Trifluoroacetic acid → 2-[[(1,1'-biphenyl)-4-yl]sulfonyl]amino-4-hydroxy-5-(phenylthio)-pentanoic Acid

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Reaction Steps

Methyl 2-[[(1,1′-biphenyl)-4-yl]sulfonyl]amino-4-pentenoate: To a solution of N-Boc-allylglycine methyl ester 1a (4.0 g, 17.6 mmol) in CH2Cl2 (15 mL) is added trifluoroacetic acid (10 mL) slowly, and the resulting mixture is stirred overnight at room temperature. The reaction mixture is concentrated under reduced pressure to dryness then dissolved in dioxane (15 mL) and water (15 mL). To the solution is added triethyl amine (9.8 mL, 70.4 mmol), followed by biphenyl-4-sulfonyl chloride (5.9 g, 21.12 mmol) and the mixture is stirred overnight. The reaction mixture is diluted with water, extracted three times with EtOAc. The combined EtOAc layer is washed with 1 N HCl, H2O, brine, dried, and concentrated to an oil which solidified upon standing. The crude product is recrystallized from EtOAc/hexane to give the desired product.

Provenance & Evidence