Pyridine → (2S)-1-Acetamido-3-chloropropan-2-yl acetate

Temperatur

42 °C

To a slurry of (S)-1-amino-3-chloro-2-propanol hydrochloride (500 g, 3.43 mol) in methylene chloride (1.54 kg) and acetic anhydride (803 g, 7.87 mol) is added pyridine (340 g, 4.3 mol) over 1 h while maintaining 38 to 46° C. The mixture is then stirred at 21 to 46° C. for 22 h. Water (600 ml) is added at 22 to 24° C. then aqueous potassium carbonate (47 wt %, 2.0 kg, 6.80 mol) while maintaining 6 to 11° C. Water (600 ml) and methylene chloride (600 ml) are added and the phases separated at 24° C. The aqueous is washed with methylene chloride (600 ml) and the combined organics concentrated under reduced pressure to 1.3 liter total volume. Toluene (2×1.0 liter) was added and the mixture concentrated to 1.4 liter after each addition. The mixture is cooled to 24° C. and isooctanes (2.3 liter) added. The resultant slurry is cooled to 0° C. and the precipitate collected by vacuum filtration, washed with isooctanes (700 ml) and dried in a nitrogen stream to give the title compound. This compound can also be prepared according to the procedures disclosed in WO 9924393 or Tetrahedron Letters, Vol. 37, No. 44, pp. 7937-7940.

1. customthe phases separated at 24° C
2. washThe aqueous is washed with methylene chloride (600 ml)
3. concentrationthe combined organics concentrated under reduced pressure to 1.3 liter total volume
4. additionToluene (2×1.0 liter) was added
5. concentrationthe mixture concentrated to 1.4 liter
6. additionafter each addition
7. temperatureThe mixture is cooled to 24° C.
8. additionisooctanes (2.3 liter) added
9. temperatureThe resultant slurry is cooled to 0° C.
10. filtrationthe precipitate collected by vacuum filtration
11. washwashed with isooctanes (700 ml)
12. customdried in a nitrogen stream

ORD-Eintrag

ord-ce27fe380dda453696f70618851eb0ac

Quelldatensatz

uspto-grants-2006_08

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07087784B2