反应详情

A solution of 4-hydroxy-piperidine-1-carboxylic acid tert-butyl ester (2.2 g; 11.0 mmol), 5-fluoro-2-nitrobenzotrifluoride (2.5 g; 11.9 mmol) and potassium carbonate (3.0 g; 22.0 mmol) in dimethylsulfoxide (25 mL) is heated over night at 100° C. The mixture is then diluted with dichloromethane (200 mL) and is washed with water (25 mL), aq. sat. ammonium chloride (25 mL) and twice with water (25 mL). The organic layer is then filtered and the filtrate is evaporated under reduced pressure. The product is dissolved in a 1 to 1 mixture of dichloromethane and trifluoroacetic acid (16 mL) and the resulting solution is stirred at room temperature until complete conversion is observed (about 30 minutes). After concentration under reduced pressure, the residue obtained is co-evaporated with dichloromethane (3×30 mL). The crude product is diluted in diethylether (25 mL) and a molar solution of hydrochloric acid in diethylether (15 mL) is added under stirring. The solid obtained is finally filtered and is dried under high vacuum to yield the desired product as hydrochloride (1.86 g; 5.7 mmol).

1. washis washed with water (25 mL), aq. sat. ammonium chloride (25 mL) and twice with water (25 mL)
2. filtrationThe organic layer is then filtered
3. customthe filtrate is evaporated under reduced pressure
4. dissolutionThe product is dissolved in a 1 to 1 mixture of dichloromethane and trifluoroacetic acid (16 mL)
5. custom(about 30 minutes)
6. concentrationAfter concentration under reduced pressure
7. customthe residue obtained
8. stirringunder stirring
9. customThe solid obtained
10. filtrationis finally filtered
11. customis dried under high vacuum