反应详情

温度

40 °C

L-tartaric acid (9.51 g) was mixed with methanol (14.18 g) and heated to 40° C. To the resulting solution was added dropwise a 50% toluene solution (28.93 g) of N-[(S)-α-methylbenzyl]-(RS)-proline methyl ester obtained in Example 1 at that temperature. After stirred at the temperature for 1 hour, the reaction mixture was cooled to 0° C. over 14 hours and stirred at that temperature for 2 hours. The crystallized solid was separated by filtration and washed with cold methanol to yield a salt of N-[(S)-α-methylbenzyl]-(S)-proline methyl ester and L-tartaric acid (11.50 g) in 98.8% diastereomeric excess (hereinafter referred to as “d.e.”) and a yield of 40.0%.

1. temperaturethe reaction mixture was cooled to 0° C. over 14 hours
2. stirringstirred at that temperature for 2 hours
3. customThe crystallized solid was separated by filtration
4. washwashed with cold methanol