added. The resultant biphasic mixture separated and extracted twice with diethyl ether. The combined organic phase was washed with water, and brine, dried (Na2SO4), filtered, and concentrated in vacuo. The resultant residue was subjected to flash chromatography (SiO2, gradient 15 to 20% ethyl acetate in cyclohexane) to afford the title compound (0.79 g, 65%) as a white solid. LCMS (Method B): RT-=2.71 min, [M+H]+=168.
Wird geladen…