Ammonium Chloride → HCID 69914526, compound

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of DAST (0.55 g, 3.4 mmol) in DCM (5 mL) at −78° C., 4-hydroxyproline 12b (P=Boc, m=1, R9=n-butyl) (520 mg, 1.7 mmol) in dry DCM (5 mL) was added slowly. The mixture was stirred at −78° C. for 1 h and then at −10° C. for an additional 1 h. DCM (50 mL) was added, followed by aq. NH4Cl (10%, 30 mL). The organic layer was separated, dried over sodium sulfate and evaporated to dryness. The residue obtained was purified by column chromatography using 5% EtOAc in hexanes to obtain 4-fluoro-4-butylproline methyl ester 12c (P=Boc, m=1, R9=n-butyl) (270 mg, 52%) as a colorless oil: 1H NMR (300 MHz, CDCl3) δ 4.41 (m, 2), 3.83 (m, 1), 3.71 (s, 3), 3.45 (dd, J=12.3, 32.7, 2), 2.48 (m, 1), 1.73 (m, 2), 1.40 (m, 12), 0.89 (m, 3); MS (ESPOS): 326 [M+Na]+.

Provenance & Evidence