Pyridine → Methyl (S)-4,4-difluoro-2-isocyanatopentanoate

Temperature

0 °C

The compound from example 6 (6.76 g, 28.8 mmol) was initially charged and dissolved in 240 ml of dichloromethane and 9.46 ml (117 mmol, 4.05 eq) of pyridine, cooled down to 0° C. in an ice bath for 15 min and admixed with 19.86 ml of a 20% phosgene solution in toluene (37.54 mmol, 1.3 eq) within 20-30 seconds. The mixture was stirred at 0° C. for a further 2 h, then the reaction mixture was extracted with cold half-molar HCl and ice. The water phases were reextracted with dichloromethane, and the combined organic phases were washed with ice and saturated NaCl solution, then dried over MgSO4 and filtered off from the desiccant. Concentration by evaporation under reduced pressure left 5.21 g of brown oil (corresponded to a yield of 94%), which was reacted further directly.

1. extractionthe reaction mixture was extracted with cold half-molar HCl and ice
2. washthe combined organic phases were washed with ice and saturated NaCl solution
3. dry with materialdried over MgSO4
4. filtrationfiltered off from the desiccant
5. concentrationConcentration
6. customby evaporation under reduced pressure
7. waitleft 5.21 g of brown oil (
8. customwas reacted further directly

ORD record

ord-67c260589b16453eba0d7d6beba65a87

Source dataset

uspto-grants-2013_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08609681B2