Trifluoroacetic acid → 2,5-Difluorobenzohydrazide

To a solution of 2,5-difluorobenzoic acid (3.5 g, 22 mmol) in THF/DMF (20 mL/20 mL) was added EDCI (4.7 g, 24 mmol), DMAP (50 mg) and NH2NHBoc (3.07 g, 23.2 mmol). After stirring for 16 hours, the reaction was quenched with water (30 mL) and diluted with EtOAc (30 mL). The organic layer was then washed with HCl (0.5 M, 20 mL), saturated NaHCO3 (20 mL), and brine (20 mL). The organic layer was then dried over Na2SO4, filtered and concentrated under reduced pressure to afford the crude Boc-protected product, which was then dissolved in DCM (60 mL) at 0° C. TFA (50 mL) was added to the above DCM solution. After stirring for 2 hours, the reaction mixture was concentrated and the residue was dissolved in DCM (60 mL). The solution was washed with saturated NaHCO3 (40 mL) and dried over Na2SO4, filtered and concentrated under reduced pressure to afford the desired crude product.

1. customthe reaction was quenched with water (30 mL)
2. additiondiluted with EtOAc (30 mL)
3. washThe organic layer was then washed with HCl (0.5 M, 20 mL), saturated NaHCO3 (20 mL), and brine (20 mL)
4. dry with materialThe organic layer was then dried over Na2SO4
5. filtrationfiltered
6. concentrationconcentrated under reduced pressure
7. customto afford the crude Boc-protected product, which
8. stirringAfter stirring for 2 hours
9. concentrationthe reaction mixture was concentrated
10. dissolutionthe residue was dissolved in DCM (60 mL)
11. washThe solution was washed with saturated NaHCO3 (40 mL)
12. dry with materialdried over Na2SO4
13. filtrationfiltered
14. concentrationconcentrated under reduced pressure

ORD record

ord-3ea00d9ab25c40729b6f5aff1710bee2

Source dataset

uspto-grants-2012_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08236825B2