Thionyl Chloride → 1-Benzyl-3,3-difluoropyrrolidine-2,5-dione

Temperature

55 °C

To a solution of the crude 4-(benzylamino)-3,3-difluoro-4-oxobutanoic acid in iPrOAc (40 mL), SOCl2 (2.04 mL, 27.9 mmol, 2 eq) was added at ambient temperature. The reaction solution was stirred at 55° C. for 4 hr. The reaction was cooled to 0-5° C. Half saturated brine (50 mL) was added slowly to quench the excess SOCl2. The organic phase was washed with brine (70 mL) and 2 M Na2CO3 (about 50 mL) to pH=8-9, extracted two times with EtOAc. The combined organic layer was washed with brine (50 mL), the organic phase was dried over MgSO4, filtered and concentrated. The crude residue was diluted with CH2Cl2 and filtered to remove precipitate. The concentrated filtrate was purified by column chromatography and eluted with 2-20% EtOAc/Heptane to obtain the title compound as a clear oil (1.74 g, 65%)1H NMR (400 MHz, CDCl3) δ ppm 7.30-7.43 (m, 5 H) 4.76 (s, 2 H) 3.18 (t, J=12.53 Hz, 2 H).

1. temperatureThe reaction was cooled to 0-5° C
2. customto quench the excess SOCl2
3. washThe organic phase was washed with brine (70 mL) and 2 M Na2CO3 (about 50 mL) to pH=8-9
4. extractionextracted two times with EtOAc
5. washThe combined organic layer was washed with brine (50 mL)
6. dry with materialthe organic phase was dried over MgSO4
7. filtrationfiltered
8. concentrationconcentrated
9. additionThe crude residue was diluted with CH2Cl2
10. filtrationfiltered
11. customto remove precipitate
12. customThe concentrated filtrate was purified by column chromatography
13. washeluted with 2-20% EtOAc/Heptane

ORD record

ord-42ea6156bde14fcd85cf520662ed1bf5

Source dataset

uspto-grants-2016_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09290496B2