反应详情

Lithium diisopropylamide (2M in tetrahydrofuran, 6.83 g, 63.7 mmol) was added dropwise to a stirred solution of 3-methylpyridazine (5.0 g, 53.12 mmol) in anhydrous tetrahydrofuran (80 mL) at −78° C. under a nitrogen atmosphere over a period of 20 min. The mixture was allowed to warm to room temperature. The mixture was stirred for 1 h at room temperature and cooled again to −78° C. Diethyl carbonate (12.57 g, 106.2 mmol) in anhydrous tetrahydrofuran (20 mL) was added at −78° C. over a period of 20 min. The reaction mixture was allowed to warm to room temperature, stirred for 16 h and partitioned between ethyl acetate and a saturated aqueous solution of ammonium chloride. The organics were dried over sodium sulfate and concentrated under reduced pressure. The resulting crude material was purified via column chromatography (100-200 mesh silica gel, 50-80% ethyl acetate in petroleum ether) to afford ethyl 2-(pyridazin-3-yl)acetate (600 mg). MS (ES+) (M+H) 167.1569.

1. temperaturecooled again to −78° C
2. temperatureto warm to room temperature
3. stirringstirred for 16 h
4. custompartitioned between ethyl acetate
5. dry with materialThe organics were dried over sodium sulfate
6. concentrationconcentrated under reduced pressure
7. customThe resulting crude material was purified via column chromatography (100-200 mesh silica gel, 50-80% ethyl acetate in petroleum ether)