反应详情

Methanol (4.78 g) and oxalic acid (0.219 g, 2.43 mmol) was added to 5-benzyloxyamino-piperidine-2-carboxylic acid benzyl ester (0.804 g, 2.36 mmol) having diastereo ratio of (2S,5R)/(2S,5S)=77.4/22.6 (54.8% de), and the obtained mixture was stirred for 2 hours. The precipitate was filtrated, washed with methanol (0.80 g) for 2 times, and dried at 50° C. under reduced pressure to obtain 5-benzyloxyamino-piperidine-2-carboxylic acid benzyl ester oxalate (0.556 g, 1.29 mmol, yield: 55%). The diastereo ratio of this solid was (2S,5R)/(2S,5S)=99.1/0.9 (98.2 ode).

1. filtrationThe precipitate was filtrated
2. washwashed with methanol (0.80 g) for 2 times
3. customdried at 50° C. under reduced pressure