Hydrochloric Acid → (2R)-chloro-3-phenylpropionic acid

温度

37.5 °C

Thionyl chloride (43.8 g, 368.4 mmol) was added dropwise to a solution of 20.4 g (122.8 mmol) of (2S)-2-hydroxy-3-phenylpropionic acid (optical purity 100% ee (S)) in 200 ml of tetrahydrofuran, and the mixture was stirred at 35 to 40° C. for 2 hours. To that solution was added 1.8 g (24.6 mmol) of dimethylformamide, and the mixture was stirred at 42 to 44° C. for 6 hours. This reaction mixture was cooled and, while maintaining the temperature at 20° C., 70 ml of water was added dropwise and, after about an hour of stirring, the mixture was extracted with 200 ml of toluene. Water (70 ml) was added to the organic phase and, after pH adjustment to 9.0 with a 30% aqueous solution of sodium hydroxide, the organic phase was removed by phase separation. To the aqueous phase obtained was added 200 ml of toluene, the pH was adjusted to 1.0 with 35% aqueous hydrochloric acid, and the aqueous phase was removed by phase separation. The toluene was distilled off under reduced pressure from the thus-obtained toluene phase to give 21.1 g (114.3 mmol, yield 93%) of (2R)-2-chloro-3-phenylpropionic acid. The optical purity of the product as determined by the same method as in Example 12 was 99.8% ee (R) (rate of configurational inversion 99.8%).

1. stirringthe mixture was stirred at 42 to 44° C. for 6 hours
2. temperatureThis reaction mixture was cooled
3. temperaturewhile maintaining the temperature at 20° C.
4. stirringof stirring
5. extractionthe mixture was extracted with 200 ml of toluene
6. additionWater (70 ml) was added to the organic phase
7. customafter pH adjustment to 9.0 with a 30% aqueous solution of sodium hydroxide, the organic phase was removed by phase separation
8. customTo the aqueous phase obtained
9. customthe aqueous phase was removed by phase separation
10. distillationThe toluene was distilled off under reduced pressure from the thus-obtained toluene phase

ORDレコード

ord-ace0d3f0bca842909fab2c1f9032469b

出典データセット

uspto-grants-2006_08

DOI

10.6084/m9.figshare.5104873.v1

特許番号

US07094926B2