(2S,4S)-N-Fmoc-4-fluoropyrrolidine-2-carboxamide → (2S,4S)-4-Fluoropyrrolidine-2-carboxamide

(2S,4S)—N-Fmoc-4-fluoropyrrolidine-2-carboxamide (Fa) (354 mg, 1 mmol) was dissolved in 12 ml of a 1:1 mixture of diethylamine and dichloromethane at room temperature. After the mixture was stirred for 1.5 h, all the volatiles are removed. To the obtained residue was added ethyl acetate (10 ml) and water (5 mL), and the mixture was stirred and left. The aqueous layer was separated, washed with 10 ml of ethyl acetate, and evaporated to dryness by a vacuum pump. The residue was dissolved in 2 ml of isopropanol and mixed with ether. The precipitated solid was washed with ethyl acetate and dried in vacuo, giving 118 mg (yield 90%) of (2S,4S)-4-fluoropyrrolidine-2-carboxamide as crystals: 19F-NMR (D2O) δ −172.40 (m, 1 F): 1H-NMR (D2O) δ 2.0-2.5 (m, 2H), 2.95 (dd, 1H, J=38.8, 3.42 Hz), 3.20 (dd, 1H, J=21.6, 1.7 Hz), 3.0 (dd, 1H, J=10.3, 4.1 Hz), 5.16 (dt, 1H, J=53.2, 4.1 Hz): 13C-NMR (D2O) δ 37.52 (d, J=21.7 Hz), 52.68 (d, J=23.1 Hz), 58.49, 94.63 (d, J=171.2 Hz, 4-C), 177.71 (CO).

1. customall the volatiles are removed
2. additionTo the obtained residue was added ethyl acetate (10 ml) and water (5 mL)
3. stirringthe mixture was stirred
4. waitleft
5. customThe aqueous layer was separated
6. washwashed with 10 ml of ethyl acetate
7. customevaporated to dryness by a vacuum pump
8. dissolutionThe residue was dissolved in 2 ml of isopropanol
9. additionmixed with ether
10. washThe precipitated solid was washed with ethyl acetate
11. customdried in vacuo

ORD record

ord-3aa19813645f4aaf880dbcc16c6e765f

Source dataset

uspto-grants-2012_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08203003B2