N-benzoyl-4-tert-butoxycarbonylaminomethyl-4-fluoropiperidine (the product of Step 3 of Example 15, 4.42 g, 13.1 mmol) was used as a raw material and reacted with NaOH (2.62 g, 65.5 mmol) at reflux in a mixed solvent of H2O (9.00 mL) and ethanol (90.0 mL) for 15 hours. After completion of the reaction, the mixture was concentrated in vacuum. Water and chloroform were added to the concentrated residue and the organic layer was separated. The organic layer was dried with magnesium sulfate and concentrated under reduced pressure to remove the solvent. The resulting solid was recrystallized by hexane-CH2Cl2 mixed solvent to give 1.77 g (58% yield) of the target product ((4-fluoropiperidin-4-yl)methyl)carbamic acid tert-butyl ester as a colorless solid. Mass spectrum (ESI) m/z: 233 (M + H)+. 1H NMR (CDCl3) δ 4.93 (1H, m), 3.30 (2H, dd, J = 21.5,6.3Hz), 2.91 (4H, m), 1.88-1.34 (4H, m), 1.45 (9H, s). No signal corresponding to the amino group was observed.
![Carbamic acid, [(1-benzoyl-4-fluoro-4-piperidinyl)methyl]-, 1,1-dimethylethyl ester (9CI)](/CAS/20200611/GIF/871022-60-5.gif)
