General procedure for the synthesis of 1-amino-4-piperidinol from 1-nitrosopiperidin-4-ol: 14 g of 1-amino-4-piperidinol was prepared; lithium aluminum hydride (LAH, 1.0 M, 175 mL) was added batchwise to a tetrahydrofuran (THF, 250 mL) solution of 1-nitrosopiperidin-4-ol (12.9 g) over 40 min. After the addition was completed, the reaction mixture was refluxed for 3 h and subsequently cooled to room temperature and further cooled to 0 °C in an ice bath. The reaction mixture was gradually warmed to room temperature by slowly adding water (40 mL), held for 10 min, and then refluxed for 30 min. The precipitate was collected by filtration, suspended in hot THF (100 mL) and filtered again. All the filtrates were combined, dried with anhydrous sodium sulfate, filtered and concentrated to give the target product 1-amino-4-piperidinol in the form of a light yellow oil. Yield: 10.7 g, 94% yield.
