反应详情

温度

0 °C

To a solution of 0.9 ml of diisopropylamine in 10 ml of THF, at -78°C., was added 2.3 ml of 2.5 M n-butyl lithium in hexane and the mixture wasstirred for 5 mins. To this solution was added a solution of 1.0 g of the title compound of Step A in 5 ml of THF. The reaction was warmed to 0° C., recooled to -78° C. and then 0.75 ml of methyl chloroformate was added. The reaction mixture was then stirred for 24 h, with gradual warming to room temperature, quenched with 0.5 ml of glacial acetic acid, and poured into a 5% solution of aqueous NaHCO3. The mixture was extracted with chloroform, dried over magnesium sulfate and concentrated. Chromatography on silica gel with 30% ethyl acetate hexane afforded 0.25 g of the title compound, m.p. 177° to 180° C.

1. customrecooled to -78° C.
2. temperaturewith gradual warming to room temperature
3. customquenched with 0.5 ml of glacial acetic acid
4. additionpoured into a 5% solution of aqueous NaHCO3
5. extractionThe mixture was extracted with chloroform
6. dry with materialdried over magnesium sulfate
7. concentrationconcentrated