(S)-1-[(S)-1-(2,6-difluoropyridin-3-yl)ethylamino]propan-2-ol (+)-di-p-toluoyl-D-tartrate → (S)-4-[(S)-1-(2,6-difluoropyridin-3-yl)ethyl]-6-methylmorpholine-2,3-dione

Temperature

145 °C

(S)-1-[(S)-1-(2,6-difluoropyridin-3-yl)ethylamino]propan-2-ol (+)-di-p-toluoyl-D-tartrate (199 g) was dissolved in 5 N aqueous sodium hydroxide (450 mL), water (1,000 mL), and 50% toluene-THF (2,000 mL), and the organic layer was separated. The aqueous layer was washed with 50% toluene-THF (800 mL) three times. The organic layers were combined and concentrated under reduced pressure. Then, diethyl oxalate (200 mL) was added to the residue, and the reaction solution was heated and stirred at 140 to 150° C. Three hours later, the reaction solution was diluted with toluene (500 mL) and then ice-cooled while stirring. The precipitated crystals were collected by filtration, washed with toluene and diethyl ether, and then air-dried to obtain 103 g of the title compound.

1. customwater (1,000 mL), and 50% toluene-THF (2,000 mL), and the organic layer was separated
2. washThe aqueous layer was washed with 50% toluene-THF (800 mL) three times
3. concentrationconcentrated under reduced pressure
4. additionThen, diethyl oxalate (200 mL) was added to the residue
5. temperaturethe reaction solution was heated
6. additionThree hours later, the reaction solution was diluted with toluene (500 mL)
7. temperatureice-cooled
8. stirringwhile stirring
9. filtrationThe precipitated crystals were collected by filtration
10. washwashed with toluene and diethyl ether
11. customair-dried

ORD record

ord-fc8ef3e4efd84f7c967ca5c8bac5d7c4

Source dataset

uspto-grants-2009_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07618960B2