反应详情

To a solution of methylpyridazine-4-carboxylate (1.00 g, 6.95 mmol) and dimethyl methylphosphonate (889 mg, 6.95 mmol) in THF (20 ml) was added a 2 M solution of lithium diisopropylamide (2 M in THF/heptane/ethylbenzene; 7.3 ml, 14.6 mmol) between −5° C. and 0° C. Then after 5 min the reaction mixture was carefully quenched with 4 M aq. hydrochloric acid solution to adjust the pH to ca. 6 and diluted with dichloromethane. The aqueous layer was separated and extracted 2 times with dichloromethane. The combined organic layers were washed with brine, dried over magnesium sulfate, filtered, and evaporated. Chromatography (SiO2; gradient ethyl acetate to ethyl acetate/methanol 9:1) afforded the title compound (460 mg, 29%). Dark red oil; MS: 231.1 [M+H]+.

1. customThen after 5 min the reaction mixture was carefully quenched with 4 M aq. hydrochloric acid solution
2. additiondiluted with dichloromethane
3. customThe aqueous layer was separated
4. extractionextracted 2 times with dichloromethane
5. washThe combined organic layers were washed with brine
6. dry with materialdried over magnesium sulfate
7. filtrationfiltered
8. customevaporated