Water → (2R,3S)-3-hydroxy-2-[methyl-(5-phenylpentoxycarbonyl)-amino]-butanoic acid

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Reaction Steps

To a stirred mixture of [(1R,2S)-1-carboxy-2-hydroxy-propyl]-methyl-ammonium toluene-4-sulfonate (0.1 g, 0.33 mmol) and NaHCO3 (0.05 g, 0.65 mmol) in H2O (1.0 mL), the isomeric mixture containing 5-phenyl-pentyl-2-pyridyl-carbonate and 5-phenyl-pentyl-2-oxopyridine 1-carboxylate (0.14 g, 0.49 mmol) [prepared as for Example 37, step 1] in THF (1.0 mL) was added. After 15 h at rt, the crude mixture was rotary evaporated to remove the organics, diluted and subsequently extracted with Et2O (3×5 mL). The aqueous phase was acidified with 2.0 M HCl solution to pH 2-3 and subsequently extracted with EtOAc (3×10 mL). The organic fraction was dried over Na2SO4, filtered and concentrated to dryness to afford the title compound (0.05 g, 45%), as a mixture of two rotamers (1.5:1 ratio), as a colorless sticky oil. 1H NMR (DMSO-d6) δ 1.07 (d, J=6.3 Hz, 6H), 1.27-1.40 (m, 4H), 1.51-1.66 (m, 8H), 2.53-2.60 (m, 4H), 2.90 (s, 3H, minor rotamer), 2.91 (s, 3H, major rotamer), 3.92-4.02 (m, 4H), 4.16-4.27 (m, 2H), 4.32 (d, J=5.8 Hz, 1H, minor rotamer), 4.47 (d, J=5.4 Hz, 1H, major rotamer), 7.13-7.31 (m, 10H).

Provenance & Evidence