反应详情

温度

50 °C

6.85 g (20.271 mmol) of the compound from Example 81A were dissolved in 300 ml of ethanol, 7.629 g (40.542 mmol) of dimethyl 2,2-dimethyl-3-oxobutanedioate (described in J. Am. Chem. Soc. 124(14), 3680-3691; 2002) were added and the mixture was stirred at 50° C. overnight. After cooling, a precipitate was filtered off and washed with ethanol. The filtrate was concentrated and then purified by preparative HPLC (methanol:water-75:25). This gave 3.30 g (33% of theory) of the title compound.

1. temperatureAfter cooling
2. filtrationa precipitate was filtered off
3. washwashed with ethanol
4. concentrationThe filtrate was concentrated
5. custompurified by preparative HPLC (methanol:water-75:25)