反应详情

To 5-benzyloxyamino-piperidine-2-carboxylic acid benzyl ester (0.857 g, 2.51 mmol) having diastereo ratio of (2S,5R)/(2S,5S)=77.4/22.6 (54.8% de), isopropanol (4.86 g) and oxalic acid (0.227 g, 2.52 mmol) were added, and the obtained mixture was stirred for 2 hours. The precipitate was filtrated, and washed with isopropanol (0.83 g) for 2 times, and dried at 50° C. under reduced pressure to obtain 5-benzyloxyamino-piperidine-2-carboxylic acid benzyl ester oxalate (0.937 g, 2.18 mmol, yield: 87%). The diastereo ratio of this solid was (2S,5R)/(2S,5S)=88.4/11.6 (76.7% de).

1. additionwere added
2. filtrationThe precipitate was filtrated
3. washwashed with isopropanol (0.83 g) for 2 times
4. customdried at 50° C. under reduced pressure