Acetic Acid → (3S)-2-[(2R)-3-cyclopentyl-2-({formyl[(phenylmethyl)oxy]amino}methyl)propanoyl]-1-{[(phenylmethyl)oxy]carbonyl}-3-pyrazolidinecarboxylic acid

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Reaction Steps

(2R)-3-Cyclopentyl-2-({formyl[(phenylmethyl)oxy]amino}methyl)propanoyl fluoride (4 g, 13.01 mmol) was added into the solution of (3S)-1-{[(phenylmethyl)oxy]carbonyl}-3-pyrazolidine carboxylic acid (3.58 g, 14.32 mmol) in dichloromethane (DCM) (52.9 ml), and followed by adding Hunig's base (6.80 ml, 39.0 mmol). The reaction mixture was stirred for 2.5 hrs at ambient temperature. The reaction was diluted with DCM (200 ml), and then acetic acid (9 ml) was added. The resulting solution was washed with aqueous NH4Cl (200 ml). The aqueous solution was extracted with DCM (2×50 ml). The combined organic layers were dried over anhydrous Na2SO4, filtered and concentrated to give a residue. The desired product was precipitated while ethyl acetate (a few ml) was added. The desired product was filtered and washed with ethyl acetate. 3.49 g of desired product as a white solid was collected. The filtrate was purified by silica Gel chromatography (0-100% Ethyl acetate in Hexane). The solvent was removed under reduced pressure to give a solid. The solid was added about 10 ml of MeCN. The desired product (870 mg) as a white solid was collected via filtration. All desired products were combined to yield the final batch of (3S)-2-[(2R)-3-cyclopentyl-2-({formyl[(phenylmethyl)oxy]amino}methyl)propanoyl]-1-{[(phenylmethyl)oxy]carbonyl}-3-pyrazolidinecarboxylic acid (4.36 g, 8.11 mmol, 62% yield). MS (ES+) m/z 538.1 (MH+).

Provenance & Evidence