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To a stirred mixture of glycine (30 g, 0.3996 mole) in 1N aqueous NaOH (39.96 g, 0.999 mole) was added tert-butanol (270 mL). The mixture was cooled to 0° C. and di-tert-butyl dicarbonate (96.42 g, 0.4395 mole) was added dropwise. The mixture was stirred at ambient temperature for 5 hours. The reaction mixture was then concentrated under reduced pressure and the resulting residue was acidified with citric acid. The product was extracted with ethyl acetate. the organic layer was washed with brine solution, dried over sodium sulfate and concentrated under reduced pressure to afford 49 g (70%) of tert-butoxycarbonylamino-acetic acid. 1H NMR (DMSO-d6): δ 12.8-12.0 (bs, 1H), 7.1 (t, 1H), 3.6 (d, 2H), 1.4 (s 9H). To a stirred solution of tert-butoxycarbonylamino-acetic acid (0.2 g, 0.00114 mol) in DMF (5 mL) was added DIPEA (0.59 g, 0.00457 mol), HOBt (0.193 g, 0.001427 mol) and EDCI.HCl (0.274 g, 0.00143 mol) at ambient temperature. After 5 minutes (2-chloro-phenyl)-piperidin-4-yl-amine dihydrochloride (0.283 g, 0.00114 mol) was added and the resulting mixture was stirred overnight. The reaction mixture was then diluted with cold water. The resulting precipitate was isolated by filtration and purified by column chromatography using basic aluminium oxide (60% ethyl acetate in hexane) to afford 0.41 g (98%) of {2-[4-(2-chloro-phenylamino)-piperidin-1-yl]-2-oxo-ethyl}-carbamic acid tert-butyl ester. LCMS: 368.18 (M+1)+, 93.53%. A solution of {2-[4-(2-chloro-phenylamino)-piperidin-1-yl]-2-oxo-ethyl}-carbamic acid tert-butyl ester (0.41 g, 0.00111 mole) in methanol (10 mL) was added dioxane.HCl (5 mL) and the resulting mixture was stirred at ambient temperature for 10 minutes. The mixture was then concentrated under reduced and the resulting residue was washed with ether to afford 0.34 g (98%) of 2-amino-1-[4-(2-chloro-phenylamino)-piperidin-1-yl]-ethanone hydrochloride. LCMS: 268.11 (M+1)+, 84.63%.

1. concentrationThe mixture was then concentrated
2. washthe resulting residue was washed with ether