Methyl 1-benzyl-4-hydroxypiperidine-4-carboxylate

67-56-1

6094-60-6

60437-30-1

Example 1A Synthesis of methyl 1-benzyl-4-hydroxypiperidine-4-carboxylate: 10.52 g (48.64 mmol) 1-benzyl-4-hydroxypiperidine-4-carbonitrile was dissolved in 60 mL of concentrated hydrochloric acid. The reaction mixture was stirred at 90°C for 1 hour. Upon completion of the reaction, the reaction solution was concentrated using a rotary evaporator and dried under high vacuum. The resulting residue was dissolved in a mixture of 150 mL of methanol and 6 mL of concentrated hydrochloric acid. Sulfuric acid was added to the solution and the mixture was subsequently stirred at 50°C for 1 hour. The reaction mixture was cooled, diluted with ethyl acetate and alkalized with saturated sodium carbonate solution. The organic phase was washed with sodium chloride solution, dried over sodium sulfate and finally concentrated by rotary evaporator. 10.8 g (43.6 mmol, 90% yield) of the target product was obtained. The product was analyzed by LC-MS (Method 4): retention time Rt = 2.08 min. Mass spectrum (ESI positive ion mode): m/z = 250 ([M + H]+). 1H NMR (400 MHz, DMSO-d6) data: δ = 7.35-7.2 (m, 5H), 5.28 (s, 1H), 3.63 (s, 3H), 3.45 (s, 2H), 2.53-2.4 (m, 2H, partially masked by DMSO), 2.38-2.2 (m, 2H, partially masked by DMSO), 2.38-2.2 (m, 2H). 2.38-2.2 (m, 2H), 1.9-1.78 (m, 2H), 1.59 (d, 2H).