反应详情

Under a dry nitrogen atmosphere a solution of commercial ethyl 4,6-dimethyl-2-oxo-2H-pyran-5-carboxylate (19.6 g, 0.1 mole) in toluene (20 ml) was added dropwise to a stirred solution of 4-(2-phenylethenyl)morpholine (14.3 g, 0.076 mole) in toluene (200 ml). Preparation of the morpholine derivative is described in U.S. Pat. No. 3,922,237. After the addition, the reaction mixture was heated at reflux for approximately 20 hours. The reaction mixture was then cooled and concentrated under reduced pressure, leaving a residue. The residue was heated at 170° under a dry nitrogen atmosphere for 3.5 hours, allowed to cool to room temperature, and then filtered. The filtrate was purified by column chromatography on silica gel, elution first with n-hexane: ethyl acetate, and finally ethyl acetate, to give ethyl 2,4-dimethyl-[1,1'-biphenyl]-3-carboxylate (3.5 g) as a yellow oil.

1. additionAfter the addition
2. temperaturethe reaction mixture was heated
3. temperatureat reflux for approximately 20 hours
4. temperatureThe reaction mixture was then cooled
5. concentrationconcentrated under reduced pressure
6. customleaving a residue
7. temperatureThe residue was heated at 170° under a dry nitrogen atmosphere for 3.5 hours
8. filtrationfiltered
9. customThe filtrate was purified by column chromatography on silica gel, elution first with n-hexane