Trifluoroacetic acid → 1-(3-(2-Fluoropyridin-3-yl)pyrrolidin-1-yl)ethanone

To tert-butyl 3-(2-fluoropyridin-3-yl)pyrrolidine-1-carboxylate (0.25 g, 0.939 mmol) dissolved in DCM (3.1 mL) was added trifluoroacetic acid (1.05 mL, 14.1 mmol). The reaction mixture was stirred at RT for 1 h. The solvent was evaporated in vacuo and to the residue dissolved in DCM (1 mL) was added acetic anhydride (0.44 mL, 4.7 mmol) and sodium bicarbonate (0.4 g, 4.7 mmol). The reaction mixture was stirred at RT under N2 for 3 h. The reaction mixture was partitioned between 1N NaOH and DCM. The aqueous layer was back extracted with DCM (3×) and the combined DCM layer was dried (Na2SO4) and concentrated. The crude material was purified by chromatography through a Redi-Sep pre-packed silica gel column (40 g), eluting with a gradient of 0% to 100% EtOAc in hexane, then 10% MeOH in EtOAc, to provide 1-(3-(2-fluoropyridin-3-yl)pyrrolidin-1-yl)ethanone as tan oil. [M+H]=209.2.

1. customThe solvent was evaporated in vacuo and to the residue
2. dissolutiondissolved in DCM (1 mL)
3. stirringThe reaction mixture was stirred at RT under N2 for 3 h
4. customThe reaction mixture was partitioned between 1N NaOH and DCM
5. extractionThe aqueous layer was back extracted with DCM (3×)
6. dry with materialthe combined DCM layer was dried (Na2SO4)
7. concentrationconcentrated
8. customThe crude material was purified by chromatography through a Redi-Sep pre-packed silica gel column (40 g)
9. washeluting with a gradient of 0% to 100% EtOAc in hexane

ORD record

ord-d715fcb687544b88a4e7586e6b26e712

Source dataset

uspto-grants-2014_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08759532B2