反应详情

[(S)-1-(4-Fluoro-benzyl)-2-(4-hydroxy-piperidin-1-yl)-2-oxo-ethyl]-carbamic acid tert-butyl ester (20.2 g, 55 mmol) was dissolved in 4M HCl-dioxane (25 mL) at 25° C. After 3 hours a thick syrup had precipitated, and an additional 4M HCl-dioxanes (10 mL) was added. The mixture was stirred for 2 hours, concentrated and the solid residue suspended in 4M HCl-dioxanes. After 2 hours at 25° C., the mixture was concentrated and the residue coevaporated twice with ether. The resulting solid was stirred in a mixture of ether (75 mL) and hexanes (10 mL) at 25° C. for 18 hours, the mixture filtered, and the filtered solid washed with 1:1 ether-hexanes and dried giving hygroscopic solid (16.3 g, 97%).

1. customAfter 3 hours a thick syrup had precipitated
2. additionan additional 4M HCl-dioxanes (10 mL) was added
3. concentrationconcentrated
4. waitAfter 2 hours at 25° C.
5. concentrationthe mixture was concentrated
6. stirringThe resulting solid was stirred in a mixture of ether (75 mL) and hexanes (10 mL) at 25° C. for 18 hours
7. filtrationthe mixture filtered
8. washthe filtered solid washed with 1:1 ether-hexanes
9. customdried