Sodium Bicarbonate → (2S*,3R*)-3-hydroxy-2-[(4-phenylphenyl)-methoxy-carbonylamino]-pentanoic acid

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Reaction Steps

To a stirred mixture of (2S*,3R*)-2-amino-3-hydroxy-pentanoic acid (0.068 g, 0.51 mmol) and NaHCO3 (0.128 g, 1.53 mmol) in H2O (2.0 mL), at rt, the isomeric mixture containing (4-phenylphenyl)-methyl-2-pyridyl carbonate and (4-phenylphenyl)-methyl-2-oxopyridine-1-carboxylate (0.233 g, 0.77 mmol) [prepared as for example 17, step 1] in THF (2.0 mL) was added. After 15 h at rt, the crude mixture was rotary evaporated to remove the organics and subsequently extracted with Et2O (3×10 mL). The aqueous phase was acidified with 2.0 M HCl solution to pH 2-3 and subsequently extracted with AcOEt (3×20 mL). The organic fraction was dried over Na2SO4, filtered and concentrated to dryness to afford the title compound (0.164 g, 93% over 3 steps), as an off-white solid, which was used in the next step without further purification. MS (ESI) m/z: 361 [M−NH4]+; (ESI) m/z: 342 [M−H]−. 1H NMR (DMSO-d6) δ 0.85 (t, J=7.38 Hz, 3H), 1.42 (p, J=7.31 Hz, 2H), 3.81 (td, J=3.02, 6.87 Hz, 1H), 4.07 (dd, J=3.04, 9.23 Hz, 1H), 4.66 (s, 1H), 5.10 (s, 2H), 6.92 (d, J=9.21 Hz, 1H), 7.28-7.56 (m, 5H), 7.59-7.78 (m, 4H), 12.59 (s, 1H).

Provenance & Evidence