反应详情

温度

-60 °C

1.075 Ml. of 1.6 molar n-butyllithium in hexane is added to a solution of 0.242 ml. of diisopropylamine in 15 ml. of dry tetrahydrofuran. 0.300 Ml. of hexamethylphosphoric triamide is added and the mixture is cooled to about -60° C. 0.465 G. of methyl (5-oxo-5H-dibenzo[a,d]-cyclohepten-2-yl)acetate is added, and after 15 minutes, 0.137 ml. of ethyl iodide is added. The mixture is warmed slowly to room temperature and a further 0.05 ml. of ethyl iodide is added. After 30 minutes an additional 0.05 ml. of ethyl iodide is added. After 30 minutes, a few drops of methanol are added, and then ether and water are added. The organic layer is washed with water, dilute hydrochloric acid and saturated sodium chloride solution, then dried and evaporated to yield the impure product, which, after chromatography on 40 g. silica gel, eluting with hexane:ether (5:1) affords methyl 2-(5-oxo-5H-dibenzo[a,d]cyclohepten-2-yl)butyrate. 0.326 G. of methyl 2-(5-oxo-5H-dibenzo[a,d]cyclohepten-2-yl)butyrate is refluxed for 4 hours in 10 ml. of methanol and 20 ml. of water containing 0.5 g. of sodium hydroxide. The mixture is cooled, washed with ether and acidified with dilute hydrochloric acid. The product is extracted with ether and the extract washed, dried and evaporated to yield 2-(5-oxo-5H-dibenzo[a,d]cyclohepten-2-yl)butyric acid (m.p. 147°-148° C).

1. temperatureThe mixture is warmed slowly to room temperature
2. waitAfter 30 minutes an additional 0.05 ml
3. waitAfter 30 minutes
4. washThe organic layer is washed with water, dilute hydrochloric acid and saturated sodium chloride solution
5. customdried
6. customevaporated
7. customto yield the impure product, which
8. washsilica gel, eluting with hexane:ether (5:1)