Reaction Steps
3-O-Benzyl-N-benzyloxycarbonyl-2,6-imino-2,5,6-trideoxy-D-lyxo-hexono-1,4-lactone (26) (321 mg, 0.875 mmol) was dissolved in a 2:1 mixture of acetic acid and water (10 ml) and stirred under hydrogen with palladium black (70 mg) for 48 hours. The reaction mixture was filtered through celite, the solvent removed and the product purified by flash chromatography (CMAW) and ion exchange chromatography. Freeze drying afforded (2S,3R,4R) 3,4-dihydroxypipecolic acid, monohydrate (140 mg, 89%) as a white crystalline solid, m.p. 253°-260° C. with decomposition, [α]20D -1.3° (c, 0.54 in water); νmax (KBr disc) 3390, 1595 (CO), 1400, 1080, 1060 and 890 cm-1 ; 1H NMR (D2O) δ 1.48-1.61 (1H, m, 5-H); 1.99 (1H, ddt, H-5', J5,5' 14.4 Hz, J5', 6;5',6';5',4 3.7 Hz); 2.88 (1H, ddd, 6-H, J6,6' 13.0 Hz, J5,6 11.9 Hz); 3.26 (1H, dt, H-6', J5,6' 3.7 Hz); 3.30 (1H, d, 2-H, J2,3 9.2 Hz); 3.52-3.61 (2H, m, H-3, H-4); 13C NMR (D2O) δ 28.33 (t, C-2); 41.13 (t, C-1); 61.51 (d, H-5); 70.24, 71.85 (2×d, C-3,4); 172.43 (s, C-1). m/z: 124 (M-2×H2O-H+, 100%), 98 (M-H2O-CO2H+, 95%), 116 (M-CO2H+, 75%), 162 (M+H+, 67%). (Found C, 40.16; H, 7.10; N, 7.56. C6H11NO4.H2O requires C, 40.22; H, 7.31; N, 7.82).
