Acetic Acid → (2S,3R,4R)-3,4-dihydroxypyrrolidine-2-carboxylic acid

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Reaction Steps

(2S, 3R, 4R)-3-benzyl-N-benzyloxycarbonyl-4-hydroxyproline (17) (523 mg, 1.95 mmol) was dissolved in glacial acetic acid (12 ml) containing palladium black (100 mg) and stirred under hydrogen at atmospheric pressure for 48 hours. The solution was filtered and the solvent removed. Purification by flash chromatography (CMAW) and ion exchange resin gave (2S, 3R, 4R)-3,4-dihydroxyproline (220 mg, 93.5%) as a white crystalline solid, m.p. 220°-245° C. decomposed without melting (lit.37 250° dec.), [α]20D -12.2° (c, 0.83 in water) [lit.37 [α]D25 -19° (c, 0.4 in water)]; νmax (KBr disc) 3260, 1615 (CO), 1370, 1270, 1075, 1050 and 760 cm-1 ; 1H NMR δ (D2O) 3.35 (1H, d, H-5, J5,5' 12.5 Hz); 3.44 (1H, dd, H-5', J4,5' 3.7 Hz); 3.90 (1H, s, H-2); 4.14 (1H, dt, H-4, J3,4 1.2 Hz); 4.36 (1H, bs, H-3). 13C NMR (D2O) δ 51.71 (t, C-5); 66.33 (d, C-2); 74.75 (d, C-4); 79.14 (d, C-3); 171.86 (s, C-1). m/z: 124 (100%), 104 (77%), 148 (M+H+, 75%), 84 (67%).

Provenance & Evidence