反应详情

10.0 g (47.8 mmol) of the compound from Example 5A and 8.3 g (57.3 mmol) of the compound from Example 11A are initially charged in 100 ml of ethanol, and 1.5 ml (2.2 g, 19.0 mmol) of trifluoroacetic acid are added. The mixture is stirred under reflux for 12 h. The precipitated crystals are filtered off, the filter residue is washed with ethanol and the intermediate is dried under reduced pressure overnight. The intermediate is then suspended in 20 ml of methanol, 100 ml of a 4 M solution of hydrogen chloride in dioxane are added and the mixture is stirred at RT for 1 h. The solid is filtered off, the filter residue is washed with dioxane, ethyl acetate and diisopropyl ether and the product is dried under reduced pressure. Yield: 4.6 g (32% of theory)

1. temperatureunder reflux for 12 h
2. filtrationThe precipitated crystals are filtered off
3. washthe filter residue is washed with ethanol
4. customthe intermediate is dried under reduced pressure overnight
5. addition100 ml of a 4 M solution of hydrogen chloride in dioxane are added
6. stirringthe mixture is stirred at RT for 1 h
7. filtrationThe solid is filtered off
8. washthe filter residue is washed with dioxane, ethyl acetate and diisopropyl ether
9. customthe product is dried under reduced pressure