(2S,4S)-1-(benzyloxycarbonyl)pyrrolidine-2,4-dicarboxylic acid → L-cis-Pyrrolidine-2,4-dicarboxylic acid

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Reaction Steps

N-CBZ-cis-4-carboxy-L-proline (0.455 g, 1.55 mmol) was dissolved in methanol (37 mL) and transferred into a Parr shaker bottle. After adding 10% Pd-C (0.080 g), the mixture was shaken under an atmosphere of hydrogen at 48-50 psi for 0.5 h on the Parr apparatus. The catalyst was removed by filtration through Celite. The filter-cake was washed with water and the combined filtrate and washings were concentrated in vacuo to yield a white solid, which was recrystallized from H2O-ethanol-acetone to yield 0.206 g (84%) of 4 as colorless prisms: mp 225°-226° C.; [α]25D -40° (c 1.02, H2O); 1H NMR (250 MHz, D2O) δ 4.25 (dd, J=8.6, 7.4 Hz, 1 H, H-2), 3.72 (dd, J=12.0, 6.7 Hz, 1 H, H-5), 3.57 (dd, J=12.0, 8.0 Hz, 1 H, H-5), 3.38 (m, 1H, H-4), 2.71 (app dt, J=13.7, 8.6 Hz, 1 H, H-3), 2.35 (app overlapping dt, J=13.7, 7.4 Hz, 1 H,H-3); 13C NMR (75.5 MHz, D2O) δ 178.75, 176.25, 63.87, 50.16, 45.43, 34.78; IR (KBr) 3600-2200 (broad), 3080, 1690, 1560, 1340, 1230 cm-1 ; MS (CI, 70 eV, methane) m/e 160 (MH+, 14), 114 (100). Anal. Calcd for C6H9NO4 : C, 45.28; H, 5.70; N, 8.80. Found: C, 45.31; H, 5.51; N, 8.75.

Provenance & Evidence